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Home My WebLink About20 Development of Bicycle Facilities1999 american association of state highway and transportation officials 444 north capitol street, nw washington , de 20001 (202) 624-5800 (tel) (202) 624-5806 (fax) www.aashto .org prepared by the aashto task force on geometric design ©Copy ri ght 1999 by the Ameri ca n A ss ociatio n of State Hi ghway and Transpo rtation Officia ls. A ll Rig hts Reserved. Printed in the United States of America . This book, or parts thereof, m ay not be reprodu ced in any form without permission of th e publishe rs. Printed in th e United States of America . ISBN : 1-56 051-10 2-8 AASHTO EXECUTIVE COMMITTEE 1999 President DAN FLOWERS, Arkansas Vice President THOMAS R. WARNE , Utah Secretary-Treasurer CLYD E E. PYERS, Maryland Elected Regional Rep resentatives Region I GLENN GERSHANECK , Ver mont JAMES SULLIVAN, Connecticut Region II ELIZABETH S. MABRY, South Carolina KAM K. MOVASSAGHI , Louisiana Region Ill GORDON PROCTOR, Ohio JAMES C. CODE LL , 111 , Kentucky Region IV DWIGHT BOWER, Id aho SID MORRISON, Washington Executive Director, Ex Offi c io JOHN HORSLEY , Washington, D .C. TASK FORCE ON GEOMETRIC DESIGN Robert L. Walters, Chairman William Prosser, Secretary Region 1 New Hampshire New Jersey New York Port Author ity of NY & NJ FHWA Region 2 Alabama Arkansas Kentucky Mississippi West Virg ini a Region 3 Illinois Kansas Nebraska Ohio Region 4 Arizona California N ew Mexico N evada Texas Wyoming Donald A. L ytord Charles A. Goessel Philip J. Clark Robert P. Parisi William Prosser, Secretary Don T. Arkle Robert L. Walters, Chair John Sacksteder John Pickering Norman H. Roush Ken Lazar Jam es 0. Brewer Ted Watson Larry Sutherland Terry Otterness Jerr y Champa Charlie V. Trujillo Steve R. Oxoby Mark A. Marek Pau I Bercich American Public Works Association N at ion al Assoc iation of County Engineers N at ional League of Cities John N. LaPl ante Dennis A. Grylicki H aro ld E. Bastin HIGHWAY SUBCOMMITTEE ON DESIGN 1999 KENNETH I. W ARREN , Mi ss iss ippi , Ch a irman JAMES F. BYRNES , JR ., CONNE CTICUT , Vi ce Ch a irm an HENRY H. RENTZ , FHWA , Secreta r y ALAB A MA, D o n T. A rkl e, St eve n E. W alker AL ASKA , M i ke Down in g A RIZ ONA, Jo hn L. Lo ui s ARK ANSA S, D ale F. Loe , Philli p L. M cCo nn ell CA LIF O RNIA , A l an G len CO LO RA DO, T i moth y J. H arri s CO N N ECTI CUT, Ca rl F. Bard , Jam es F. By rn es , Jr ., Bradl ey J. Smit h DEL AWA RE , Mi c hae l A. An ge lo , Jose ph M . Sa tterf ield , Jr ., M ic hae l H . Si m mo ns DI STRI CT OF COL UMBIA, Sa nfo rd H . Vini ck FL O RI DA, Bill y H attaway, Ji m M i ll s, Fr eddi e L. Si m mo ns GE O RG IA , James Kenn erly , Josep h Pall adi , W alker W . Sco tt HAWA II , Larr y Leopa rdi IDA H O , Steve n Hutc hin so n ILLIN O IS, Willi am T. Sunl ey INDI ANA, Ph el ps H . Klik a IOWA , Jay L. Ch ig l o, D o nald L. Eas t, D av id L. Littl e KANSAS , Ri c hard G . Ad am s, James 0 . Br ewe r KE NTUC KY , D av id Kr att, Charl es S. Ray m er, Jo hn Sac ksteder LOUI SIA NA, N . Kent Israe l , Ni c k Kali va do , 111 , Ll oyd "Budd y" Po rt a M A INE , Mi c hae l E. Bu rn s MARYL A ND, Robe rt D o ugl ass, Kirk G. M cC l ell and M ASSAC HUSETT S, Jo hn Blun do, Stanl ey W oo d, Jr. MI C HI GA N , Pau l F. Mill er MIN N ESOTA, D elb ert "D el " Gerd es MI SS ISS IPPI , Jo hn Pi c kerin g, W ende l T . Ru ff, Kenn eth I. W arr en MI SSOU RI , Hum be rt Sfr edd o , J.T. Bill Yarn ell , Jr . M ON TA NA, Ro nald E. Willi am s NEBR AS KA , El do n D . Po p pe NEV A DA, Su sa n M artin o vi c h, St eve R. O xo b y NEW H A MPSHIRE , Craig A . Gree n NEW JERSEY , Ri c hard W . Dunn e, Art hur J. Ei sdo rfe r, C harl es Goesse l , Char les Miller NE W M EXIC O , Roy M aes tas NE W YO RK , Peter J. Bell air, Phili p J. Cl ark , Robe rt A. D enni so n N O RTH CAR O LI N A , Len Hill , D o n R. M o rt o n, G.T. (Tom ) Sh ea rin N O RT H DAKO TA , Ken Bir st OH IO , Larry J. Sh annon OKLA H OMA, Christin e M . Senkowski , Bru ce E. Tay lo r OREGON , Jeff Sc hei c k PENNSYLVAN IA , Ma hend ra G. Pat el , D ean A . Sc h rei be r RHODE ISLAND , J. Mich ae l Benn ett SOUT H CAROLINA, Wi ll iam M . Dubose , 11 1, Rocqu e Kn eece , Rob ert I. Pratt SOUT H DAKOTA, Timothy Bjorn eberg, Larr y En gbrecht TENNESSEE , James P. A l ex ander, H arri s Sco tt, Ji m Z ei gler TEXAS , Rob ert Wil son U.S. DOT, H enr y H . Rentz (FHWA), Jo hn Ri ce (FAA ) UTA H , P.K. Moh anty VERMONT, D o nald H . Lat h rop , Rob ert F. Shattuck VIRG IN IA , James T . H arri s, Jimm y Mil ls, Moh amm ed Mi rshahi WAS HI NGTON , Ri c hard A l bin , Bri an J. Zi eg ler WEST V IR G INIA, D avid E. C levenge r, Randolph Epp er ly , Jr ., Norm an H . Rous h WISCONS I N , Jo hn E. H av erb erg, Rob ert F. Pfe iffer WYOM I NG , Paul Berc ic h AFFILIATE MEMBERS A l berta, A l an Kw an Br i ti sh Co l umbi a, M erv Cl ark M ari ana Isl and s, Ed wa rd M . D eleon Gu err ero N ew Bru nsw ic k, C. H erb ert Page N ewfo un d land , Terry M c Carth y Northwest Territo ri es, Peter Vi c ian Ontario , Jos eph A . Bu c ik Sas ka tc hewan, Ted Stobb s ASSOCIATE MEMBERS -ST A TE Po rt A ut hority of NY & NJ , J. Lawrence Wil l i ams ASSOCIATE MEMBERS-FEDERAL U .S . Departm ent of A gri c ulture-For es t Serv i ce, Rich ard Sowa AASH TO St aff Li aison , Ken Kob et sky Table of Contents INTRODUCTION ................................................... 1 Purpose ..................................................... 1 Sco pe ...................................................... 2 Definitions .................................................. 2 Chapter 1 PLANNING ............................................... 5 The Bi cycle ................................................. 5 The Bi cycle U se r ............................................. 5 Choos in g the Appropriate Faci li ty Ty pe ............................ 6 Types of Bicycle Faci liti es ...................................... 7 Inve ntory of Existing Co ndition s .................................. 9 Plans for Improvements ....................................... 10 Se lect io n of a Bicycle Faci lity ................................... 10 Education Programs for Bicyclists a nd Motorists ..................... 13 Chapter 2 DESIGN ................................................. 15 Shared Roadways ................................................... 16 Paved Shou ld e rs ............................................. 16 In c reased La ne Width ......................................... 17 O n-Street Parking ............................................ 17 Pavement Surfa ce Qua li ty ..................................... 18 Dra in age In l et Grates ......................................... 18 Sig ned Shared Roadways ............................................. 19 Des ig nating Sid ewa l ks as Signed Bikeways ........................ 20 Sign in g of Shared Roa dways .................................... 20 Table of Contents Bike Lan es ........................................................ 22 Bike Lane Widths ............................................ 22 Bik e Lanes at Inte rsec t ions ..................................... 25 Bike Lanes and Turnin g Lan es .................................. 25 Bik e Lane Symbol Guidelines ................................... 3 1 S hared Us e Paths ................................................... 33 Separation Betwee n Shared Use Paths and Roadways ................ 33 Width and C lea rance ......................................... 35 D esig n Spee d ............................................... 36 Hori zo nta l A l ig nm ent ......................................... 3 7 Grade ..................................................... 39 Sight Distance .............................................. 40 Path Roadway Intersec t ions .................................... 46 Other Inte rsec t i on D es ig n Issues ................................. 50 Signing and M arkin g ......................................... 53 Pave ment Structure ........................................... 54 Structures .................................................. 55 Drain age ................................................... 56 Li g htin g .................................................... 57 Res tri ction of Motor Vehicle Traff ic ............................... 57 Undesirab ility of Sidewalks as Shared U se Paths ..................... 58 Shared Use with Moto rbikes , H o rs es a nd Snowmobiles ............... 58 O th e r Des ig n Co n sideration s .......................................... 60 Rai l road Cross i ngs ............................................ 60 Bi cyc les o n Fr eeways ......................................... 60 Bi cyc le Fac iliti es throu gh Inte rc hange Areas ........................ 62 Bic ycles at Modern Ro und abouts ................................ 64 Table of Contents Traffic Signals ............................................... 64 Obstruction Mark i ngs ......................................... 67 Bicycle Park in g Faci l iti es ....................................... 67 Add ition a l Bicycl e Amenities ................................... 68 Access i bi li ty Req ui rem ents ..................................... 69 Chap ter 3 OPERATION AND MAINTENANCE ............................ 73 APPE NDIX ........................................................ 75 Rev iew of Le ga l Status ......................................... 75 REFERENCES ...................................................... 77 Table of Contents guide for the development of bicycle facilities 1 Introduction Bicycle trave l has played an historic role in transportation. Even befo re the invention of the automobile, the League of American Wheel men pro- moted improved traveled ways. In creasing ly, transportation offic ial s throughout the United States are recognizing the bicycle as a viab le transportation mode. While recre- ational cycl in g is sti ll the primary use of bicycles in this country, th e number of people using bicycles for com mutin g and other travel pur- poses has bee n increasing sin ce the ear ly 1970s. Nationwide, people are recognizing the energy effi ciency, cost effectiveness, health benefits and environme ntal advantages of bicycl in g. Local, state and federa l agencies are responding to the increased use of bicycles by implementing a wide var iety of bicycle-related projects and programs. The emphas is no w being placed on bicycle transportation re- quires an understanding of bicycles, bicyclists and bicycle facilities. Th is manual addresses these issues and clarifies the elements needed to make bicycling a viable tra nspo rt ation alternative. All highways, except those where cyclists are legally proh i b ited, shou ld be designed and constructed under the assumpt ion that they wi ll be u sed by cyclists . Th erefore, bicycles should be co nsid ered in all phases of transportation planning, new roadway design, roadway reconstruction, and capacity im proveme nt and transit projects. Research co ntinu es to provide additional cr iteri a for the design of app ro- priate bicycle facilities. The selection of a bicycle facility may depend on many factors, in cluding ve hi cular and bicycle traffic cha rac teri stics, ad- jacent land use and expected growth patterns. Chapter 1 provides an ove rvi ew of planning cons id eratio ns for bicycles, a discussion of types of faci lity improvements and a description of facto rs to consider whe n locating a facility. Chapter 2, w hi ch is orga ni zed arou nd the various types of bicycle facilit ies , provides gu id elines to follow w hen co nstructi ng or im prov in g hi ghways and designing and co nstru cting bicy- cle facilities. Chapter 3 provides recommendations for the operation and maintenance of bicycle fac ilities. The Appendix reviews the legal status of bicycles under the Uniform Vehicle Code (UVC 3 ). Purpose Safe , conve ni ent and we ll -designed facilit ies are essent i al to encourage bicycle use. Thi s guide is designed to provide in formatio n on the deve l- opment of facilities to enha nce and encourage safe bicycle travel. The majority of bicycling wi ll take p l ace on ordinary roads w ith no dedicated space for bicycl ists. Bicyclists can be expected to rid e on alm ost all road- Introduction 2 guide for the development of bicycle facilities Introduction ways, as wel l as separated shared use paths and even sidewa l ks , w here permitted to meet specia l co nditi ons. This guid e provides informatio n to hel p acco mmod ate bicycle traffic in most ridin g environments. It is not intended to se t fort h str ict sta nd ard s, but, rather, to present sou nd guide l ines that wi ll be va luable in atta inin g good des ign sens itive to the needs of both b icyclists and other highway users . However , in so me sect io ns of thi s guide, des ign cr iteri a include suggested min imum guid elines. These are recomme nd ed on ly where furth er dev ia- tion from desirab le values cou ld result in unaccepta b le safety co mprom ises. Scope This book provides part of t he in formatio n necessa ry for a safe bicycli ng environment. Facilities are o nl y one of severa l el ements essent ial to a community's overa ll bi cy cle program. Bicycle safety ed ucation and tra inin g, enco urag in g b i cycle use , and the app li catio n and enforce ment of the rules of the road as they pertain to bicyclists and motor ists should be combined with fac ili ties to form a comp rehensive co mmunity ap- proac h to bicycle use. This guid e prov id es in formation o n fac ilities. In formation o n other eleme nts of an overa ll b icycle program ca n be ob- tained from state or local bicycle coordinato rs and other publi catio ns. (See Refere nces at the end of thi s Guide.) The prov ision s for bicycle trave l are consiste nt w ith , and simil ar to, nor- ma l highway engin eer i ng practices . Signs, sig nal s and pavement mark in gs for bicycle fac ili t ies whi ch are prese nted in the Ma nua l o n Uni- form Traffic Control Devices (MUTC0 2 )s hould be used in conju nct ion w ith this guid e. For construction of bicycle faci l ities , state and loca l con- str uct io n spec ifi cat ions sho uld be used. Definitions BICYCLE-Every veh icl e prope ll ed solely by hum an powe r upon wh ic h any person may ride , having two tand em w hee l s, except scoote rs and sim- ilar dev ices. The term "bi cycle" for th is p ub li ca t io n al so includ es t hree- and four-w hee led human -p owered vehicles, but not tricycles for c hildren. BICYCLE FACILITIES-A ge neral term denoting i mproveme nts and pro- v ision s made by public agencies to acco mm odate or enco urage bicycling, including parking and storage faci li ties , and shared roadways not spec if ica ll y designated for bi cycle use. BICYCLE LANE or BIKE LANE-A portion of a roadway wh ich has been designated by str ipin g, signin g and pave ment mark in gs fo r th e preferen- tia l or excl usive use of bicycl ists . BICYCLE PA TH or BIKE PA TH-See Shared Use Path. BICYCLE ROUTE SYSTEM-A system of b i keways des ignated by the jurisdiction having authority with approp ri ate d i rectional and informa- guide for the development of bicycle facilities 3 tion a l route m ark ers , with or w ith out spec if ic bicycle route numbers . Bik e routes should esta blish a co ntinuous routing , but may be a co mbi- nati on of any and a ll types of b i keways. BIKEWA Y-A ge ne ri c term for any road, street, pat h or way w hi c h in some manner i s spec ifi ca ll y designated for bicycle travel, regard less of whether suc h facilities are d es i gnated for th e excl usive us e of bicycles or are to be shared with othe r tra nsportatio n mod es. HIG H WAY-A ge nera l term denoting a publi c way fo r purposes of ve- hi c ul ar trave l , includin g th e e ntire a rea w ithin th e right-of-way . RAIL -TRA IL -A share d use path , e ith er paved o r unpaved , built withi n th e ri ght-of-way of an ex ist in g or former ra ilroad . RI GHT-OF-WAY-A ge neral term denoting land , property o r in terest t herein , usually in a stri p, acqui red for or devoted to transportatio n purposes. RIGHT OF WAY-The ri g ht of one vehicle o r pedestrian to proceed in a l awful ma nn e r in prefe re nce to anothe r ve hicl e or pedestr ian. ROADWAY-The po rtion of the hi ghway, including shoulde rs, inte nd ed fo r vehic ul ar use. RU MBLE STRIP~A tex tured or grooved pavem ent so metim es used o n o r along shoulders of hi ghways to alert motor ists w ho st ray o nto th e should er. SH ARED ROAD WAY-A ro adway wh ic h is open to both b icycle and moto r ve hicle trave l. Thi s may be an ex istin g ro adway, st ree t w ith w id e c urb l anes, or ro ad w ith paved. sho uld ers . SHARED USE PA TH-A bikeway physica ll y sepa rate d from moto rized vehicular traffic by an ope n space o r bar rier and e ith e r within the high- way right-of-way or w ithin a n ind epe nd e nt right-of-way. Shared use paths may al so be use d by ped es tri ans, skate rs , whee lc ha ir users , j ogge rs and othe r non-motorized us ers. SH OULDER-The port io n of the roa dway co nti g uous w it h the trave l ed way for acc ommodat io n of stopped ve hicl es , fo r e me rge ncy use and for late ra l support of sub-base , b ase a nd surface co urses . SIDEWALK-The port ion of a stree t o r hi g hway right-of-way des igned for preferentia l or exclusive use by pedestrians. SIG NED SHARED ROADWAY (S IGNED BIKE ROUTE)-A share d road- way wh ic h has been d es ignated by signin g as a p refe rr ed ro ute for bi cycle use. TR AVELED WAY-Th e po rti on of the road way for the movement of ve- hicl es, ex clusive of shoulders . UNPAVED PA TH-Pat hs not surfaced with asp ha lt or Portland ce m ent concrete. Introduction guide for the development of bicycle facilities 5 Chapter 1 Planning Bicyclists have the same mo bility needs as every oth er user of the tra ns - portation system and use the highway system as their primary means of access to jobs, services and recreational activities . Planning for exist in g and potential bicycle use should be integrated into the overall transpor- tation plan nin g process . All highway improvements provide an opportunity to en hance the safety and conve nien ce of b icycle trave l and most improvements for bicycl e travel also benefit other modes of travel. For example, paved shou ld ers have many safety, operat ion al and maintenance benefits and may also provide a p lace for bicyclists to rid e. Even m in or intersection improve- ments can incorporate the needs of bicyclists through a few simp le measures. The opportun ity to improve cond ition s for bicyclists shou ld be considered during the initial planning and des ign phases of all new high- way projects and highway improvements . Plans for implementing bicycle projects shou ld be consistent with a community's transportation plan and should refl ect ove rall comm unity goals. Some zoning ord inan ces and subdivision regulations inhi bit bicy- cle use and may need to be amended to support shared use paths and bicycle-compatible roadway design, bicycle parkin g and l and use po li - c ies that keep destinations closer to home and work. The Bicycle As Figure 1 shows, bicycl ists require at least 1.0 m (40 in ches ) of esse n- tial operating space based solely on their profi le. An operat i ng space of 1.2 m (4 feet) is assumed as the minimum width for any facility designed for exclusive or preferentia l use by bicyclists . Where motor vehicle traf- f ic volumes , motor ve hicle or bicycl ist speed, and the mix of tru c k and bus traffic inc rease , a more comfortab l e operating space of 1.5 m (5 feet) or more is des i rable. The Bicycle User A lth ough the ir physical d im ens ions may be re lat ively consistent, t he ski ll s, confide nce and preferences of bicyclists vary dramatically. So me riders are co nfid ent rid in g anywhere they are lega ll y allowed to opera te and can negot iate busy and hi gh speed roads that have few , if any , spe- c ial accommodations for bicyclists. Most adult riders are less confide nt and prefer to us e roadways with a more comfo rtabl e amou nt of operat in g space , perhaps with designated space for bicyclists, or shared use paths th at are away from motor vehicle traffic. Children may be confident rid- ers and have excellent b i ke hand ling skills, but have yet to develop the traffic sense and experience of an everyday adu lt rider. A ll categories of 1.00 m 40in Figure 1. Bicycli st Operating Space Planning 6 guide for the development of bicycle facilities Planning rider require smooth riding surfaces with bicycle-compatible highway app urtenances , such as bicycle-safe drainage inl et grates. A 1994 report by t he Federal Hi ghway Adm ini st rat ion 11 used the follow- in g gene ral categories of bicycle user ty pes (A, B and C ) to assis t hi ghway desig ners in determining the impact of differe nt faci l ity types and road- way co nditi o ns o n bicyclists: Adva nced or expe ri enced rid ers are gene rall y using their b i cycles as t hey wo uld a motor ve hicl e. Th ey are riding for co nvenience and speed and want direct access to destinations with a minimu m of detour or de- lay. Th ey are typically co mfortab le riding with motor ve hicl e traffic; howeve r, they need sufficie nt operating space on the trave led way or shou ld er to elimin ate the need for eith er the m se lves or a passi ng motor ve hicl e to shift position . B as ic o r less co nfident ad ult rid ers may al so be using their bicycles for tra nsportat i o n purposes , e.g., to get to the sto re o r to visit frie nd s, but pre- fer to avoid roads with fast an d busy motor vehic le traffic unless there is amp le roadway width to all ow easy overtaking by faster motor ve h icles. Thus , basic r id ers are comfortable rid i ng o n neighborhood streets and sha red use paths and prefer designated fac iliti es such as bike lanes or wide shou ld er lanes on busier st reets . Children, ridin g o n t he ir own or with the ir parents , m ay not travel as fast as their adu lt counterparts but st ill req u ire access to key dest in ations in the ir co mmun ity, suc h as sc hool s, co nvenie nce stores and rec reat ional fac ili t ies. Residential streets w ith low motor vehicle speeds, linked w ith sha red use paths and busier streets with we ll -defin ed pavement markings between bicycles and motor vehicles , c an acco mmodate c hildren w ith - out encourag in g them to ride in the travel l ane of major arte ri als . Choosing the Appropriate Facility Type These three bicycle user types are a he lpful guide to the hi ghway de- sig ner. H oweve r, no one type of bicycle faci lity o r hi ghway des ign suits eve ry bicyclist and no designated bicycle fac ility can overco me a l ack of bicycle operator skill. W ithin any given tra nsportation co rri dor, bicy- clists may be provided with more than o ne option to meet t he travel and access needs of all potentia l use rs. Planners and eng in ee rs sho uld recognize t hat th e c hoice of hi ghway de- sig n w ill affect the level of use , the types of us er t hat can be expected to use any g iven road, and th e leve l of access and m obi lity that i s affo rd ed bicycl ists . For example, a four-lane d ivided hi ghway w ith 3.6-m (12-foot) travel lanes, no sho uld er and an 85 km /hr (55 mph) speed l imit w ill attract on l y the most co nfid ent of riders. Th e sa me road w ith a 1 .5-m (5-foot) shou lder o r bike l ane might provide suff ic ient "co mfortab le op- erat in g space" for man y more adu lt riders, but wo uld still not be co mfortable for ch il dre n or l ess confident ad ults. Th is latter group mi ght o nl y be accommodated through an alterna ti ve route using neighbor- hood st reets lin ked by short sections of shared u se pat h . If suc h an alternative route is prov id ed and the four-lane road has a continuous guide for the development of bicycle facilities 7 paved shou ld er, most experienced and many casual adult riders will continue to use the sho ulder for the sake of speed and convenience . Facilities for bi cyclists should also be planned to provide continuity and co n sistency for all users . Children usin g a path to get to sc hool should not have to cross a major arterial without so me intersect ion controls, and shoul ders and bike lanes should not end abrupt l y and un ann ounced at a difficult intersection or busy stretch of hi ghway . Types of Bicycle Facilities Selection of a bicycle fac ility type is dependent on many factors , incl ud - in g the ab ility of the users , spec ifi c corr idor conditions and facility cost. Th e descriptions below pro vide an overview of eac h faci l ity type and ge neral design. Shared Roadway (No Bikeway Designation). Most bicycle travel in th e United States now occu rs on streets and hi ghways without bikeway de s- ignations. This probably will be tru e in th e future as well. In so me in stances , a commu nity's existing street syste m may be fully adequate for efficient bicycle trave l , and signing and str ipin g for bicycle use may be unnecessary. In other cases, some st reets and highways may be unsuit- ab l e for bicycle trave l at present, and it wou ld be inappropriate to encourage b icycle travel by designating the routes as bikeways. Fina ll y, so me routes ma y not be co nside red hi gh bicycle demand corridors, and it would be in approp ri ate to designate them as bikeways regardless of ro adway conditions (e.g., min or residential streets ). Some rural hi ghways are used by touring bicyclists for interci t y and rec - reat ional travel. In most cases, suc h routes should on ly be designated as bikeways where there is a need for enh anced continuity with other bicy- cle routes. However, the development and maintenance of 1 .2-m (4-foot) pave d shou lde rs with a 100-mm (4 -in c h) edge stripe can sig nifi - ca ntl y improve the safe ty and co nv en ience of bicyclists and motor ists alon g suc h routes . Signed Shared Roadway. Signed shared roadways are designated by bike route signs , and serve either to : a. Provide continuity to other bicycle faci l ities (usual l y Bike Lanes); or b. Designa te preferred routes through high-demand co rr idors. As with bike lanes , sig nin g of shared roadways should indi cate to bicy- cli sts that parti cular advantages exis t to usin g th ese routes compa red w ith alternative routes. This m ea ns that responsible age nc ies have taken act ion s to ass ure that these routes are suitab le as shared routes and wi l l be maintained in a manner co nsistent with the needs of bicyclists. Signing al so serves to adv i se veh icl e dri ve rs that bicycles are present. Bike Lane o r Bicycle Lane. Bike lanes are es tabli shed with approp riate pavement markin gs and signing along st ree t s in corrido rs where t here is significant bicycl e dema nd and where there are distinct needs that can be served by them. The purpose should be to improve co nditi ons fo r bi - Planning 8 guide for the development of bicycle facilities Planning cycl i st s on the streets . Bike lanes are intended to de l ineate the ri ght of way assigned to bicyclists and motorists and to provide for more predict- ab l e movements by each . Bike lanes also help to increase the total capacities of highways ca rr y in g mi xed bicycle and motor ve hicl e traffic. Anot her impo rtant reason for co nstruct i ng bike l anes is to be tter accom- modate bicyclists where insuffi c ient space exists for co mfortab le bicycl in g on existing streets . Thi s ma y be acco m p li shed by reducin g t he width of vehicular l anes or pro hib iting park in g in order to de lineate bike lanes. In additio n to lane st ripin g, other meas ures shou l d be t aken to en- sure that bicycle l anes are effecti ve facilities. In particular, bicycl e-safe dra in age inlet grates sho uld be used , pave m ent surfaces shou ld be smooth, and t raffic signa l s sho ul d be respo nsive to bicycl ists . Re gu lar maintenance of b icycle l anes shou Id be a top priority, since bicyclists are unab le to use a l ane w i th potho les , debr i s o r broken glass. If bicycle travel i s to be improved , specia l effo rt s should be made to as- su re that a high quality network is provided wi th these lanes . H owever, t he needs of both the motorist and the bicycl ist mu st be cons id ered in the dec i sion to provide bike lanes. Shared Use Path. Generally, shared use paths sho ul d be used to serve cor rid ors not se rved by streets and hi ghways or w here wide utility or for- mer railroad right-of-wa y exists , perm itt i ng such faci liti es to be c onstr ucted away from t he influence of paral lel streets . Shared use paths sho u ld offe r op portunities not provid ed by the road system . They can prov id e a recreational oppo rtunity or, in so m e in stances, ca n se rve as di- rect comm ute ro utes if cross flo w by moto r vehicles and pedestrians is minimized. The most co mmon applicatio ns are alon g rivers , ocean fro nts, cana ls, utility rights-of-way, fo rm er or active rai l road r ights-of-way , with in co l lege ca mpuses, or with i n and betwee n parks. There may al so be sit uat ion s where suc h fac il iti es can be prov ided as part of planned developments . Anoth er co mmon app l icatio n of shared use paths is to close gaps in bicycle t rave l ca used by co nst ru ction of cu l-de-sacs , railroads and freeway s or to c ir cumvent natural barriers (rive rs , mo untai ns, etc.). While shared use paths sho ul d be designed with the bicyclist's safety in mind , other use rs such as pedestrians , j oggers, dog wa lkers, people pushi ng baby c arriages , persons in w hee lchairs , skate boarders, in-line skate rs and others are al so likely to use suc h pa th s. In se lect i ng the proper fac i I ity, an overrid in g concern is to ass ure that the proposed faci lity wi ll not encourage or req uire b icyclists or motorists to operate in a manner that is in consistent w ith th e rules of t he road. The needs of both motorists and bicycli sts must be considered in se l ecti ng the app ropriate type of fac i l ity . An important co nsideratio n in se lectin g the type of facility is co ntinu ity . A lternating segme nts of shared use paths and bike lanes al o ng a route are ge nerall y in appropriate and in convenient because street cross in gs by bi- cyc l i sts may be required when the route c hanges cha racter . Also , w ro ng-way bicycle trave l with a hi gher pote nti al for cras hes may occ ur on the street beyond the ends of shared use path s be cause of the incon- venie nce of having to cross the street. guide for the development of bicycle facilities 9 Sidewalks ge nerally are not acceptab le for bicycling . However, in a few limited situat ions , such as on long and narrow brid ges and where bicy- clists are incidental or infrequent users , the sidewalk can serve as an alternate fac ility, provided any sig nifi cant difference in height from the roadway is protec ted by a suitab le barrier between the sidewa l k and ro adway . Inventory of Existing Conditions Pl anning for bicycle faci l ities begins with observ in g and gathering data on the exist in g cond iti ons for bicycle travel. Problems, deficiencies , safety concerns and bicyclists' needs sho uld be identified . The exist in g bicyclin g env ironment sho ul d be observed . Bicycle fac iliti es as we ll as roads not typically used by bicyclists sho uld be exami ned for thei r suit- ability for bicycling . Motor ve hicl e traffic vo l ume, the percenta ge and volume of bus and truck traffic, and the speed of traffic shou ld be co nsid- ered, since they have a significant impact on bicyc l ists. In add ition , obstru ct ions and impedime nts to bicycle trave l shou ld be noted , such as incompatible grates , debr is, shou ld er rumble strips , narrow l anes , drive- ways, rough pavements , c urbside auto parking, bridge expa nsion joints, metal gra te bridge decks , railroad tracks , poor sight dista nce and traffic signals that are not responsive to bicycles. Potential corr id ors for off-road shared use paths should be exp lored , such as former and active railroads' ri ghts-of-way, stream and river corr idors, ca nal towpaths and uti I ity co r- rid ors. Bicycle parking faci l ities sho uld be examined for adequacy in both number and theft p revent ion. Barriers such as rivers , railro ads and freeways should also be id entifi ed and exam in ed for the i r effects on b icy- cle traffic. Bicycle traff ic usua lly is ge nerated w here residential areas are close to accessible destinations . Areas nea r b icycle traffic ge nerato rs shou ld be reviewed, and existing and potential bicycle users identified. Examp les of bicycle t raffic ge nerators include major employment ce nters , schoo l s, parks, shopping cente rs, neighbo rhood s, rec reat ion al fac iliti es, co ll eges and military bases . Co nvenie nt access and bicycle parking shou l d be provided at transit stat ions, ferries and other intermoda l transfer poi nts. Bic ycle co unts can be used to ident ify lo cat io ns of high use. However, caution sho uld be exerc ised when using bicycle counts as a measure of current dema nd . These numbers can cons id erably unde restimate pote n- ti al users. Tr aff ic ge nerator s alon g the prospective route shou ld be eva lu ated as to the potentia l b icycle traffic they wou ld generate, g iven better cond iti ons for bicycling. Bicycle crash studies can als o be usefu l in determining lo cations needing improvement. Publi c partic ipation is esse nti al during the inventory of existing co ndi- t ion s. Observations and surveys of existing bicyclists, as well as the non -bicycl in g public, ca n be ve ry usef ul . Additional so urces of informa- t ion include c iti zen bicycle adviso ry committees, citize n groups , and in d ividuals responsible for recreat io n planning. Planning 1 O guide for the development of bicycle facilities Planning Education programs , exist in g laws affecting bicycling, and enforcement programs shou ld also be exa min ed for their appropriateness and effec- tiveness. Plans for Improvements The in vento ry of existing co nd iti ons provides a foundation of knowledge from which to develop a p lan for system-w id e improvements for bicy- cling. Improvements and programs should address both the physical aspects of the bicycling enviro nm ent as we ll as the educatio n and ac- commodatio n of bicycling in the commun ity. In the most successful exa mples , bicycle-friendly policies have been institutionalized in the systematic, everyday work of agencies at al l leve l s of gove rnment. The physica l improvement plan should address the ph ysica l conditions, ba rriers and inconveniences to bicycling throughout the co mmunity, as we ll as make the best use of ex ist ing bicycle-frie ndl y facilities. The plan sho uld make specific recommendations for a network of on-road and off-road bicycle faci l ities, locations for "s pot improvements" such as dra in age grate replacement, bridge expans io n joints, or intersect ion sig- nal modification , and improvements needed to existing bicycle faci li ties that are substandard or in disrepair . Physica l improvements should be based on the inventory of ex istin g condit ion s and public input. This phys ical improvement p l an should also add ress maintenance needs for both on-road and off-road bikeways , and estab l ish pol icies for coordi- nating maintenance activit ies among different age ncies and jurisdictions. The physical improvement p lan should also id enti fy locations in need of bicycle parking and storage fac i lities . In genera l, provisions for bicycle pa rkin g sho uld be considered at all major traff ic generators and at transit stations and bus stops to enco ur age intermoda l travel. Selection of a Bicycle Facility Many fac tor s should be co nsidered in deter mining the appropriate bicy- cle faci lity type , l ocation and priority for imp lementation. In addition to the guidelines below, the Federal Highway Administration provides gu idance on facility se lect io n in the 1994 pub li cation Se lectin g Road- way Design Treatments to Accommodate Bicycles .11 ') Ski ll Level of Users-As described in the sect ion on Bicycle Users ear li er i n this chapte r, co nsideration should be g iven to the sk ill s and preferences of the types of bicyclists who will use the fac ility. Fac i liti es near schoo l s, parks and residential neighborhoods are l ike ly to attract a hi ghe r percen tage of basic and chi ld bicyclists than advanced bicyclists. :) Motor Vehicle Parking-Th e t urnover and density of on-street parking can affect bicyclist safety (e.g., opening car doo rs and cars leaving parallel parking spaces ). Diago nal and perpendicular park- guide for the development of bicycle facilities 11 ing arra ngements are not compatib le w ith bicycle facilities be- cause of restricted sight distance and t he related potential fo r bicycle-motor ve hicl e conflicts. They sho uld be avoided whe reve r possib le. 0 Barriers-In some areas , t here are p hys ical barr iers to bicycle trave l caused by topographical features , such as rivers, railroads, freeways or other impedime nts. In such cases, prov idin g a fac ility to ove rcome a bar ri er can c reate new opportu nities fo r bicycling. ) Crash Reduction-The reduction or p revent ion of bicycle cras hes (i .e., bicycle/motor vehicle, b icycle/bicycle, bicycle/pedest ria n and sin gle bicycle c rashes) is im portant. Therefore, the pote nti al for reducing crash problems through t he i m prove ment of a fac ility should be assessed. Plans for construct in g new bicycle faci liti es should be reviewed to identify and reso l ve potentia l safety issues . 0 Directn ess-Partic ul ar ly for util itaria n bicycle trips , faci liti es shou ld connect traffic generato rs and shou ld be l ocated al ong a di- rect l i ne of trave l that is conve ni ent for use rs. 0 Access ibility-In locating a b icycle fac ility , consi deration sho uld be g ive n to the provision fo r frequent and conven ient bicycle ac- cess , especially in residential areas. Adequate access for eme r- gency, maintena nce and se rvice ve hi c les sho uld also be conside red. Othe r major traffic generato rs such as ed ucationa l fa- cilities, office b uildin gs , shopp in g areas, parks and muse um s sho uld also be co nsid ered w hen eva lu at in g bicycle accessibi lity. ) Aesthetics-Scenery is an important conside ration along a fac ility, particu l ar ly for a fac ility that w ill serve a primarily rec reationa l pur- pose . Trees can also provide coo ler riding conditio ns in sum mer and ca n provide a windbreak. O Perso nal Safety/Secur ity-The potential for crim in al acts agai nst bicyclists, especia l ly along isolated sha red use pat hs, and the pos- sibility of theft or va nd al ism at parking locat ions , sho ul d be cons id- ered . ) Stops-B icyclists have a strong inherent desire to m aintain mo- mentum. If bicycl i sts are required to make frequent stops , they m ay avoid the route or disregard t raff ic co nt ro l devices . . ) Conflicts-Different types of faci liti es introduce different types of conflicts . Facilities o n the roadway can resu lt in co nfli cts betwee n bicycl ists and motorists. Shared use pat hs can involve conflicts be- tween bicyclists, horseback riders, skaters, runn ers and pedestr ians on the facility. Co nfli cts betwee n bicycl ists and motorists may al so occur at highway and driveway in tersect ions . .) Mainte nance-Des igns wh ich facilitate and simp lify m aintena nce will improve the safety and use of a faci lity . A local or regio nal bikeway maintenance program is esse nti al. Planning 12 guide for the development of bicycle facilities Planning 0 Pavement surface quality-Bikeways should be free of bumps , hol es and other surface irregulari t ies if they are to attract and satisfy th e needs of bicycl ists. Utility covers and dra in age grates should be at grade and, if possible, outside the expected path of trave l. Rai 1- road c ro ssings sho uld be imp roved as ne cessary to provide for safe bicycle c ro ssings . 0 Truck and Bus Tr affic-Because of the ir width, high-speed trucks , buses, motor homes and trail ers can ca us e spec ia l prob l ems for bi- cycl i sts . Where bus stops are located a lon g a bicycle ro ute, con- flicts w ith bus loading and unloading and pavement deterioration, suc h as asphalt pavement shovin g, may a lso be prob lem s. 'J Traffic Vo lum es and Speeds-For faci liti es o n ro adways, motor ve- hicl e traffic volu m es and speeds must be cons id ered al o ng with the roadway width . Commuting bicycli sts frequent ly use art er ia l st reets because they minimize d e lay a nd offer contin uity for long trips. If adequate width for all veh icl es is ava il able o n the more heav il y traveled stree ts , it can be more d es irab le to improve such st reets than adjace nt st reets . When this i s not possible, a nearby paral le l street may be improved fo r b icycli sts, if stops are minim al and other route co ndition s are adeq uate . When such a parallel fa- c ility is improved, ca re mu st be taken th at motor veh icl e traffi c is not diverted . While in exper ie nce d b icyclists prefer more l ightly-traveled stree ts , it should be rem embered that preferred ro utes m ay cha nge over time as ski ll leve l s c hange . 0 Bridges-Bridges ca n se rv e an important fun ction by providing bi- cycle access across barri ers . However, some bridge features re- st ri ct bicycle access and /or create unfavo rable co ndition s for bicyclists. The most common of these are curb-to-curb widths t hat are narrower than the approach roa dways (especia ll y where com- bined with relatively steep grades), ope n g rated metal decks found on m any spans , low railin gs or parape ts, a nd certain types of ex- pansion joints suc h as finger-type jo ints, th at can cause stee rin g d if- ficu I ties . 0 Int e rsection Co nditions-A high propo rtion of bicycle cras hes oc- c ur at inte rsections. Fac iliti es should be selected so as to minimize the number of c ro ss in gs, or intersections shou ld be imp roved to re- duce crossing confl ict s. At-grade inte rsections on high-volume (or hi gh-sp eed) roadways and mid -b loc k c ro ssi ngs sho uld be ana- l yze d w ith bicyclists ' needs in mind to determine the most app ro- priate crossing design treatments . 0 Costs/Fundin g-Fac ility se l ection norma ll y will involve a cost anal ysis of a lternat ives . Fun ding ava il ability ca n limit the a lterna- tives ; however, it is ve ry important that a l ack of funds not result in a poor ly designed or constructed fac ility. Th e decision to impl e- ment a bikeway p l an should be made with a conscious, long-term com mitme nt to a proper level of maintenance. When funding is limited, emphas i s sho uld be given to l ow-cost improvements such as bicycle parking, removal of ba rriers and obstru ctions to bi cycle guide for the development of bicycle facilities 13 trave l , and roadway im prove m ents. Fac ility select ion should seek to max im ize user benefits per doll ar f und ed . 0 State and Loca l Laws and Ordinances-Bicycle programs mu st re- flect state and loca l laws and ordinances. Bi cycle faci I ities mu st not enco urage or req uire bi cycl i sts to operate in a mann er that is in - cons i stent with th ese l aws and ordinances. Education Programs for Bicyclists and Motorists Bicyclist and motorist ed ucatio n programs are key ingredients to bui ld- in g a successf ul bicycle transportat ion syste m and foste rin g th e growth of bicycle use in a co mmunity. A primary reaso n i s the great amount of mi s- in formation that h as sp rea d abo ut bi cycl in g. Edu cat ion programs ca n hel p to dispe l the myths, encou ra ge co urteo u s and l awfu l be hav ior amo ng motorists and bicyclists of all ages, and enh ance th e ski ll leve l of bicyclists and moto rist awa reness, thus lead in g to a reduct io n in cras hes. The education p rogram ca n be adm ini ste red thr ough a number of d iffer- ent agencies and interes t groups , suc h as po li ce depa rtm ents , schoo l s, libraries , b icycle clubs , and parks and recreation departments . Th ere are four prima ry audi ences for bicycle safety ed ucation and awareness effo rts. For eac h gro up, an ed ucat io n program ca n st ress basic messages th at focus o n the most freque nt ca uses of cras hes and injury. Th e fo ll ow in g represe nt messages and sk ill s th at sho uld be stressed for each gro up: Young Bicyclists: '.) How to ri de in a stra ight lin e w ithout wobb l in g or swerv in g 0 Importan ce of stop pin g, look in g and y i elding befo re ente rin g or cross in g a roadway ) Importan ce of ridin g with traffic (o n the ri ght-hand sid e of th e road), rath er t han agai nst traffic 'J How to scan beh ind for traffic before mov in g or tu rnin g l eft :) Importance of helmet use 0 Impo rt ance of using hand signal s :) Know ledge and und erst andin g of traffic co ntrol dev i ces :) Methods of crossi ng intersections Parents of Young Bicyclists: .) Age and developmental facto rs in bicycle safety Planning 14 guide for the development of bicycle facilities Planning ) Commo n cause of cras hes ) Im portance of riding with traffic (on the r ight-hand side of the road ), rather than against traffic ) Driveway intersection sig ht distance problems ) Importance of helmet use for themse l ves and their ch ildren 0 Importance of sett in g a good example Adult Bicyclists: ) Bicycles are veh icl es and should be operated according to traffic laws ) Im portance of riding with traffic (on the r ight-hand sid e of the road ), rather than against traffic :) Imp ortance of helmet use ) Im portance of using lights and reflectors at night ) Imp ortance of using hand signals ) Importance of courtesy toward other road use rs, motorists and pe- destrians 0 Knowledge and understanding of traffic control devices Motorists: ) Bicycles are vehicles and have legal rights to use the roadway ) Skil l s for sharing the road with b i cyclists ) Im proper turning movements that enda nger bicyclists (do not turn in front of bicyclists) ) Importance of courtesy toward other roa d users including bicy- clists and pedestrians guide for the development of bicycle facilities 15 Chapter 2 Design Design of new bicycle faci l ities, as we ll as improvements to existing fa- ci lities , is an ongoing process that shou ld be co nsi stent with a comprehe nsive plan co nsid ering the different bicycle use rs, exist in g conditions and comm u nity goa l s. A w id e range of faci lity im proveme nts can enhance bicycle tra nsportat ion. An improvement ca n be simp le and in volve mi nim al design co nsiderations (e.g ., changing d rain age grate in - lets) or it ca n be more exte nsive (e.g ., providing a shared use path). For example, i mproveme nts suc h as bicycle l anes depend on the roadway's desig n . On the other hand, shared u se paths are located on independe nt ali gnments; consequently, their design depends on many factors , incl ud- in g right-of-way , avai l ab le funding, topography and expected use . A commun ity's overa ll goa l s for transportation improve m ents shou ld in - clud e prov ision s for b icy cl e trave l. Through app ropriate p l anning and design, ge neral im prove ments for moto r vehicles can also be designed to enh ance bicycle trave l. For all roadways w here bicycle travel is per mit- ted, plan ning and des ign shou ld consider provisions for bicycli ng. Roadway pro j ects that ex tend nea r or intersect existi ng or pla nn ed shared use path s shou ld inclu de ca reful analys is and des ign measures t o ensure the co ntinued access and safety of path users . Pub li c in volveme nt i n the form of public meet in gs , hearings or bicycle adviso ry groups is en- couraged du rin g the plan nin g and design processes . G ui de li nes are presented in this chap ter to help design and im p lement bi cycle faci I iti es that acco mm odate the operat in g charac teri stics of bicy- cles as defi ned in this guid e. Mod ificat ion s to facilities (e .g., widths, c urve radii, su perelevations, etc.) that are necessary to accommodate ad ult tricycles, bicycle trail ers , and other special purpose human- powered ve hicl es and accessories should be m ade in acco rdance w ith t he expecte d use, using so un d engineering judgment. This chapter has been organized aro und the various classifications of bikeways: ..) Shared Ro adways ) Signed Shared Roadways 0 Bike La nes :) Shared Use Paths _) Othe r D esign Cons id erations Where gu id elin es over lap across classifications, reference is made to t he appropriate section to elimin ate repeating text. Design 16 guide for the development of bicycle facilities Figure 2. Example of a Sh ared Use Ro adway Design Shared Roadways Shared Roadways To va rying extent, bicycles wi ll be used o n all hi ghways w here t hey are pe rm itted . Bi cycle-safe des ign pract ices, as desc ri bed i n t hi s gu ide, sho u ld be fo l lowed d u rin g initi al roadway des ign to avoid cos t l y sub se- q uent i mprove ments . Beca use most exist in g hi ghways have not been des igned w it h b icycle trave l in mi nd, roadways ca n often be improved to mo re safe ly acco m modate b icycle traffic. D es ign features t hat ca n m ake roa d ways mo re co m pat ibl e to bi cycle trave l in clu de b icycle -safe d ra in - age grates and br idge expa nsio n jo i nts, improve d rai l roa d c ross in gs, smoot h pave ments, adeq uate si ght dista nces, and signal timi ng and de- tec tor systems that respond to b icycles. In add iti o n, more cos t ly shou lder i m p roveme nts and w ide c urb l anes can be co nside red. A lso see C hapte r 2, O th er Des ign Co nside rati o ns. W idth is t he most critica l var iabl e affect ing th e ab i I ity of a roa dway to ac- com modate b icycle t raffic. I n o rder for b icy cl es and motor ve hicl es to share th e use of a roadway w ith o ut com pr o mi sin g t he l eve l of se rv i ce and safe ty fo r e ith er, t he fac ili ty should prov ide suff ic i ent pa ved w idth to acco mm odate both modes . T h is width ca n be ac h ieved by pr ov idin g w ide o utside l anes or pave d sho ul ders. Paved Shoulders Adding or i mproving pave d sho u lders ofte n ca n be t he bes t way to ac- co mm odate b icycl ists i n rur al areas and benefi t motor ve hicl e tr aff i c. Paved sho ul ders ca n exte nd th e service li fe of th e road surface sin ce edge d eter io rat io n w il l be signi f icant ly reduced . Paved sho ul ders al so prov id e a b rea k-down area fo r motor veh icl es. Where fu ndin g i s I i m ite d , ad ding o r i mprovi ng sho uld ers on up h i ll sec t ion s w i l l give slow-mov in g bicycli sts needed maneuver in g space and w ill dec rease co nfli cts w it h fas ter mov i ng motor ve h icle traffic. Pave d sho uld ers sho u ld be at least 1.2 m (4 fee t ) w ide to acco mm oda te b icy cl e trave l . H oweve r, w here 1.2-m (4-foot) w idths ca nn ot be ac hi eved , any addit io nal sho uld er w idth is better t han no ne at all . T he measure ment of usab le sho u lder width sho ul d not i ncl ude th e w idth of a gutter pa n, unl ess t he pa n w idth is 1.2 m (4 feet) o r grea ter. Should er w idth of 1 .5 m (5 feet) is rec omm ended fro m th e face of guardr ai l , c urb o r ot her roa dside barr iers. It is des i rab l e to in c rease t he w idth of sho ul - de rs w here h ig her bicycle usage is expecte d . Ad d it i o nal sho u lder wi dth is also des ir ab le if moto r ve hicl e speeds excee d 80 km/h (S O mph ), o r t he pe rce ntage of t ru c ks, b uses and recre at i o nal vehicl es is hi gh, o r if sta ti c o bstru cti o ns ex ist at t he r ight sid e of the roa dway. In genera l , AAS HTO 's reco mm endatio ns fo r sho ul der w idth (as de- sc ri bed i n A Po licy o n Geom etric Design o f Hig h ways and Stree ts (G ree n Book 1)) are t he best guid e fo r bi cycles as we l l , sin ce wide r shou lders are reco mm end ed on heav i l y tr ave led and hi gh-s pee d roa ds and tho se ca r- ry in g l arge num bers of tr uc ks. H oweve r, i n o rd er to be usa bl e by b i cycl ists t he sho ul der m ust be paved. guide for the development of bicycle facilities 17 Rumble strips or raised pavement markers, where insta ll ed to discourage o r warn motorists they are driving on the shou lder, are not recom- mend ed w here sho uld ers are used by bicyclists unless there is a minim um clear path of 0.3 m (1 foot) from the rumble st rip to the trav- eled way, 1 .2 m (4 feet) from the rumble st rip to the outside edge of paved shoulder, or 1 .5 m (5 feet) to adjace nt guardr ai l , c urb or other ob- stacle. If ex ist in g conditions precl ud e ac hi ev in g the minimum desirable clearance , the width of the rumble str ip may be decreased or other ap- propriate altern ative so lutions shou ld be co nsid ered. Increased Lane Width Wid e curb l anes for bicycle use are usually preferred where shou ld ers are not provided , suc h as in restrictive urban areas. On highway sect ion s without designated bikeways, an outside or c urb l ane wider than 3.6 m (12 feet) ca n better accom modate both bicycles and motor vehicles in the same lane and th us is beneficial to both bicyclists and motorists . In many cases where there is a wide curb l ane, motori sts will not need to change lanes to pass a bicyclist. Also, a wide curb l ane provides more maneuvering room whe n drivers are exiting from driveways or in areas with limited sight distance. In genera l , 4 .2 m (14 feet) of usable l ane width is the recomme nd ed width for shared use in a wide curb l ane. Usable width norm all y would be from edge st rip e to l ane str ipe or from the lon g itudinal joint of the gut- ter pan to lan e str i pe (t he gutter pan should not be included as usable width ). On st retches of roadway with steep grades where bicyclists ne ed more maneuvering space, the wide c urb lan e should be slightly wider where practicab le [4 .5 m (15 feet) is preferred). The 4.5-m (15-foot) w idth may also be necessary in areas where drainage grates, raised re - fl ectors on the ri ght-hand sid e of the road , o r on-street parking effective ly reduce the usable width. With these exceptions in mind, widths greater than 4.2 m (14 feet ) that exte nd continuousl y alon g a stretc h of roadway ma y encourage the undesirable operation of two motor vehicles in one lane, espec ially in urban areas, and therefore are not reco mm ended. In situ at ions w here more than 4.5 m (15 feet) of pavement width exists, co nsid eratio n should be give n to st ripin g bike lan es or shoulders . Restripin g to provide wide c urb lanes may also be cons id ered on so me existing multi-lane faci liti es by making the remaining travel l anes and left-turn lanes narrower. This should only be considered after carefu l re- view of traffic characteristics alo ng the corr idor and supported by a documented engineering anal ysis based on app li cab le design criteria. On-Street Parking On-street parking increases th e potential for co nflicts between motor ve- hicl es and bicyclists. The most commo n bicycle riding location on urban roadways is in the area between parked ca rs and movin g motor vehicles . Here, bicyclists are sub j ected to ope nin g car doors, ve hicl es exiti ng parkin g spaces, extended mirrors that narrow the travel space , and ob- Design Shared Roadways 18 · \e tac\\\t\es guide for the deve\opment of b\C\f C Design Shared Roadways sc ured views of intersecting traffic. Therefore , 3.6 m (1 2 feet ) o co mbined bicycle travel and parking w idth shoul d be the minim um co n- side red for this type of shared use . Pavement Surface Quality The smoothness of the ridin g surface affec t s the comfort, safety and speed of bi cyc li sts. Pavement surface irreg ul ari ties can do more than ca use an unpl easant ride. Pavement surfaces shou ld be smooth, and t he pavement should be uniform in width. Wide cracks, joints or drop-offs at the ed ge of tr ave led way para I l el to the direct io n of travel can trap a bicy- cle w hee l an d cause loss of control ; holes and bumps ca n cause bicyclists to swerve into th e path of motor ve hicl e traffic. In addition, a reduction in th e operatin g speed of the b icyclist be low a comfo rt ab le leve l res ults in less stabi li ty of the bicycle. As pavements age it may be necessa ry to fill joints o r crac ks, adjust uti li ty covers or eve n overlay the pavement i n some cases to make it suitab le for bicycling. Drainage Inlet Grates Drainage inl et grates and utility covers are po tential obstructions to bicy- clists. Th erefore, bicycle-safe grates sho u Id be used , and grates and cove rs should be loca ted in a m anner whic h w ill minimize severe and/or fre qu ent maneuverin g by th e bicyclist. W hen new highway fac iliti es are co nstructed , c urb opening inl ets should be cons idered to minimize the number of potenti al obst ru c tion s. Dra i nage inl et grates and utility covers should be p laced or ad ju sted to be flush w ith the adjacent pavement sur- face. Drain age inl et grates w ith slots parallel to the roadway, or a gap between the fr ame and the grate, ca n trap the fro nt wheel of a bicycle, ca using l oss of steer in g co ntrol. If the slot spac i ng is wide enough , narrow b i cycle w hee l s ca n drop into the grat es. Conflicts with grates may result in seri- ous dama ge to th e bicycle wheel and fra me and/or injury to the bicyclist. These grates shou Id be rep laced with bicycle-safe, hydra u I ical ly- effic ient ve rsio ns. When this is not immed iate ly possible, a temporary co rr ect ion is to we ld stee l c ro ss straps or ba rs perpendicular to the paral- l el bars at 100-mm (4-i nc h) center-to-ce nter maximum spac in g to provide a max imum safe opening betwee n str aps . While id entifyi ng a grat e with pavement markin gs would be acceptable in some situ at ion s, as indicated in the MUTCD 2 , bar grates wi th bars par - all el to th e direction of travel deserve spec ial attention . Because of the se rious co nse qu ences of a bicyclist missi ng the pavement marking in the dark or being forced over suc h a gra te in let by other traffic, t hese grates should be physically corrected, as described above, as soon as p ractica- ble afte r th ey are ide ntifi ed . guide for the development of bicycle facilities 19 Signed Shared Roadways Signed shared roadways are those that have been identified by signi ng as preferred bike routes . There are several reaso ns for des ignating signed b i ke routes : a. The route provides continuity to other bicycle faci l ities suc h as bike l anes and shared use paths . b . The road is a common route for bicyclists through a high de- mand corridor . c. In rural areas, the route is preferred for bicycling due to low mo- tor vehicle traffic volume or paved shou lder avai lability . d. The route extends along local neighborhood st reets and co ll ec- tors that lead to an interna l neighbo rh ood desti nat i on such as a park , school or commercia l district. Bik e route signs may also be used on streets w ith bike la nes, as well as on shared use paths. Re gard less of the type of facility or roadway where t hey are used , it is recommended that bike route signs include destinatio n in- formation , as shown in Figure 4 . Signin g of shared roadways indicates to cycl i sts t hat the re are partic ul ar advantages to usin g t hese routes compared to alternate routes. Thi s means the responsible age ncies have taken action to ens ure these ro utes are suitable as shared routes and wil l be maintained . Th e following criteri a should be considered prior to sign in g a route: a. The route prov ides through and direct travel in bicycle-dema nd cor ridors. b. The route co n nects discont in uous seg ments of shared use pa th s, bike lanes and /or other b i ke routes . c. An effort has been made to adjust traffic contro l devices (e.g., stop signs , signa l s) to give greater p ri ority to bicyclists on t he route , as opposed to alternative streets. This could inclu de placement of bicycle-sensitive detectors where bicyclists are ex- pected to stop . d. Street parking has been removed o r restricted i n areas of critica l width to provide i mproved safety. e. A smooth surface has been provided (e.g., adjust uti li ty cove rs to grade, install bicycle-safe drainage grates, fill potholes , etc.) f . Mai nten ance of the route wil l be suff icient to prevent accum ul a- tion of debris (e.g., regular street sweeping). g. Wider curb lanes are provided compa red to para ll el roads. Design Signed Shared Roadways 20 guide for the development of bicycle facilities Figure 3. Example of a Signed Shared Roadway Design Signed Shared Roadways h . Should er o r c urb l ane widt h s ge nerally mee t or excee d w idth re- q uirements in cl ud ed und er Shared Roa d ways, page 17. Designating Sidewalks as Signed Bikeways In ge neral , th e d es ignated use of sidewa l ks (as a signed share d fac il ity) fo r bi cy cl e tr ave l is un sa ti sfac tory . (Se e Undesirability of S idewa lks as Sh are d Use Path s, p age 58.) It i s impo rt ant to recog ni ze that th e develo pm ent of ex treme l y wi de side- wa lk s does not necessa ril y add to t he safe ty of sidewa l k bicyc le t rave l , si nce w id e sid ewa lks enco urage h ighe r spee d bi cycle use and in crease po tenti al fo r co nfli ct s w it h motor vehicl es at intersect ions , as we ll as with pe des tri ans and fi xe d o bj ec ts. Si dewa lk bikeways sho uld be con sidered o nly un de r certa in limited c ir - c um st ances , suc h as: a. To prov id e bikeway co ntinui ty al o ng hi gh speed o r heav i ly trav - e led roa dways hav in g in adeq uate space for b icycli sts, and uninterru pted by dri ve w ays and i ntersec ti o ns fo r l o ng di st ances. b . O n l o ng, narr ow brid ges. I n suc h cases , ram ps sho u ld be i n- stall ed at th e sid ewa lk approac hes . If app roac h b ikeways are t wo-wa y, sid ewa lk fa c ilit ies al so should be two-way. W heneve r sid ewa lk b i keways are estab li shed , unn ecessa ry o b stacles should be remove d. W heneve r bi cyclists are direc ted fro m signed shared roa dways to sid ewa l ks, c urb c uts sho ul d be flush w ith t he stree t to ass ure t hat bi cy cli st s are not subj ec ted to prob l em s as soc iated w it h c ross in g a ve rti ca l lip at a fl at angle. Curb c u ts at eve ry in tersec ti o n are necessa ry, as we ll as bikeway yie ld o r sto p sig ns at u nco ntro ll ed in tersec tion s. Cur b cu t s sho ul d be w id e eno ugh to acco mmodate ad ul t t ri cycl es and two-whee l bi cycl e tr ail ers. In res id ent ia l areas, sidewa l k ridin g by yo un g c hil d ren is co mm o n. With lowe r bi cy cl e speeds and lower cross stree t auto speeds , potenti al co n- fl ict s are so mewhat lesse ned , bu t sti l l ex ist. N eve rth eless, thi s type of sid ew alk b icy cl e use i s acce pted . It is i nappropri ate to sign th ese fac ili - ti es as bi cy cl e routes . In ge neral , b icycl ist s shou l d not be encourage d thro ugh signin g to ri de fac i l iti es th at are not des igned to acco mm od ate bi cycl e trave l. Signing of Shared Roadways Ty pi ca l bi cy cl e ro ute signin g i s shown i n Fi gure 4. Fo r t hese signs to be more fun c ti o nal, suppl emental destin atio n p lates sho ul d be pl ace d be- nea th th em wh en loca ted alon g ro utes lea din g to hi gh dem and des tin at ion s (e .g., "To D o wntown ", "To St at e Col lege ", et c.). guide for the development of bicycle facilities 21 Th ere are in st ances w here it i s necessa ry to sign a ro ute to di rec t b icy - cli sts to a logi cal destin ation ; howeve r, th e route d oes not offe r any of th e abo ve signed sh ared ro adway c riter ia. I n su c h c ases, t he route sho u l d not be signed as a b i ke route, alth o ugh des t in ation sign i ng m ay be adv i sab le. A typi c al appli ca ti o n of des tination signin g wo u ld be w here bi cy cl ist s are direc ted off a h ighway to byp ass a sec tio n of fr ee way . Sp ec i al signs wou ld be p l ac ed t o gui de b icy cl ist s to th e nex t l og i ca l des t i nati o n, m uc h as motori sts woul d be d i rec ted if a h ighway deto ur we re required . In ur- ban areas, signs ty pi ca ll y wou ld be pl ace d eve ry 500 m (approx imate ly every 1/4 m i le), at all tu rn s, and at major signal ized intersect io ns . • 11111 = M7 series sign • 01 1-1 llllil O ptio nal Des t inati on Signi ng In urban are as , signs shou ld be placed every 500 m (approx. 1/4 mil e), at every turn , and at all sig na lize d intersectio ns. Figure 4. Typical Signed Shared Rout e Signing Design Signed Shared Roadways 22 guide for the development of bicycle facilities Figure 5. Bic ycle Lane Markin gs Design Bike Lanes Bike Lanes Bike lanes can be incorporated into a roadway when it is des i rab le to de- lineate avai lable road space for preferent ial use by bicyclists and motorists , and to provide for more predictable movements by each. Bike lane markings, as exemplified in Figure 5, can increase a bicyclist's con- fidence in motorists not straying into their path of trave l . Likewise, passing motorists are less like ly to swe rve to the left out of their lane to avo id bicyclists on their r ight. A lso see Chapte r 2, Other Des ign C r iteria , for additional information w hi ch applies to b i ke lanes. Drainage grates , railroad crossings , traffic contro l devices , etc., need to be eva l uated and upgraded if necessary for bicyc le use . Bike lanes should be one-way facilities and ca rry bike traffic in the same direction as adjacent motor ve h icle traffic. Two-way bike lanes on one side of the roadway are not recommended w hen they result in bicycles riding against the flow of motor vehicle traff ic. Wrong-way riding is a major cause of bicycle crashes and violates the ru les of the road as stated i n the UVC 3 . Bicycle-spec ific wrong-way sign i ng may be used to dis- courage wrong-way trave l . However, there may be special situat ions where a two-way bike lane fo r a short distance can eliminate the need for a bicyclist to make a doub le crossing of a busy street or travel on a side- walk. This should only be considered after careful evaluat i on of the relative risks and shou ld be we ll documented in t he project f il e. On one-way streets , bike lanes should genera l ly be placed on the right side of the street. Bike lanes on the left side are unfamiliar and unex- pected for most motorists . Th is should only be considered when a bike lane on the left will substant i all y decrease t he n umber of conflicts, such as those caused by heavy b us traffic o r un usuall y heavy turn i ng move- ments to the right, or if there are a significa nt number of left-turning bicyclists. Thus, left-side bike lanes should on ly be considered after care- ful eva l uation. Similarly, two-way b i ke lanes on the left side of a one-way street cou ld be co nsidered w ith a sui tab le separatio n from the motor veh icle traffic after a co m p lete enginee rin g study of other alterna- tives and relative risks . Bike Lane Widths To examine the width requi rements for bike lanes , Figure 6 shows four typica l locations for such fac i l it ies in relation to the roadway . For road- ways with no curb and gutter, the minimum width of a bike lane shou ld be 1.2 m (4 feet). If park i ng i s pe rmitted , as i n Fig u re 6(1 ), t he b i ke lane shou ld be p laced between t he parking area and t he travel la ne and have a minimum width of 1 .5 m (5 feet ). Where parking is perm itted but a parking stripe or stalls are not uti l ized , the shared area shou ld be a mini- mum of 3.3 m (11 feet ) without a curb face and 3.6 m (12 feet) adjacent to a curb face as shown in Fig ure 6(2 ). If the pa rk i ng volume is substa ntia l or turnover is high, an add it io nal 0.3 to 0.6 m (1 to 2 feet) of width is de- sirab le. guide for the development of bicycle facilities 23 Bike lanes should neve r be placed betwee n th e par kin g lane and c urb lane. Bike la nes betwee n th e c urb and park in g l ane ca n c re ate obsta cles for bi cyclists from ope nin g ca r doors a nd poor visibi lity at intersect i on s and driveways and they prohibit b i cycl i sts from making l eft turns. Fi gure 6(3) d epi cts a b i ke l ane a lon g t he outer portion o f an ur ban c urbed street where parkin g is pro hibited. Th e reco mm end ed w idth of a bike l ane i s 1 .5 m (5 feet ) from th e face of a curb or guardrail to t he bike l a ne str ipe. Thi s 1 .5-m (5 -foot) w idth should be suffic ient in cases where a 0.3-0 .6 m (1-2 foot) wi d e co ncrete gutter pan ex i sts, g ive n that a minimum of 0.9 m (3 feet) of rid ab le surfa ce is provided, a nd the l o ngi tudin a l joint betwee n the g utte r pan and pave- m ent surface is smooth. Th e width of the g utter pa n shoul d not be in clud ed in th e meas urem e nt of t he rid ab le or us ab le surface , with th e possibl e exception of tho se co mmuniti es th at use a n extra w id e, sm ooth l y paved g utter pan that is 1 .2 m (4 feet) w id e as a b i ke la ne. If th e joint is not smooth , 1 .2 m (4 fee t) of rid abl e surface sho u ld be provided. Sinc e bicycl ists usuall y tend to ride a di sta nce of 0 .8-1 .0 m (32 -40 in c hes) fro m a curb face, it i s ve ry importa nt that th e pavement surface in thi s zo ne be smooth and fr ee of st ru c tures. Dra in inl ets a nd ut ili ty cove rs th at exte nd in to th is area m ay ca use bicyclists to swerve, and have the ef- fect of reduc in g the usa bl e w idth of th e l ane. Where t hese struct ures ex ist, th e b ike l ane w idth m ay nee d to be ad ju sted acco rdin g l y. Fi gure 6(4) d epi cts a bike lane on a roadway in an outly in g area w ithout c urbs and g utters . This location i s in an und eve loped area where infre- quent pa rk in g is handl ed off th e pave m e nt. Bike l anes should be loca ted within the lim its of the paved shou lder at th e o utsid e ed ge. Bike l anes m ay have a minimum width of 1 .2 m (4 feet ), w here the area beyo nd th e pav ed shou ld e r ca n p rov id e addition a l m aneuverin g w idth . A w idth of 1 .5 m (5 fee t) or g reater is prefe rab l e and addition a l w idth s are des irab le where substa nti a l tr uc k t raffic is prese nt, or wh ere motor vehicl e spee d s exceed 80 k m/h (50 mph ). A bike la ne should be de l ineated from the m otor ve hi c le trave l lanes with a 150-mm (6-in c h) so lid w hite lin e. Some jur isdiction s have use d a 200-mm (8-in c h) lin e for ad d ed d ist i ncti o n . A n ad ditional 100-mm (4 -in ch) so l id white li ne ca n be p l aced between th e parking l ane and th e bike lane (see Fi g u re 7). Thi s seco nd line w ill e ncourage pa rkin g closer to th e curb, provid in g add ed sepa ration from motor ve hicl es, a nd w here park in g is li g ht it ca n di sco u ra ge motori sts from usin g t he bike l ane as a thro ug h trave l lane. Bik e l anes shou ld be provided w ith ade quate drai nage to preve nt ponding, was houts, debris acc umul at ion a nd o th er pote nti a ll y haza rd- ous situat ions for bicycl i sts. The drainage g rates should be bi cycle-safe. Wh en an imm ediate rep lace m e nt of a n in co mpat i bl e g rat e i s not poss i - b le, a temporary co rr ec tion of we ldin g thin m eta l str aps across th e grate s perpendicu l ar to th e dra in age sl ots at 100-mm (4-in c h) ce nter-to -ce nter spa c in g sho uld be co nsid ered. Design Bike Lanes 24 guide for the development of bicycle facilities Design Bike Lanes 1 Parking Stalls or Optional 100 mm (4 in) Solid Stripe(*) -i ! + 150 mm (Sin) Solid White Stripe --i = - .. 1.5 m (5 ft) Min . B i ke Lane Motor Vehicle Lanes ~-14--~-::-"~-L.;,J · .· .. •The optional so lid white stripe may be advisable where stalls are unnecessary (because parking is light) but there is concern that motorists may misconstrue the bike lane to be a traffic lane . (1) ON-STREET PARKING L vort ;~1 rum ~- I Bike Parking L a n e .. + 150 mm (6 in) Solid White Stripe -i Motor Vehicle Lanes .. 3.6 m (11 ft) Min . (*) *3 .9 m (13 ft) is recommended where there is substantial parking or turnover of parked cars is high (e .g . commercial areas). (2) PARKING PERMITTED WITHOUT PARKING STRIPE OR STALL Lane R~IOOruro~ ~ Bike Lane I Parking · · 1 .. .. 3.3 m (11 ft) Min. (*) (With Curb an d Gutter ) (Without Curb and Gutter) ~IY~150mm(6in)SolidWhiteS tri p e t ~ .. 1.5 m (5 ft) Min . Bike Lane Rum bl e Motor Veh ic le Lanes (3) PARKING PROHIBITED 1.2 m (4 ft) Min . Bike Lane ! Stri p s A~1 50 mm (6 in) Soli d W h ite Stripe ---i l.2m 14 .ft) Min . Bike Lane Motor Vehicle Lanes (4) TYPICAL ROADWAY IN OUTLYING AREAS PARKING PROTECTED *If rumble strips exist there should be 1.2 m (41!) minimum from the rumb le stri ps to the outside edge of the shou lder. Figure 6. Typical Bike Lane Cross Sections 1.2 m (4 ft) Min . B i ke Lane guide for the development of bicycle facilities 25 A smooth r iding surface should be provided a nd utility cove rs shou ld be ad ju sted flus h with the surfa ce. Raised pave ment ma rkin gs and ra ise d barriers can ca use steering d iffi - c ulties for bicyclists and shoul d not be used to de li neate bi cycle l anes . Bike Lanes at Intersections Bike l ane stripin g should not be installed ac ro ss any pedestrian c ross- walks, and, in most cases , shou ld not conti nu e through any street inter- sect ions . If there are no painted c ro sswa lks, the bike lane strip ing should stop at the nea r side c ro ss street p rop e rt y lin e ex te nded and th en res um e at the far sid e property lin e exte nd ed . Th e o nl y except ion to this cavea t mi g ht be the extensio n of dotted g uidelines through part i c ul arl y com ple x intersectio ns or multi-la ne rounda bouts. The sa me bike l ane st ri p in g c ri - ter ia apply whether park in g is pe rmitted or prohibited in th e vici nity of th e intersect ion. At signa li ze d or stop -co ntro ll ed intersectio ns with rig ht-turn ing motor vehicles, the so l id str ipin g to the ap proa ch shou ld be repl aced w ith a broken l ine w ith 0 .6-m (2-foot) dots and 1.8-m (6-foot) spaces. Th e le ngth of t he broken l ine section i s usuall y 15 m to 60 m (50 feet to 200 feet). Since there are usually sm all vo lum es of right-turn ing motor veh icles at non signal iz ed m inor intersectio ns w ith no stop co ntro ls , so lid b ike l ane st ripin g ca n co ntinu e all the way to th e crosswa l k on t he nea r side of t he inte rsectio n . Howeve r, if th ere is a b us stop or high rig ht-t urn vo lum e, th e 150-mm (6-inch) so li d lin e sho uld be rep l aced w ith a broken line with 0.6-m (2-foot) dots and 1 .8-m (6-foot) spaces for t he l ength of th e bu s stop . The bike lane stripin g should resu me at the o utsid e line of th e c ro sswalk o n the far sid e of the inte rsec ti on. (See Figure 7.) If a bus sto p is located on a far sid e of the intersection rath e r than o n a near side app roach, the so li d wh ite lin e can a lso be rep l aced with a bro- ken li ne for a d istance of at least 24 m (80 feet) fr o m the crosswalk o n th e fa r side of t he in tersectio n. Fi gure 7 i llu strates typi cal bike l ane str ip i ng at interse c tions without bus stops , at intersections with near sid e bus stop s (r ig ht-h and sid e of t he f igure) and at intersec tion s w ith fa r side bus sto ps (left-hand sid e of the f i gure). At T-intersec tion s w ith no painted c rosswalks, th e bike l ane stripi ng on th e side ac ro ss from the T-intersect io n should co ntinu e t hro ug h the inter- section area with no break . If there a re pai nted crosswa lk s, th e b ike l ane str i pin g on the side across from the T-in tersec ti o n sho uld be disco ntin - ued only at the crosswa lk s. (See Fi g ure 8). Bike Lanes and Turning Lanes Bi ke lanes so metimes co mpli ca te bi cycle and motor vehicle tu rnin g movements at in tersections . Because they e ncourage bicyclists to keep Design Bike Lanes 26 guide for the development of bicycle facilities "'O ~ ·-:9 "= B£-Bl:I e n -£1:1 Q. 0) .s ~ (lJ Q. f!! Cl> i c: .~ 150 mm (6 in) ... (lJ so lid line .~ -~ -(lJ 0 ·-~ ..... Dotted line for bus stops l immediately beyond the intersection is optional ; otherw ise use 150 mm (6 in) solid line R3-1 7 R7 series sign (as appropriate) I 15-60 m (50-200 ft) dotted line if bus stop or heavy right-turn volume , otherwise solid line 150 mm (6 in) solid line Optional 100 mm (4 in) solid line R3-17 R7 series sign (as appropriate) 15-60 m (50-200 ft) dotted line - 0.6 m (2 ft) dot , 1.8 m (6 ft) space Figure 7. Typical pavement markings for bike lane on two-way street Design Bike Lanes "'O ~ ... ·-E Cl> Q. Ol .5 ~ (lJ Q. f!! Cl> i c: .~ ... (lJ .~ -~ -.~ ~ ..... guide for the development of bicycle facilities 27 Bus Stop - -- - - - - --~ - Bus Stop Bus Stop T-in te rsecti on w it h pa inted c ro sswa lks an d bu s stops T-intersectio n w ith no painted crosswa lk s --D-~.---,- T-intersecti on wi th pai nted c ross wa lks an d no bu s stops Fi gure 8 . Ty pi ca l Bi ke La ne Stri p in g at T-inte rse ction s to t he r ig ht and m oto r ists to kee p to t he left, both ope rato rs are so m ew hat di sco urage d fro m m erg i ng in ad va nce of tu rn s. Thu s, some b i cycl i st s m ay beg in left tu rn s fro m th e ri g ht-side bike la ne and so m e m otor ists m ay beg in ri g ht t urn s fr o m th e left of th e b i ke l ane . Bo t h m a neuve rs are cont ra ry to es t ab li shed rul es of t he ro ad and m ay resu It i n c o nfli c ts; how- ever, t hese c an be lesse ned by sig ni ng and st ri ping . At i nte rsec t ion s, bicycl ist s p roceed i ng stra ig ht thro ug h and m o to ri st s t u rnin g r ig ht mu st c ross path s. Str i p in g and sig n in g co nfig urat io ns w hi c h encourage c ross in gs i n advance of th e inte rsec tion , in a m e rg i ng fas hi on , are prefe rab le to t hose t hat force t he c ross in g in t he immed iate v i c i n ity of t he in te rsec t io n . O ne exa mpl e of suc h a co nfi gurati o n i s g iv en in Figure 9. To a l esse r exte nt, th e sa m e i s tr ue fo r left-t urni ng b ic ycl ists; howeve r, in th is m a neuve r, m os t ve h ic le c od es a llow t he bi cycl ist t he o ptio n o f m ak i ng e ithe r a "ve h ic ul ar sty l e" left t urn (w he re t he b icycli st m erges leftward to t he sa m e la ne use d for m oto r ve hi cl e left t urn s) or a "ped es- tr ian sty le" left t urn (whe re t he bi cycli st proceed s strai ght thro ug h t he i nte rsec ti o n, turn s left at t he fa r sid e, th e n p ro cee d s ac ro ss th e inte rsec - ti o n agai n o n th e c ross str eet). (See Fi gure 10 .) Design Bike Lanes 28 guide for the development of bicycle facilities Figure 9 . Markings for Bik e Lane Merge in Advance of Intersection Design Bike Lanes I I t 0)!!8 I I Lime aue1 Bike t I I I I j I I I I I I I I I IT Ped . Crossi11 ~1 ----<• • I-""' 11 •. ~~~~-----"" ---1 I ~ - - -~3ffi "\ ------ 1 1 ~ -- -- - 1 ti ------I ~ -- --- -------I II / "'' ~~-------f: ~ -------1 I _D J Ped . Cross ing 1 tl 1 I ---Bik e Travel I r I Mot o1· Veh icle Tr av el -,_1 I <l )j !8 I 1 ~ an1 j Lane t Bike I I Figure 10. Typ ic al Bic ycle and Auto Movements at Major Intersectio ns Fi gure 11 prese nts o pti o na l trea tm e nts fo r pa veme nt mark in gs w here a b ike la ne approac hes a motori st ri g ht-tu rn -o nl y l ane (or lanes). Wh ere the re are num e ro us l eft-turn in g bi cycl ists , a se parat e tu rn i ng lane ca n a l so be con sid e red . Th e des ig n of b ike la nes shoul d a lso in clud e ap p ro- p ri ate signin g at inte rsec tion s to wa rn of co nfli cts. Ge nera l g uid ance fo r pave me nt markin g of bike lan es is co nta in ed in th e MU TCD 2 . Th e ap- p roac h sho uld e r w id t h sho ul d be p rov ided thro ugh t he in te rsec ti o n, w here fe asi bl e, to acco mmod ate rig ht -t urn in g bi cycl i sts o r bi cycl ists w ho prefe r to use c rosswa lk s to negot i ate th e in tersect ion . Inte rsec t io ns w ith throa t w id e nin g at app roac hes t hat prov ide an exc lu - sive l eft-turn bay ca n a lso p rovid e an exc lu sive ri g ht-turn lane fo r motor ve hicl es. In t hose cases w he re throat w id enin g has red uced t he ava i labl e pave m ent widt h be low th e minimum req uireme nts fo r b ike l a ne o pera - ti o n and it i s not poss ib le to w id e n t he pave me nt, th e bike l ane stripin g sho uld be di sco ntinu ed fo l lo w in g a regu latory sign . Bicycl i st s p roceed- i ng strai ght thr o ugh th e inte rsec ti o n sho uld be direc ted to me rge w ith m ot o r ve h icl e traffi c to cro ss th e in te rsect i o n. (See Fig ure 12 .) Wh ere suf- fic ient width ex ists , a se para te t hro ug h b i ke l ane sho ul d be p l ace d t o th e r ight of t he t h rou g h l ane as shown in Fig ure 11 . guide for the development of bicycle facilities 29 a. Right-turn-only lane .... IUlll 11'KT~LAU v1i:lf11m "''"""" MUST TIAINll~ R3-7R R4-4 at beginning of right-turn lane b. Parking lane Into right-turn-only lane NOTE: The dotted lines in cases "a" and "b" are optional (see case "c ''.) c. Right-turn-only lane t:MUJI[ .&. MUST llGlll 11'111'.ltLm Yl~TO tlm R3-7R A44 at beginning of right-tum lane d. Optional rig ht/straight and right-turn-only I Figure 11. Bike Lanes Approaching Ri ght-Turn-Only Lane s ... ... ""'""" MUST TURNRIGKT R3-7R BCG IN UK'l l Lm Y!EIJTOl!lU R4-4 at beginning of right-tum lane Design Bike Lanes 30 guide for the development of bicycle facilities RIGHT LANE MUST TURN RIGHT R3-7R BEGIN RIGHT TURN LANE It YIELD TO BIKES R4-4 Figure 12. Bike Lane Approaching an Intersection with Throat Widening Design Bike Lanes guide for the development of bicycle facilities 31 Bike Lane Symbol Guidelines A bike l ane should be painted with sta ndard pavem ent symbo l s to inform bicyclists and motorists of the presence of th e bike l ane. Th e sta ndard pavement symbols are one of two bicycle symbols (o r th e words "BIK E LA NE ") and a directio nal ar row. (See Figure 13.) These symbols should be painted on the far sid e of eac h intersect ion . (See Fi gure 14.) Addi- tional ste nc il s may be placed o n long, uninterrupted sectio ns of roadway. A ll pavement m arkin gs are to be w hi te and reflectorized. Th e Preferential Lane Symbol ("diamond ") previously used as a pave- ment mar kin g and on sig ns to show preferenti al us e by different classes of vehicles should no longer be used for bikeways, due to the co nfusion w ith the use of the diamond for Hi gh Occ u pant Vehicle (HOV) l anes , and t he misinterp reta ti o n of the diamond as a two-way arrow. These symbo ls should be elimi nated t hro ugh no rm al maintenance practices . -- I• I 1 lj 1 ' ... Directional arrow Preferred symbols D = 0.1 m x 0.1 m (4 in x 4 in) I - :W ...._ __ _ -•1•-• • • j I I Figure 13. Typical Bike Lane Symbols Word legend (optional) Design Bike Lane Symbol Guidelines 32 guide for the development of bicycle facilities 150 mm (6 in) I 1.8 m (6 ft) (optional) 1.8 m (6 ft) 1.8 m (6 ft) 1.8 m (6 ft) Notes: 1 . The bicycle rider symbol or the word pavement marking "BIKE LANE " may be used i nstead of the bicycle-only symbol. 2. See Figures 7 and 13 for additional information. Figure 14. Typical Bike Lane Marking on Far Side of Intersection Design Bike Lane Symbol Guidelines guide for the development of bicycle facilities 33 Shared Use Paths Shared use path s are faci l iti es o n ex clusive ri g ht-of-way and w it h mini- m a l cross flow by motor vehic les. Shared use paths are so m etimes refe rr ed to as trail s; however, in many states th e term tra il m eans an un- imp roved recreational faci li ty. Ca re should be taken in usin g these terms interchangea bl y. Where shared use paths are ca ll ed tra il s, they shou ld m eet a ll des ign crite ri a for shared use pat hs to be designated as bicycle faci l ities. Users are non-motorized and m ay include but are not limited to : bicyclists, in-line skaters , roll e r skaters, wheelchair use rs (both non -moto rized and motorized) and pedestrians, including wa lkers , run - ners, people with baby strollers, people walking dogs, etc. These facilities a re most co mmonl y designed for two-way travel, and the guid- ance herein ass um es a two-way faci li ty is pl ann ed unl ess otherw ise stated. Shared use path s can se rv e a var iety of purposes. They ca n provide users with a sho rtcut through a re sid entia l ne ig hborh ood (e.g., a connection between two cul-de-sac streets). Lo cated in a park, they ca n provide an enjoyable recr eatio na l opportun ity. Shared us e paths can be lo ca ted along rivers, ocean fronts, canals, aba ndon ed or active ra i l ro ad a nd uti l- ity rights-of-way, l im ited access freeways, within co llege campuses or within and between parks. Shared use path s ca n a lso provide bicycle ac- cess to a reas th at are othe rwi se se rv ed only by limited access hi g hways closed to b icycles. App ropri ate locations can be id e ntifi ed during t he p lanning process . Examp les of shared us e paths a re show n in Fi gu res 1 5 and 16. Sh ared use path s shou ld be thought of as a co mpl e mentary syste m of off-road t ransportatio n routes for b icyclists and others that serves as a necessary ex ten sio n to the ro adway netwo rk . Shared use paths shou ld not be use d to preclude o n-road bicycle faci liti es, but rath e r to supple- m ent a sys tem of o n-road bike la nes, wide o utsi de lan es, paved shoulders a nd bike routes. Th ere are so m e simil arities betwee n the de- sig n c riteria for shared use paths and hi g hways (e.g., ho ri zo ntal ali gn m ent, sight distance req uirements, sign in g a nd markin gs). On the other hand, some cr ite ria (e.g., horizonta l and vertical clearance requi re- m ents, gra des and pavement st ru cture) are dictated by operatin g characteristics of bicycles th at a re substanti a ll y different from those of motor ve hicles. The d es ig ne r should a l ways be aw are of th e similar iti es and differences between bicycl es and motor ve hicl es and of how these simil arit ies and differences influ ence the design of shared use paths. The remainder of thi s sect ion prov id es g uidance on eac h of th e factors that should be considered in desi g nin g safe and functional shared use pat hs. Separation Between Shared Use Paths and Roadways When two-way shared use p at hs are located immed iate ly ad j ace nt to a ro adway, so m e operat ion al problems are likely to occu r . In some cases, paths a lo ng hi g hways for short sect ions are pe rmi ss ibl e, g iven an ap pro- priate leve l of sepa rat ion betwee n facilities, as in Fig ure 16. Some Figure 15. Example of a Shared Use Path Figure 16. Example of a Shared Use Path Design Shared Use Paths 34 guide for the development of bicycle facilities rt: ( I:(\\ U' Design Shared Use Paths prob lem s w it h paths located immed iate ly ad j acent to roadways are as fol lows: 1. Un less separated, they require one d irection of bicycle traffic to r ide aga in st motor ve hi cle traffic, co ntrary to normal rules of t he road. 2. When the path ends, bicyclists go ing against traffic will tend to co ntinu e to travel on th e wrong side of th e street. Likewise , b icy- cl i sts app roac hin g a shared use path often travel o n th e wrong sid e of the street in ge ttin g to the pa th . Wron g-way travel by b i- cycl ists i s a major ca use of bicycle/automobile cras hes and shou ld be discouraged at every opportuni ty. 3. At inters ectio ns, motori sts enter in g o r crossing the ro adway of- te n will not noti ce b icyclists app roa c hi ng from their right, as they are not expect in g contra-flow vehicles. Moto rists turnin g to exit the roadway may l ikewise fai l to no t ice the b icycl i st. Even b icyclists com in g from the left ofte n go unnoticed, espec i al ly when sig ht distances are limi ted. 4. Sig ns posted for ro adway users are backwards for contra-flow bike traffic; therefo re these cyclists are un able to read the infor- mation without stopp in g and turni ng around. 5 . When t he avai lab le ri g ht-of-way is too narrow to acco mmod ate a ll hi g hway and sha red use path fea tures , it may be prudent to conside r a reduction of the existing or proposed widths of t he various highway (a nd bikeway) cross-sectiona l e le ments (i.e., l ane and sho uld er widths, etc.). However, any reduction to less than AASHTO Green Book 1 (or othe r applicable) design c rite ri a must be supported by a documented engineering ana lysis . 6. Many bicyclists wi ll use the roadway instead of the shared use pat h because they have found t he road way to be more co nve- ni e nt, better maintained, or safer. Bicycli sts using the ro adway may be harassed by so me motorists who fee l that in a ll cases bi- cyclists shou ld be o n th e adjacent path. 7. A lthough the sha red use path shou ld be g ive n the same priority thro ugh intersections as the para ll e l hi ghway, moto ri sts fa lse l y expec t bicyclists to stop or yie ld at a l I cross-stree ts and drive- ways . Efforts to require or encourage bi cyclists to y ie l d or stop at each cross-street and driveway are inappropriate a nd frequently ignored by bicyclists. 8. 9. Stopped cross-stree t motor ve h icle traffic or veh icl es ex itin g sid e st reets or driveways ma y b l oc k the path crossing. Because of the proximity of motor vehicle t raffic to opposing bi- cycl e traffic, bar ri ers are often necessary to keep motor vehic les o ut of shared use paths and bicycl ists out of traffic lanes . These barriers can represent a n obstruct ion to bicyclists and moto ri sts, guide for the development of bicycle facilities 35 ca n complicate maintena nce of the facility , and ca n cause other problems as well. For the above reasons, other types of bikeways are I ike ly to be better suited to accommodate bi cycle tr affic alo ng hi g hway co rridors, depend- in g up on traffic cond itions. Shared use paths shoul d not be conside red a substitute for street improvements even when the path is located ad j a- ce nt to the hi g hway, because many bi cyclists will find it less conve ni e nt to rid e o n the se pat hs co mpared with the st reets, part icul arl y for utility trip s. When two-w ay sha red us e pat hs are locate d ad j ace nt to a roadway, wide sepa ration betwee n a sha red us e path and the ad j ace nt highway is des irable to d emonstrate to both the bicyclist and the motori st that th e path funct ions as an ind epend e nt fac ility for bicyclists and others. When thi s is not pos sibl e and the dista nce betwee n the edge of th e sho ulder and the shared use path is less than 1 .5 m (5 feet), a suita bl e physical bar- ri er i s recommended. Such barriers serve both to prevent path users from m akin g unwanted move ments between the path and t he hi ghway shoul- d er and to re inforce the co ncept th at the path is an independent fac ility. Where used, the barrier should be a minimum of 1 .1 m (42 in ches) hi gh, to prevent bicyclists from toppling over it. A barrier between a share d us e p ath and adjacent highway should not impair sig ht distance at intersec- tions, and should be designed to not be a haz a rd to er rant m oto ri sts. Width and Clearance Th e paved width and the operating width required for a shared use path are primary d es ign consid erat io ns. Fi gure 1 7 depicts a shared use path on a sepa rated right of way. Under most co nditi ons, a recom m end ed paved width for a two-directiona l shared use path is 3.0 m (10 fee t ). In .._ 0.9 m (3 tt ) min . ~ 1 .8 m (6 tt ) max. i . 5 ~ EE E'E' .._ 0 .9 m (3 tt) min . ~ ....___~__, i 1.8 m (6 tt) max . .5 ~ EE E'E' ~~ EE ~~ Figure 17. Cross Section of Two-Way Shared Use Path on Separated Right-of-Way Design Shared Use Paths 36 guide for the development of bicycle facilities Figure 18. Safety Rail Between Shared Use Path and Adjacent Slope and Waterway Design Shared Use Paths rare in stances, a reduced width of 2.4 m (8 feet) can be adequate . This re- duced width shou ld be used only where the fo ll owing co nditi o ns preva il: (1) bicycle traffic is expected to be low, even on peak days o r during peak hours, (2) pedestrian use of the facility is not expected to be more than occasional , (3) there wi ll be good hori zontal and vertical a li g nme nt providing safe and frequ ent pass in g opportunities, and (4) dur- ing normal maintenance ac tiviti es the path will not be subjected to maintenance vehicle load in g conditions that would cause pavement edge damage. Under certain co nditi ons it may be necessary or desirable to increase the width of a shared use path to 3.6 m (1 2 feet), or even 4.2 m (14 feet), due to substant ia l us e by bicycles, j oggers, skate rs a nd pe- dest ri ans, use by large maintenance vehicles, and/or steep grades. T he minimum width of a one-directional shared use path is 1 .8 m (6 feet). It shou ld be recognized, however, that one-way paths ofte n will be used as two-way faci liti es unless effect ive measures are take n to assure one-way operation. Without suc h enforce m e nt, it should be assumed that shared use paths wi ll be used as two -way facilities by both pedestri- ans and bicyclists and designed according ly. A minimum 0.6-m (2-foot) wide graded area with a maximum 1 :6 slope sho uld be maintained ad j ace nt to both sides of the path ; however, 0.9 m (3 feet) or more is desirable to provide cleara nce from trees , poles, walls, fences, guardrai l s or other late ral obstructio ns. Where the path is adja- cent to ca nal s, ditches or slopes down steeper than 1 :3 , a wider separat io n should be co nsid e red . A minimum 1 .5 m (5-foot) separation from the edge of the path pavement to the top of the slope is desirable. Depending on the height of embankment and condition at the bottom , a physical barrier, such as dense shrubbery, railin g or chain link fence, may need to be provided. (See Figure 18.) T he vert ica l clearance to obstructions shou ld be a minimum of 2.5 m (8 feet). H owever, vertical clearance may need to be g reater to permit pas- sage of maintenance and e m ergency veh icl es. In undercrossings and tunnels , 3.0 m (10 feet) is desirable for adeq uate vertical shy distance. Design Speed The speed a bicyclist travels is depende nt on several factors, includin g the type and co nditi on of the bicycle; the purpose of the trip; the co ndi- tion, locati on and grade of the path ; the speed and direction of any prevailing winds; the number and types of user s on the path; a nd the physical co nd iti on of the bicyclist. Shared use paths shou ld be designed for a se lected speed that is at least as high as th e preferred speed of the faster bicyclists . In ge ne ra l , a minimum design speed of 30 km/h (20 mph) shou Id be used. Although bicyclists can trave l faster than th is, to do so would be inappropriate in a mi xed-use sett in g. Design and tr affic con- trols can be used to deter excess ive speed and faster cycl ists ca n be enco uraged to use the roadway system. Lower design speeds should not be se l ected to art ifi cia ll y lowe r us er speeds. When a downgrade exceeds 4 percent, or w here strong prevailing tailwinds ex ist, a design speed of 50 km /h (30 mph) or more is advisable . guide for development of bicycle facilities 37 On unpaved paths, where bicyclists tend to rid e more slowly, a lower design spee d of 25 km /h (15 mph ) can be u sed. Simil a rl y, whe re th e g rades o r the prevailing winds dictate, a hi g he r design speed of 40 km/h (25 mph) ca n be used. Sin ce bicycles have a hi gher te nd ency to sk id on unpaved surfaces , hor izontal c urvature design shou ld take into acco unt lower coe ffici ents of fri cti on. Horizontal Alignment Unlike an automobile, a bi cycle must be lea ned whi le corner in g to pre- vent it from falling outward due to the ge ne rat ion of ce ntrifuga l force. The balance of ce ntrifu ga l fo rce due to co rn ering, a nd the bicycle's downward force due to its weig ht, ac t through the bicycle/operator co m - bined ce nter of mass and mu st inte rs ect a lin e that con nects the fro nt and rea r tire co nta ct points. If bicyclists pedal throug h sha rp turn s and lea n too far, th e peda l wi 11 strike the g round because of a sha rp lea n ang le. A ltho ugh pedal he ig hts are different for different m akes of bikes, t he pedal ge nerall y wi ll st rik e th e grou nd wh en the lea n ang le reac hes about 25 °. However, casua l bi- cyclists usuall y do not like to lea n too drast ica lly, and 15-20° is considered th e maximum lean ang le. Assuming an o perator who sits stra ight in th e seat, a simple eq uation ca n determine the minimum radius of c urvat ure for any g iven lean ang le: For Metric Units: R = 0.0079 V 2 tan e Where: R =Min imu m radius o f cu rv ature (m ) V = Des ign Speed (k m/h) e = Lea n angle from th e vert ica l (deg rees ) Fo r Eng li sh Units: R = 0.067 V 2 tan e Wh e re : R =M i nimum radi us of curvature (ft) V = Des ign Speed (mph ) e = Lean angle from th e vert ica l (degrees) However, when t he lea n ang l e ap proac hes 20°, the minimum radius of curvature negotiab le by a bicycle becomes a fun ct ion of th e superelevation rate of the pathway surface , the coeffic ie nt of friction be- tween the bi cycle tires and the surface, a nd th e speed of the bicycle. For thi s sit uat io n, th e minimum des ig n radiu s of c urvature ca n be derived from the fo ll owing formu l a: Fo r Metric U ni ts: R Where: y 2 127(~+ f) 100 R =Mi nimum radius of cu rv ature (m) V = Des ign Speed (k m/h) e = Rate of bikeway supe re levation (percent) = Coe ffi c ient of fr ictio n For English Units: y 2 R 1 s(~+f) 100 Where : R =Minimum radius of curvature (ft) V = Desi gn Speed (m p h) e = Rate of bikeway supere leva tion (percent) =Coefficient of friction Design Shared Use Paths 38 guide for the development of bicycle facilities Design Shared Use Paths Since most shared use paths built in the U nited Sta tes mu st a l so m ee t th e requirements of the America ns w ith Disabi liti es Act (ADA), ADA guide- lines require that cross sl opes not exceed 2-3 perce nt to avo id the severe difficulties that greater cross slopes can c rea te for peop le usin g whee l- chairs. Thus , for most share d use paths , t he m ax imum superelevation rate w ill be 3 percent. Whe n t ransitioning a 3 perce nt supere levation , a minimum 7.5-m (25-foot) transition distance sho uld be prov id ed be- twee n the e nd and begin nin g of consec utive and reversing ho ri zo nta l curves . The coefficie nt of friction depe nd s upon spee d ; su rface type, ro ug hn ess, and co ndition ; tire type and co nditi on ; and w heth e r t he su rfa ce is wet o r dry. Fri ct io n factors used fo r d es ig n sho uld be se lect ed based up o n th e poi nt at w hi c h centrifuga l fo rce ca uses t he bi c ycli st to recog ni ze a fee l- ing of d isco m fort and in stin ctive ly act to avo id hi g he r speed. Extrapolating fro m va lu es use d in hi ghway d es ig n, d es ign fri ction factors for paved sha red use paths ca n be assumed to v ary from 0.3 1 at 20 km /h (12 mph ) to 0.21 at 50 km /h (3 0 mph ). A lthough th ere are no data ava il- ab le fo r unpaved surfaces, it i s suggested th at friction facto rs be reduced by 50 pe rce nt to a ll ow a suffic ie nt margin of sa fety . Based up on va r ious design speeds of 20-50 km /h (12 -30 mph) and a de- sirab le max imum lea n a ng le of 1 5°, minim um rad i i of curvature for a paved path can be selec ted from Tab le 1. Table 1. Desirable Minimum Radii for Paved Shared Use Paths Based on 15 ° Le a n Angle Design Speed (V) Minimum Radius (R) km/h (mph) m (ft) .---~......,,..20,,-(1 2 _1~2 ..... _____ _.....__~ 30 (20) 27 40 (25) 4 7 50 (3m 74 Where a grea ter lea n ang le ca n be to lerate d , the minimum rad ii of curva- ture for a 2 pe rcent supe re leva tion rate and variou s d es ig n speeds of 20-50 km /h (1 2-30 mph) ca n be t ake n from T ab le 2. Table 2. Minimum Radii for Paved Shared Use Paths Based on 2 % Superelevation Rates and 20 ° Lean Angle Design Speed (V) km/h (mph ) Friction Factor (f) (paved surface) Minimum Radius (R) m (ft) ------~ 2 0 __ _,,,1..,2"-0.31 10 30 30 (20 ) 0.28 _______ 2_4 ___ __..(9_0_)_ 40 (25) 0.25 47 (155) 50 (30) 0.21 86 (260 ) guide for development of bicycle facilities 39 However, when a lea n angle of 20° is used , more horizontal space will be taken up by the bicycl ist taking the curve and more width needs to be provided. In these cases the pathway width should be in creased and a center line placed down the middle of t he path. When curve radii sma ll er than those shown in Table 2 must be used be- cause of limited right-of-way, topographical feat ures or other considerations , standard c urve wa rnin g signs and supp lemental pave- ment markings shou ld be in sta ll ed in accorda nce with the MUTC0 2 • The ne gat ive effects of sharper curves can al so be partially offset by w id - ening the pavement through the curves. Grade Grades on shared use paths shou ld be kept to a minimum, especially on lon g inclines . Grades greater than 5 percent are und es irab le because th e ascents are difficult for many bicyclists to climb and the desc ents cause some bicyclists to exceed the speeds at which they are compete nt or comfortab le. On some shared use paths , whe re terrain dictates, des ign- ers may need to exceed the 5 percent grade recom mended for bicycles for some sho rt sections. As a genera l guide, the followi ng grade restric- tions and grade lengt hs are suggested:* 5-6% 7% 8% 9% 10% 11+% for up to 240 m (800 ft) for up to 120 m (400 ft) for up to 90 m (300 ft) for up to 60 m (200 ft) for up to 30 m (100 ft) for up to 15 m (50 ft) Grades steeper than 3 percent may not be practical for shared use paths with crushed stone or other unpaved surfaces for both handling and drainage eros ion reasons. Options to miti gate excessive grades: 0 When using a lo nger grade, an additi o nal 1 .2 -1 .8 m (4-6 feet) of width to permit slower speed bicyclists to dismount and walk may be cons id ered . .) Provide signin g that alerts bicyclists to the maximum percent of grade (MUTC0 2 ). ~) Provide recommended descent speed sig nin g. J Excee d minimum stopp in g sight distances. 0 Exce ed minimum horizontal clearances , recovery area and /or pro- tective bike rai l s. *See Chapter 2-0ther D es ign Considerations, Accessibi l ity Requirements, p. 69. Design Shared Use Paths 40 guide for the development of bicycle facilities Design Shared Use Paths ) When possible, use a w ider path [1.2-1 .8 m (4-6 feet) addition rec- ommended] and a ser ies of short switc h bac ks to conta i n the speed of descending b icyclists. Sight Distance To provide bicyclists w ith an opportunity to see and react to the unex- pected, a sha red use path shou ld be designed with adequate stopping sig ht d i sta nces. The d i st ance required to b rin g a bicycle to a fu ll con- tro ll ed stop is a function of the bicyclist's pe rception and brake reaction time, t he i ni t i a l speed of the b icycle, t he coeff ic ie nt of friction between the t i res and the pavement, a nd the braking ab il ity of the b i cycle. Figu re 19 in d icates the min im um stopping sight distance for various de- sign speeds and grades based on a total perception and brake reaction time of 2.5 seco nds and a coefficient of frict io n of 0 .25 to acco u nt for the poo r wet weather brak i ng characteristics of many bicycles. For two-way shared use paths , the sight d istance in the desce nding direction, that is, w he re "G " is negative, wi ll co ntrol the des ig n . Tab le 3 is used to se l ect t he mi nimum lengt h of vertical curve necessary to prov ide min i mum stoppi ng sight d istance at various speeds on crest ve rtica l curves. The eye he ig ht of the bicycl ist is assumed to be 1400 mm (4 1/2 feet) and the obj ect he ig ht is assumed to be 0 mm (0 i nc hes) to rec- ognize that impediments to b icycle trave l exist at pavement level. Tab le 4 indicates the m i nim u m clearance t hat shou ld be used for line of sight obs t r uct io ns for horizo nta l curves. The latera l clea rance is obta i ned by enter i ng Table 4 w ith the stopping sight di stance from Figure 19 and the proposed horizonta l rad i us of curvatu re. Bicyclists frequently ride side-by-side on shared use paths , and on narrow pat hs bicycl ists have a tende ncy to ri de nea r t he midd le of the path. For these reasons , and because of the hi gher pote nt ial for bicycle crashes, lat- era l clearances on horizonta l c urves shou ld be ca lcu lated based on the sum of t he stopp in g sight distances for bicyclists trave l ing in oppos ite directions around the curve. Where this is not poss i b le or feasible, consideration shou ld be give n to wideni ng t he path throug h th e c urve , insta llin g a yellow center l i ne stripe, installing a "Curve Ahead" warn i ng sign i n accordance w ith the MUTCD 2 , or some combination of t hese alternatives. guide for the development of bicycle facilities 41 250 200 E I 150 Ql (.) c ro iii 'O -..c Cl 100 ·u; Cl c tTo: - imVb \ \ \ I \ \ . \ \ ~!UK .:.u I Nll. i l l \ \\ \ \ \\ \ ' . -"' . ' "' I\ -' \ .. 4) kn /h ' intn \\ ' L\ .... \ \\ \ \ \\ \ \ \ \ \ \ \ \ ·' \ . \ , • ... ~ . ' "\ \ \ \ \ " \ _, i • \ -\ ·a. c.. 0 U5 50 -.. ,. "" r -\ ~ . --. - I - 0 0 s v 2 v +- 254 (f ± G ) 1 .4 Wh ere: S v f G ' ~ . \. ' --"\ . -\ \ , • .ti . . ' -I ..... ".' .. . .. .. . . I 5 10 Grade(%) stoppin g sig ht distance (m ) ve l ocity (km /h) coeffi c ie nt of friction (use 0 .25) g rad e (m/m ) (rise/run ) Figure 19. Metric Units. .. .. Minimum Stopping Sight Distance vs. Grades for Various Design Speeds :a-" " < U I ,\. \\ \ \ 0 \ 'la ,.- \ ~ .. ~ . ... . \ ~ \ ... \ 1" ' I ' \ . , .. , . .. .. ' - ., --- 15 Desce nd Asce nd , fr ~ • • . ,, • • ,, • " .. I .. ~I .... 20 ------ Design Shared Use Paths 42 guide for the development of bicycle facilities Design = ' Cl> u c 111 -rn c -.s:. en c;; en c a. a. 0 -en Descend Ascend Shared Use Paths 800.00 700.00 600.00 500.00 400.00 -., 300.00 200.00 100.00 0 ·- • " \1 \ 5 . • , \ \ . . " " " \ ' I '\ \ ' \ • I \ - ' \ 'l ... '• - \ .. \ . -- 10 Grade(%) - \ " ' ... \ - \ ' \ \ " .. ... \ - \ \ 15 s v 2 ----+3 .67 V 30 (f ± G) W here: S v f G stop pin g sigh t dista nce (ft) ve loci ty (mph ) coe ffic i ent of fr ictio n (use 0.25) grade (ft/ft) (r ise/run) Figure 19. English Units. Minimum Stopping Sight Distance vs. Grades for Variou s Design Speeds. . -.. ,,. . ,. . - • 20 guide for development of bicycle facilities 43 Table 3. Metric Units. Minimum Len th of Crest Vertical Curve (L) Based on Sto A (%) 2 3 4 5 6 7 8 9 S = Stopping Sig ht Distance (m) 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 1 0 20 30 40 50 60 7 1 7 27 37 4 7 57 67 77 87 97 107 10 20 30 40 50 60 70 80 91 103 116 129 143 4 14 24 34 44 54 64 75 88 100 114 129 145 161 179 3 1 3 23 33 43 54 65 77 91 105 121 137 155 174 193 214 10 20 30 40 51 63 76 90 106 123 141 160 181 203 226 250 5 15 25 35 46 58 71 86 103 121 140 161 183 206 231 258 286 9 19 29 39 51 65 80 97 116 136 158 181 206 232 260 290 321 10 2 12 22 32 44 57 72 89 108 129 151 175 201 229 258 289 322 357 11 5 15 25 35 48 63 80 98 119 141 166 193 221 251 284 318 355 393 12 7 17 27 39 53 69 87 107 130 154 181 210 241 274 310 347 387 429 13 8 18 29 42 57 74 94 116 140 167 196 228 261 297 335 376 419 464 14 10 20 31 45 61 80 101 125 151 180 211 245 281 320 361 405 451 500 15 11 21 33 48 66 86 108 134 162 193 226 263 301 343 387 434 483 536 16 3 13 23 36 51 70 91 1 16 143 173 206 241 280 321 366 413 463 516 571 1 7 4 14 24 38 55 74 97 123 152 184 219 257 298 342 389 439 492 548 607 18 4 14 26 40 58 79 103 130 161 194 231 272 315 362 411 464 521 580 643 19 5 15 27 42 61 83 109 137 170 205 244 287 333 382 434 490 550 612 679 20 6 16 29 45 64 88 114 145 179 216 257 302 350 402 457 516 579 645 714 21 7 17 30 47 68 92 120 152 188 227 270 317 368 422 480 542 608 677 750 22 7 18 31 49 71 96 126 159 196 238 283 281 385 442 503 568 636 709 786 23 8 18 33 51 74 101 131 166 205 248 296 347 403 462 526 593 665 741 821 24 8 19 34 54 77 105 137 174 214 259 309 362 420 482 549 619 694 774 857 25 9 20 36 56 80 109 143 181 223 270 321 377 438 502 571 645 723 806 893 whe n S > L w hen S < L L=25 -280 A AS 2 L=-- 280 H eight of cyc l ist eye -1400 mm H eight of object -0 m m Shaded area represe nts S = L L =Mi nimu m Length of Vert ica l Curve (m) A = A lge braic Grade D ifference (%) S =Stopping Sig ht Distanc e (m) M inimum Length of Vert ical C urve = 1 m Design Shared Use Paths 44 guide for the development of bicycle facilities T bl 3 E I' h U 't M' . a e ng1s ni s. m1mum L th f C t V f IC eng 0 res er 1ca urve (L) B d St ase on s· ht D' t ooomg 1g1 1s ance A S = Stopping Sight Di stance (ft) (%) 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 2 30 70 110 150 3 20 60 10 0 140 180 220 260 300 4 15 55 95 135 175 2 15 256 300 348 400 5 20 60 10 0 14 0 180 222 269 320 376 436 500 6 10 50 90 13 0 171 216 267 323 384 451 52 3 600 7 31 71 111 152 199 252 311 3 76 448 526 610 700 8 8 48 88 128 174 228 288 356 430 512 601 697 800 9 20 60 100 144 196 256 324 400 484 576 676 784 900 10 30 70 111 160 218 284 360 444 538 640 751 871 1000 11 38 78 122 176 240 313 396 489 592 704 826 958 1100 12 5 45 85 133 192 261 341 432 533 645 768 901 1045 1200 13 11 5 1 92 144 208 283 370 468 578 699 832 976 1132 1300 14 16 56 100 156 224 305 398 504 622 753 896 1052 1220 1400 15 20 60 107 167 240 327 427 540 667 807 960 112 7 1307 1500 16 24 64 114 178 256 348 455 576 711 860 1024 1202 1394 1600 17 27 68 121 189 272 370 484 612 756 914 1088 12 77 1481 1700 18 30 72 128 200 288 392 512 648 800 968 11 52 1352 1568 1800 19 33 76 135 2 11 304 414 540 684 844 1022 1216 1427 1655 1900 20 35 80 14 2 222 320 436 569 720 889 1076 1280 1502 1742 2000 21 37 84 149 233 336 457 597 756 933 1129 1344 1577 1829 2100 22 39 88 156 244 352 479 626 792 978 1183 1408 1652 1916 2200 23 41 92 164 256 368 501 654 828 1022 1237 1472 1728 2004 2300 24 3 43 96 171 267 384 523 683 864 1067 1291 1536 1803 2091 2400 25 4 I 44 100 177 278 400 544 711 900 1111 1344 1600 1878 2178 2500 wh en S > L L = 25 -900 Sh aded area repr ese nts S = L A L =Minimum Length of Ve rti ca l Curve (ft) when S < L L= AS ' A =Algebrai c Grad e Differen ce (%) 900 S =Stopping Si g ht Distance (ft ) H e ig ht of cyclist's eye -4 1/2 ft Minimum Le ngth of Ve rti c a l C u rve = 3 ft. Hei g ht of obj ect -0 ft Design Shared Use Paths guide for the development of bicycle facilities 45 Table 4. Metric Units. Minimum Lateral Clearance (M) for Horizontal Curves Stoppi ng Sight distance (S) measu red along this line S = Stopping Sight Dista nce (m) R = Rad ius of centerline of lane (m) M = Distance from cente rline of la ne to obstructi on (m) Angle is expressed in deg rees M = R ~ -co~2B .~5S) J R [ -1 ( R-M )] 5 = 26.65 Los -R- Formula app lies only when S is equal to or less than length of curve . Line of sight is 700 mm above centerl ine of inside lane at point of obstruction . For Metric U nits: S =Stoppin g Sight Dis tance (m) R =Rad iu s of center lin e of lane (m) M =Dista nce from ce nterlin e of lane to o bst ru ctio n (m) For En g li sh U ni ts: S =Stopp in g Sight D is tance (ft) R = Rad i us of ce nterl ine of lane (ft) M = Di stance from ce nte rlin e of lane to o bstru cti o n (ft) R (m) S = Stopping Sight Distance (m) 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 10 1 .2 2.7 4 .6 6.8 9.3 15 0.8 1 .8 3.2 4.9 6 .9 9.1 11 14 20 0.6 1.4 2 .4 3.8 5.4 7.2 9.2 11 14 16 19 25 0 .5 1.1 2 3.1 4 .4 5.9 7.6 9.5 11 14 16 18 2 1 23 50 0.3 0 .6 1.6 2.2 3 3.9 5 6.1 7.4 8.7 10 12 13 15 1 7 19 2 1 23 1 .5 2 2.7 3.4 4.1 5 5.9 6 .9 8 9.2 10 12 13 15 16 75 0.2 0 .4 0.7 100 0 .1 0 .3 0 .5 0 .8 1 .1 1 .5 2 2.5 3.1 3 .8 4 .5 5 .2 6 .1 7 7.9 8.9 10 11 12 125 0.1 0 .2 0 .4 0.6 0 .9 1 .2 1 .6 2 2.5 3 3.6 4 .2 4 .9 5.6 6 .3 7.2 8 8.9 9.9 150 0.2 0.3 0.5 0.7 1 .3 1 .7 2.1 2 .5 3 3.5 4.1 4.7 5 .3 6 6 .7 7.5 8.3 175 0.2 0 .3 0.4 0 .6 0 .9 1 .1 1 .4 1 .8 2.2 2.6 3 3.5 4 4 .6 5.1 5.8 6.4 7.1 200 0. 1 0 .3 0.4 0 .6 0 .8 1 .3 1 .6 1 .9 2.2 2 .6 3.1 3.5 4 4.5 5 5.6 6.2 225 0.1 0 .2 0.3 0.5 0.7 0.9 1 .1 1.4 1 .7 2 2.3 2 .7 3.1 3.5 4 4.5 5 5.5 250 0 . 1 0.2 0.3 0.5 0 .6 0 .8 1 .2 1.5 1.8 2.1 2.4 2.8 3 .2 3.6 4 4.5 5 275 0.1 0.2 0.3 0.4 0 .6 0.7 0 .9 1 .1 1 .4 1 .6 1 .9 2.2 2.6 2.9 3.3 3.7 4 .1 4.5 300 0.2 0.3 0 .4 0 .5 0.7 0.8 1 .3 1 .5 1 .8 2 2.3 2.7 3 3.4 3.8 4 .2 Design Shared Use Paths 46 guide for the development of bicycle facilities Design Shared Use Paths R (ft) S = Stopping Sight Distance (ft) 20 40 60 80 100 120 140 160 180 2 00 220 240 260 280 300 25 2.0 7.6 15.9 5 0 1.0 3.9 8.7 15.2 23 .0 3 1 .9 4 1 .5 75 0.7 2.7 5.9 10.4 16.1 22.8 30.4 38.8 47.8 57.4 67.2 95 0.5 2.1 4.7 8.3 12.9 18.3 24.7 3 1 .8 39.5 48.0 56.9 66.3 75 .9 85.8 125 0.4 1 .6 3.6 6.3 9 .9 14.1 19.1 24 .7 31.0 37.9 45.4 53.3 61.7 70 .6 79.7 155 0.3 1 .3 2.9 5.1 8.0 11 .5 15 .5 20.2 25.4 31 .2 37.4 44.2 5 1.4 59.1 67.1 175 0 .3 1.1 2.6 4.6 7.1 10.2 13.8 18.0 22.6 27.8 33.5 39.6 46 .1 53.1 60.5 200 0.3 1 .0 2.2 4.0 6.2 8.9 12.1 15.8 19 .9 24.5 29 .5 34.9 40.8 47.0 53.7 225 0.2 0 .9 2.0 3 .5 5.5 8.0 10.8 14.1 17 .8 21.9 26.4 31.3 36.5 42.2 48.2 250 0 .2 0 .8 1 .8 3.2 5.0 7.2 9.7 12.7 16 .0 19.7 23.8 28.3 33.1 38.2 43.7 275 0.2 0.7 1.6 2.9 4.5 6 .5 8.9 11.6 14.6 18.0 2 1 .7 25.8 30.2 34.9 39.9 300 0 .2 0.7 1.5 2 .7 4.2 6.0 8.1 10.6 13.4 16.5 19.9 23.7 27.7 32.1 36.7 350 0.1 0.6 1 .3 2.3 3.6 5.1 7.0 9 .1 11 .5 14 .2 1 7.1 20.4 23.9 27.6 3 1 .7 390 0.1 0.5 1 .2 2.1 3.2 4.6 6.3 8.2 10.3 12.8 15.4 18.3 21.5 24.9 28.5 500 0.1 0.4 0.9 1 .6 2 .5 3 .6 4.9 6.4 8.1 10.0 12.1 14 .3 16.8 19.5 22 .3 565 0.4 0.8 1.4 2.2 3 .2 4.3 5.7 7.2 8 .8 10.7 12.7 14 .9 1 7.3 19.8 600 0.3 0.8 1.3 2.1 3.0 4.1 5.3 6.7 8 .3 10 .1 12.0 14.0 16 .3 18.7 700 0.3 0.6 1.1 1.8 2.6 3.5 4.6 5.8 7.1 8 .6 10.3 12.0 14.0 16.0 800 0.3 0.6 1.0 1.6 2.2 3.1 4.0 5.1 6 .2 7.6 9 .0 10.5 12.2 14.0 900 0.2 0 .5 0.9 1 .4 2.0 2.7 3 .6 4.5 5.6 6.7 8.0 9.4 10.9 12.5 1000 0.2 0.5 0.8 1 .3 1.8 2.4 3.2 4.0 5.0 6.0 7.2 8.4 9.8 11 .2 Table 4. English Units. Minimum Lateral Clearance (M) for Horizontal Curves Path-Roadway Intersections Intersect io ns between pat hs and roadways are often the most c riti ca l is- sue in shared use pat h desig n. Due to t he potent ial co nfli ct s at these junctions, ca reful design is of paramo u nt importance to the safety of path use rs and motor ists alike. Th e sol uti o ns provid ed in this c hap ter sho uld be co nsidered gui de l ines, not absolutes. Each intersection i s un iq ue and wi ll require sound engineer in g judgment on the part of the designer as to t he app rop ri ate so lution. There are three bas ic categories of path -roadway intersections: midb loc k, ad j ace nt pat h and complex. Th e fol lowing d isc uss ion pro- v ides guid ance fo r eac h of th ese catego ri es. Each of these in tersection types may cross any number of roadway lanes, divided or undi vided, w ith varyi ng speeds and vo lum es of motor vehicle traffic , and may be un con troll ed, or more ty pi ca ll y, sign or signal co nt ro l led. On l y at-grade c rossi ngs are addressed in th is section. guide for the development of bicycle facilities 47 Midblock Crossings Mi d bl ock type c rossi ngs are th e m os t st ra ig htfo rward o f th e three co nfi g- urat ions . Fi g ure 20 shows an exa mpl e of a midbl ock c ross in g. M idb l oc k c rossi n gs should be fa r e nou g h away fro m ex i sting i nte rsec ti o n s b etween roadways to be clea rl y se p arate fro m th e ac ti v ity th at occ urs as m oto ri st s app roach th ese in te rsect io n s (s u c h as m e rg in g m ove m e nts, acce l eration/ d ece l erat io n o r p rep aration s to ente r turn l anes). Th e re are m a ny o th er var i abl es to co nside r w hen d esig nin g t h is ty p e of in te rsec ti o n , in cl udin g ri ght of way ass ignm ent , t raffi c co ntro l d ev ices , sig ht distan ce fo r both bi- cycli sts and m otor ve hicl e ope rato rs, refu ge i sl and use, access control , and pave m e nt m ark in g. Th ese i ss u es are di sc u ssed in more d etai l l ate r in thi s sectio n . -------Varies -see MUTCD Section 98 ~~ ------- ---30 m (100 ft) --- I ~ Roadway 15 m Intersection traffic control devices as warranted 1 depending on conditions. + SeeMUTCD. 1.2 m (4 ft) + 1.5 m (5 ft) + 1.2 m (4 ft) :t <$> W2-1 Figure 20. Midblock Type Path Crossing Anoth er i mportant co n sid e rati o n for midbl oc k c ross in gs i s th e trea tm e nt fo r a skewed cross in g. Fi gure 2 1 d ep icts a p ath rea li gnme nt to achieve a 90-d eg ree c ro ss in g . A minimum 4 5-d eg ree c ro ssin g an g le m ay be ac- ce ptabl e to minimi ze r ig ht-of-way requirem e nts. Design Shared Use Paths 48 guide for the development of bicycle facilities Design Shared Use Paths , / , / , / Roadway , / , Figure 21. Typical Redesign of a Diagonal Road Crossing Adjacent Path Crossings Adjacent path crossings occur where a path crosses a roadway at an ex- isting intersect ion between two roadways, whether it is a T-inte rsection (including driveways ) or a si mple four-legged intersection (Figure 22 ). It is preferab le that this type of c ro ssing be carefull y integrated close to the intersection so as to allow motorists and path users alike to recognize each other as intersecting traffi c. With th is co nfi guration , the path user is faced with potential confl icts with motor ve hicl es turning left (A ) and right (B) from the paralle l roadway, and on the c ro ssed roadway (C, D , E). The major road may be eith er the parallel or crossed roadway. Right-of- way assignment, traffic co ntrol devi c es , and separation distance be- tween the roadway and pat h are also important variab les which greatly affect the design of this intersection. Further comp I icating the situation is the poss i bi l ity of the co nflicts being unexpected by both pat h users and motorists. Clear sight lines across corners are especially important. In a Type A turning movement (see Figure 22), it may be advisab le to pro- hibit permissive left turns on a high-vo lume par all el roadway and high- use path crossings. For turning movement Type B, as sma ll as pract i cal corner turning radius may be required to reduce the speeds of motor ve- hicles. For Type C and D movements, it may be advisab le to prohibit right-turns-on-red and p lace a stop bar in adva nce of the path crossing. To account for vehicle movement E, it may require an all-red phase to protect the path users. guide for the development of bicycle facilities 49 Intersecting Roadway Fig u re 22. Examp le of Adjace nt Path Intersection Complex Intersection Crossings Complex intersectio n crossings constitute all other path-roadway or driveway junctions. These may includ e a variety of co nf igurations at which t he path crosses d i rectly through an ex i stin g intersection betwee n two (or more) roadways and there may be any number of motor ve hicl e turnin g movements. Improveme nts to co mp l ex c ros si ngs mu st be co nsidered o n a case-by-case basis. So me suggested treatments which m ay be co nsid - ered include: (1) move the c ro ss in g, (2) in stall a sig na l , (3) c hange signalizatio n timing, or (4) pr ovide a refuge island and m ake a two-s tep c rossing fo r path users. Parti cu l arl y for co mp l ex intersec tion c ross in gs, it i s critica l t hat the des igner treat eac h situ at io n as a unique cha ll enge which req u i res creat ivity as we l l as so und engin eeri ng jud gment. T he safe passage of all modes through the intersection is the goa l to be ac h ieved. Assigning Right of Way Volume, spee d and highway classification sho ul d not be the only crite r ia to co nsider when ass ignin g ri ght of way at a path crossing. Th e co mfort and conve ni ence of t he pat h user, and t he uniqu e behavioral character- i stics of t he path user and motorist alike, mu st al so be taken into consideration. Regarding behavior, it mu st be recog niz ed that some path users may have: '.) very low delay tolerance :J a st ro ng desire to mai ntain mom entum Design Shared Use Paths 50 guide for the development of bicycle facilities Design Shared Use Paths .) I ittl e traffic know ledge (part i cular ly c hildren) ) so metim es a "regu lation s don't app ly to me" mentality Assig nin g incorrect prior ity or being overly restrictive in an atte mpt to protect the path user can lead to confusion and unsafe pract i ces by bot h pat h users and motorists, increasing the pote nti al for a co lli sio n. Other Intersection Design Issues Regardless of the type of pat h-roadway inte rsection , there are severa l other design issues to co nsider. Traffic Signa ls/Stop Sign s: A reg ul atory traffic control device sho uld be insta ll ed at all path-roadway intersecti o ns. Warrants from the MUTCO 2 co mbin ed w ith sou nd engin ee rin g judgment should also be co nsid ered when determ in i ng the type of traffic contro l device to be installed. Traffic signa l s fo r path-roadway interse ctions are appropriate under cer- ta in c ir c um stances. The MUTCO 2 lists 11 warrants for traffic signa ls, and although path crossings are not addressed, bicycle traffic on the path may be f un ction all y classif ied as vehicu lar traffic and the warrants ap- p li ed according ly . Fo r manually-operated signal actuation mec hani sms , the bicycl ist signa l b utto n should be loca ted in a position that is eas i ly access ibl e from the p ath and 1.2 m (4 feet ) above the grou nd , so that bicyclists w ill not have to di smount to activate t he signal. Anot her method of act iva tin g the sig- nal is to provide a detector loop in t he path pavement; however, th is must be supp leme nte d with a m anual ly-activated signa l, si nce th e loop detector wi ll not respond to pedestrians. On signa li zed div ided road- ways, a pu sh button sho uld al so be located in th e median to acco unt for those path users who may have been t rapped in t he refuge area. Path stop sig ns should be p laced as cl o se to the intended stopp in g po int as po ss ibl e, and shou ld be suppl emented w ith a stop bar . Fo ur-way stops at path-roadway intersections are not recom mend ed because of frequent co nfu sion abo ut o r disregard for right of way rul es. Yield signs may be acceptab le at so me locat io ns, such as lo w -vo lum e, l ow-speed neighbor- hood streets. Sign type, size and location sho uld be in acco rd ance w ith the MUTC0 2 • Care sho uld be taken to ens ur e that shared use path sig ns are located so that motorists are not confused by them , and that roadway sig ns are p l aced so that b icycl i sts are not co nfu sed by them . Transition Zones: Where shared use pat hs terminate at ex istin g roads, it is important to integrate the path into the ex i stin g system of roadways . Care shou ld be taken to proper ly des ign the termin al s to transition the traffic into a safe merg in g or d iverging sit uat io n . Appropriate sign ing is necessary to warn and direct both bicycli st s and motorists rega rdin g these transition areas. W ith t hi s in mind , the designer should co nsid er each path-roadway in- te rsect io n along the lengt h of the pa t h as a potential entry/exi t po int. guide for the development of bicycle facilities 51 Intersectio n desi gn shou ld also consider the movements of path users who either enter the path fr om the road , o r plan to exi t th e path an d use the roadway for the rem ain de r of their trip . Sig ht Distance: Si ght di stance i s a principa l e leme nt of ro adway and path intersect ion des ign . Th ere are gene rall y three sight di stance issues that apply to jun ctio ns: (1) stopp in g sight distance, (2) intersect i o n sig ht di sta nce, and (3 ) decisio n sight distance. Stopping sight d ista nce is covere d by Fi gure 19 and Tab l e 3 of this c hap- ter , alon g with the accompa nying text in that sec ti on . Improv in g appropriate intersection si ght distances for approac hin g motorists ca n in c rease t he likelihood th at they wi ll notice pat h users w ho are ap- proaching the intersection . This ca n be ac hi eved by in creasing the standard perception-reac tion time va l ue of 2.5 seco nd s for moto rist s' stopping sight distance or by usin g the most appropriate decision sight distan ce va lu e from Table 111 -3 in the AAS HTO Po l icy o n Geometric D e- sign of Hig hways and Streets (Green Book 1), altho ugh non e of the se specifica ll y address pat h c rossings . Decision sig ht distance may al so be app li ed to bi cyclists, but differs in concept fro m th e motorist-based application. For bicycl ists , it involves providing cl ea r sight lin es th at are based o n th e distances th at approac h- in g motor ve hi cles w ill travel in the amo unt of tim e a bi cyclist takes to f ull y clear th e intersect ion from a "stop-go " decision po int lo cated at th e stopping sight distance fro m the pavement edge. This co ncept ack nowl - edges bicycli sts' desire to m aintain momentum . Approach Tr eatments: Shared use path intersections and approac hes sho ul d be on rel ative l y fl at grades . Stoppin g si ght d istan ce at inters ec- tions shou ld be eva lu ated and adequate wa rnin g signs shou ld be provided to all ow b icyclis ts to stop before reac hin g the intersection, es- peciall y o n downgrades . Un paved shared u se p at hs should be p ro v id ed w it h paved aprons exte ndin g a minimum of 3 m (10 feet ) from paved road surfaces. Ramp Widths: Ramps for curbs at intersect io ns shou ld be at least th e same w idth as th e shared u se pat h. Curb c uts and ramps should provide a smooth trans iti on betwee n th e shared use path and the ro adway . A 1 .5 m (5-foot) rad iu s or flare may be conside red to fac ilitate ri ght turns for bicy- cles . This sa me co nsid era tion co uld al so be app li ed to intersectio ns of two shared use paths. Refuge Islands: Refuge i slands shou ld be co nsidered for path-roadway interse ct ions in wh ic h o ne or more of the fo ll ow in g app ly: (1) high vo l- um es of roadwa y traffic and /or speeds create un accep tabl e cond ition s for path use rs, (2) roadway width is excess i ve give n t he avai lable cross- in g time , o r (3) the cross in g w ill be used by a num be r of people who c ross more slowly, suc h as the elde rl y, sc hoo lc hil dren, persons with dis - abi I ities , etc. The refuge area shou ld be l arge enoug h to acco mm odate p latoons of us- ers, including groups of pedestrians, gro up s of bi cy cli st s, ind ividua l t and em bicycles (wh ic h are co nsid erab ly longe r than stand ard bicycles), Design Shared Use Paths 52 guide for the development of bicycle facilities Design ~L W (offset) = ~ For Metric Units : wv 2 L = 155 , where V < 70 km/h whee l chairs , peop le with baby st ro l lers and eq uestrians (if t hi s is a per- mitted path use). The area m ay be desig ned with the storage al igned across t he i sla nd or longi t udin a ll y (see exa mpl e in Fi gure 23). Adeq uate space shou ld be provided so th at those in t he refuge area do not fee l threa te ned by pass i ng m o tor ve h icles wh il e wa itin g to finis h th e cross- ing. Cut-through at grade X = Length of island shou ld be 2 m (6 ft) or greater Y = Width of refuge : 2.0 m (6 ft) = poor 2.5 m (8 ft) = satisfactory 3.0 m (1 Oft) = good L = 0 .62 WV , where V 2': 70 km /h For English Units: wv 2 L = 60 , where V < 45 mph L =WV, where V 2': 45 mph Figure 2 3. Specification for a Created Refuge Area Shared Use Paths guide for the development of bicycle facilities 53 Signing and Marking Adequate sig nin g and mark in g are essentia l on shared u se paths, es pe- cial ly to alert bicyclists to potential co nfli cts and to co nvey regulatory messages to both bicycl ists and motori sts at hi ghway intersect ions. In ad- dition , guide signi ng, such as to indi cate directions, destinations, distances , route numbe rs and names of c ro ss in g streets, should be us ed in the same manner as o n hi ghways. In ge nera l , uniform app li catio n of traffic contro l devices, as described in the MUTC0 2 , provides minimum traffic cont rol measu res w hi ch should be app li ed. A designer shoul d cons id er a 100-mm (4-inc h) w ide ye ll ow center line st rip e to sepa rate op po site direct ion s of trave l. Thi s str ipe should be bro- ken where adequate passing sight distance exists, and so lid in other locations, o r where pass in g by bicycles sho uld be discou raged. This may be particu larly beneficia l in the fol l ow in g ci rc um stances: (1) for heavy vo lum es of bicycles and /or other use rs, (2) on cu rves wi th restricted sig ht distance, and (3) on unlighted pat hs where ni ghttim e ridin g i s expec ted . White edge lines can al so be very beneficial where bicycle traffic is ex- pected du ring ear l y eve nin g hours. General gu id ance on sig nin g and marking is provided in th e MUTC0 2 • Care shou ld be exerc ise d in the choice of pavement marking mater ial s. Additional signin g can also be hel pful to enco urage use rs to share t he path and fo llow path use r etiqu ette such as givin g audib le signa l s before passing on th e left. Wa rnin g signs sho uld also be used in areas where th e recommended criteria herein ca nn ot be met due to phys ica l const rai nts. Reduced ve rsions [450 mm x 450 mm (18" x 18")] of the signs in Section 9B-l 3 of the MUTCD 2 may be used to warn users of sha rp c urves, inter- sections , etc. Pavement m ark ings at a c ro ss in g sho uld accomplish two th in gs: cha nn el path users to c ross at a clear l y defin ed loca ti o n and provide a cl ea r mes- sage to motorists that this particular sect i o n of the road mu st be sha red with other users. For the pat h user , stop sig ns, stop bar pavement markings, yie ld sig ns, ca uti on sig ns or other dev ices should be used as app li ca bl e. For a roadway user , a clea r message mu st be presented in a l oca tion where it wi ll be seen by th at user. Traditio nal tr ea tm ents have included the bicycle c ro ssing sign (Wll -1), the pedestrian crossi ng sign (WllA-2), the pedestrian c rosswa lk lin es [do ubl e 150-mm (6-in c h) lines spaced not less than 1.8 m (6 feet) apart], or fl ashi ng ye ll ow li ghts at the crosswa lk . H owever, si gns are freque ntl y p l aced at th e side of the ro ad, out of mo- tori sts' line of sight, and hi stor i ca ll y, fl as hin g ye ll ow li ghts have also been used at non-crosswa l k app li cations . In recent yea rs, new app li ca- tions have been deve loped , includ in g the fo ll owing, whi c h may be suitable for urb an and suburb an sett in gs, but ma y not be su itab le for rural areas: ) "Zebra-s tyl e" or co lori zed pavement c ro sswalks, which are far more visible than traditional des igns. Design Shared Use Paths 54 guide for the development of bicycle facilities Design Shared Use Paths J Raised platform crosswa lks, which ca n be usefu l to define roadway space for non-motorized users and stress the need for motorists to y ield to that space. 0 Pedestrian-friendly intersection cross in gs, which incorporate ap- propriate signa l heads and infrared motion detectors , pressure mats or other technologies. J Midblock neck-downs or intersection c urb -bu l bs at the crossing to shorten the crossi ng distance . The above suggestions should be considered on a case-by-case basis and should al ways be eva lu ated w ith regard to the safest overall method for accommodating both path us ers and roadway users. Pavement Structure Hard, all-weather pavement surfaces are usually preferred over those of cr u shed aggregate, sand , clay or stabilized eart h sin ce these mater i als prov id e a much l ower level of service and require higher maintenance . However, operating agenc ies that have c hosen crushed aggregate as their surface material have found that they can achieve a comp leted path in less time and at less cost than with aspha lt or concrete. A l so, they have found that skaters were not drawn to the path , and bicycl ists ' speeds were lower, making the path more comfortab le for other users. In areas that are subjected to frequent or even occasional flooding o r drainage problems, or in areas of steep terrain , unpaved surfaces wi ll often erode and are not recommended. Good quality all-weather pavement st ructures can be constructed of as- pha lt or Portland cement co ncrete . Because of wide variat ion s i n soi l s, loads , materials, construction practices and varying costs of pavement materials, it is not practica l to present spec ifi c o r recommended typical str uctura l sections that wi ll be applicable nationwide. In areas where cli- mates are extreme, the effects of freeze-thaw cycles should be ant icipated in the design phase. Atten t ion to local governi ng co nd iti ons and the principles outlin ed in this section is needed . Experience in high- way pavement, together with sound engineeri ng judgment, ca n assist in the se l ection and design of a proper path pavement structure and may identify energy-conserving practices , such as the use of su lfur-extended asp halt, asp halt em ul sions and fused waste. Designing and se lect in g pavement sectio ns for shared use pa t hs is in many ways simi l ar to designing and selecti ng highway pavement sec- tions. A soils investigation sho uld be cond ucted to determine the load- carry in g capab iliti es of the nati ve soil , unimproved shou ld er or former railroad bed (if ballast has been removed), and t he need for any special provisions. While loads on shared use paths will be substantia ll y less than highway lo ads, paths should be designed to sustain without damage wheel loads of occasional emergency, patrol , maintena nc e and other motor vehicles expected to use or c ro ss the path. guide for the development of bicycle facilities 55 It is important to construct and maintain a smooth ridin g surface on shared use paths. Pavements shou ld be machine laid ; soil sterila nts shou ld be used where necessary to prevent ve getati on from er upting t h rou gh the pavement. On Port l and cement concrete pavements , the transverse jo i nts , necessa ry to co ntrol crack i ng , should be saw cut to pro- v ide a smooth rid e. On the other hand , skid resistanc e qualiti es sho ul d not be sacrif i ced for the sake of smoothness. Broom finish or burlap dra g concrete su rfaces are preferred . When motor vehicles are driven on shared use path s, their wheels often wil l be at or very ne ar the edges of th e path. Since this can cause edge dama ge that, in turn , wil l reduce the effec t i ve operating width of t he path , adequate edge su pport shou l d be provided . Ed ge su pport ca n be ei- t her in the form of stab il ized shou lders or construct i ng additio nal pavement w idth or thickness . Constructing a typical pavement w idth of 3.0 m (10 feet), where ri ght-of-wa y and other conditions permit, le sse ns t he edge rave li ng prob lem and offers two additional advantages over shou lder co nstruction on shared use paths . Fi rst, it allows additional ma- neuvering space for bicycl i sts, and second, the additio nal construct ion cost can be l ess than the cost of constructing shoulders becau se a se pa- rate construction operation is el i minated . At unpaved hi ghway or dr iveway crossings of shared use paths , the high- way or driveway shou ld be paved a minimum of 3 m (10 feet ) on eac h side of the crossing to reduce the amount of gravel being scattered alo ng t he path by motor vehicles. Th e pavement structure at th e cross i ng should be adequate to sustain the expected loading at that location . Structures A n overpa ss, u nderpass , br idg e or facility on a hi ghway brid ge may be necessary to p rovide co nt i nuity to a shared use path . An example of a small bridge st ructure used to provide path cont i nuity is shown in Fi gure 24. A bicycle facility on a h ighway structure is shown in Fi gure 25. O n new struct u res , the min i mum clear width should be the same as t he approach paved shared use path , p l us t he min i mum 0.6-m (2-foot) wide clear areas. Car rying the clear areas across the structures has two adva n- tages. Fir st, the clear width provides a min i mum hor izontal shy di stan ce from t he railin g or barrier, and second, it provides needed maneuverin g space to avoid conflicts with pedestri ans and other bicyclists who are stop ped on the bridge. Access by emerge ncy, patrol and mai ntenance ve hicles should be cons idered in estab l ishin g the des ign clearances of structures on shared use paths . Si mi l arl y, vert i ca l clearance ma y be d ictated by oc- casional moto r vehicles using the path. W here prac tica l , a vertica l clearan ce of 3 m (10 feet) is desirab le for adequate vertica l shy di sta nce . Ra ili ngs , fences or barriers on both sides of a path on a structure shou ld be a minimum of 1.1 m (42 in ches) hi gh . Fi gure 24. Brid ge Struct ure to Prov id e Bike Path Co nt inuity Design Shared Use Paths 56 guide for the development of bicycle facilities Figure 25. Shared Use Path (far Right) on a Grade Separation Structure; Note Bike Lane and Sidewalk. Design Shared Use Paths Bridges shoul d be designed for pedestrian li ve loadings. Whe re mainte- nance and emergency vehic les may be expected to cross the bridge, the des ign should accommodate them. On all bridge decks , specia l ca re should be taken to ensure that bicycle-safe expa nsion joints are used, and that decking materials that become sl i ppe ry when wet are avoided. Where it is necessary to retrofit a shared use path onto an exist in g high- way bridge , several alternatives should be considered in light of what the geometr ics of the bridge will allow. One option is to carry the shared use path across the bridge on one side. This shou ld be done where 1) the bridge fac ility wi ll connect to a path at bo th ends, 2) suffi c ient width ex ists on that side of the br id ge or ca n be obtai ned by widening or restriping lanes, and 3) provisions are made to physically separate bicycle traffic from motor vehicle traffic as discussed previously. A second option is to prov ide e ith er wide c urb l anes or bicycle lanes over the bridge. This may be advisable where 1) th e shared use path tran- sitions into bicycle l anes at one end of the br idge and 2) suff ic ient w idth exists or can be obtained by widening or restriping. This option should on ly be exerc ised if the bike l ane or wide outside l ane can be accessed without in creasing the potential for wro ng-way rid in g or inappropriate cross in g movements . Because of the large number of variab les invo l ved in retrofitting bicycle faci liti es onto ex isting bridges, compromises i n desirable design cr iteria are often in ev itab le. Therefore , the w idth to be provided is best deter- mined by the designer, on a case-by-case basis , afte r thoroughly co nsid ering all the variab les. Drainage The recommended minimum pavement cross sl ope of 2 percent ade- quately provides for drainage . Sloping in one direction in stead of crowni ng is preferred and usu all y simp lifies th e drainage and surface co nstru ct ion. A smooth surface is essentia l to prevent water ponding and ice formation . On unpaved shared use paths, pa rticular atte ntion should be paid to drainage to avoid erosion. Where a shared use path is constructed on th e side of a hill , a ditch of su itabl e dimensions shou ld be placed o n the uphill side to intercept the hillside drainage. Such ditches shou ld be des igned so that no undue ob- stacle is presented to bicyclists . Where neces sary, catc h basins with drains shou ld be provided to carry the intercepted water under the path. Drainage grates and manho le covers sho uld be located outside the travel path of bicyclists. To assist in preventing erosion in the area adjacent to the shared use path, the design should include considerat ion s for pre- serving the natural grou nd cover . Seeding, mulching and sodding of adjace nt slopes, swales and other erod ibl e areas should be in c l uded in the project plans. Also see Chapter 2, Shared Roadways , for inform at ion on drainage grates. guide for the development of bicycle facilities 57 Lighting Fixed-source li ghtin g improves visib ility along paths and at in tersectio ns. In addition, li ghti ng all ows th e bicycl ist to see the path d irect ion , surface co nditi ons and obstacles. Li ghti ng for shared use paths i s important and should be co nsid ered w here ni ght usage is expected , suc h as paths se rv- in g college students o r comm uters, and at hi ghway intersectio ns. Li ghtin g sho uld also be co nsid ered t hrough underpasses or tunnels , and when nighttime security co uld be an issue. Dependin g o n the locatio n, ave rage maintained horizontal illumination levels of 5 lu x to 22 lu x should be co nsid ered . Where specia l sec uri ty prob lems ex i st, hi gher i llu- min ation leve ls may be co nsid ered. Li ght standards (poles) should meet the recomme nded ho ri zo ntal and ve rti ca l clearances. Luminaires and stand ard s should be at a sca le approp ri ate for a pedestrian. Restriction of Motor Vehicle Traffic Shared use paths may need some form of p hys ica l barrier at highway in- tersections to prevent un auth orized motor vehicles from using the facilities. Prov ision s can be made for a lockab le, removable (or reclining) barrier post to permit entrance by authori zed ve hicl es. Posts or bol lard s should be se t back beyo nd the clea r zo ne o n the crossing hi ghway or be of a breakaway design. The post should be permanently refl ec torized fo r ni ghttime v isibility and painted a bri ght co lo r fo r improved daytime vis i- bility. Striping an enve lope aroun d th e post i s recommended as show n in Fi gure 26. When more t han one post is used, an odd nu mber of posts at 1.5-m (5-foot) spacing is desirable. Wider spaci ng can allow entry to mo- tor vehicles, while narrower spac in g might prevent entry by ad ult tricycles , whee l chair users, and b icycles w ith trailers . 0 .3 m (1 ft) 0 .3 m (1 ft) 1111 -----3m .., ( 10 ft) Figure 26. Barrier Post Striping Bike Path r Center Line Stripe An alternative method of rest ri cti ng entry of motor vehicles is to sp l it the entry way into two 1 .5-m (5-foot) sect ions separated by low l andscapi ng. Emergency ve hicl es can st ill enter if necessary by strad dling the land- sca pin g. The hi gher maintenance costs assoc iated w ith l andscapi ng should be ac kno wledged before t hi s alternat ive method is se lected . Design Shared Use Paths 58 guide for the development of bicycle facilities Design Shared Use Paths Undesirability of Sidewalks as Shared Use Paths Util iz in g or providing a sidewalk as a shared use path is un sa t isfactory for a va ri ety of reasons . Sidewalks are typica ll y designed for pedestrian speeds and m aneuverab ility and are not safe for hi gher speed bicycle use. Conflicts are common between pedest rian s traveling at low speeds (ex itin g stores, parked cars, etc.) and bicyclists, as are confl icts with fixed objects (e.g ., parking meters , utility poles , sig n posts , bus benches, trees , fire hydrants , mail boxes, etc.) Walkers, j oggers , skateboarders and roller skaters can, and often do, change their speed and direction alm ost instantaneously, leaving bicyc l ists insufficient reaction time to avoid co l- lisions . Simil arl y, pedestrians often hav e difficu lty predicting the direc tion an o ncomin g bicyclist wi l l take. At intersecti ons, motorists are often not looking for bicyclists (w ho are traveling at hi gher speeds than pedestri- ans) enter in g the crosswalk area , particular ly when motorists are making a turn . Sight distance is often impa i red by buildings, wal l s, property fences and shrub s along sidewalks, espec iall y at driveways . In addition, bicyclists and pedestrians often prefer to ride or walk side-by-side w hen traveling in pairs . Sidewalks are typically too narrow to enab le this to oc- c ur without serious co nfli cts betwee n users. It i s especial ly inappropriate to sign a sidewa l k as a shared use path or designated bike route if to do so wou l d pro hi bit bicyclists from using an alternate fac ility that might better serve their needs. It is important to recognize that the develop ment of extreme ly wide sid e- walks does not necessari ly add to the safety of sidewalk bicycle travel. Wide sidewalks might enco ura ge higher speed bicycle use and can in- crease potential for conflicts w ith motor ve hicl es at intersections, as we ll as w ith pedestrians and fixed objects. For guidance on whe n and how to des ignate sid ewalks as sig ned bikeways, see page 20. Shared Use with Motorbikes, Horses and Snowmobiles Even where lawful , it is undesirable to mix mopeds or motorbikes with bicycles and pedestrians on the same faci l ity. In ge neral , mopeds shou ld not be al lowed on shared use paths because of conflicts with the slower moving bicyclists and other user s. Mopeds al so diminish the qu iet, relax- ing expe ri ence most use rs desire on sha red use paths. In some cases w here an alternate route for mopeds does not ex ist , ad ditiona l width, signin g and striping shou ld be used to m inimi ze conflicts . In creased pa- trolling by l aw enforceme nt personnel is al so recommended to enforce speed limi ts and other rules of the road. It is usually not desirable to mi x horse riding and bicycle traffic on the same shared use path. Bicyclists are ofte n not aware of the need fo r slower speeds and additiona l operating space near horses . Horses can be start led eas il y and may be unpredictable if t hey perceive ap proa c hin g bi- cycl ists as a danger. In addition , pave ment requirements for bicycle guide for the development of bicycle facilities 59 travel are not suitable for horses. For these reasons , a bridle trail sepa rate from the shared use path is recommended to accommodate horses . In winter spo rt s areas during the winter months there is usually insuffi- cient bicyc le traffic to justify plowing snow , and manage rs of shared use paths may all ow them to be used by cross co untry skie rs or snowmob il e operators . Design Shared Use Paths 60 guide for the development of bicycle facilities Design Other Design Considerations Other Design Considerations Railroad Crossings Railroad-highway grade cross in gs shou ld idea ll y be at a right ang le to the rails . This can be accomp l ished either as a sepa rate path or a widened shoulder, as shown in Figure 27. The greate r t he crossing dev iates from this idea l crossing ang le, the greater is t he potentia l for a bicycl ist's front whee l to be trapped in the flangeway , c aus in g loss of steeri ng control. If the crossing angle is less t han approximate l y 45 degrees, an add iti onal paved shoulder of sufficient w idth should be provided to permit the bicy- clist to cross the track at a safe r angle, preferab l y perpendicularly. Where this is not possible, and whe re t rain speeds are low, comme rc ial ly avail- ab le compress ibl e flangeway fi ll ers may enhan ce bicyclist operat ion. It is al so important that the roadwa y approac h be at the same el evation as the rails . Co nsideration shou ld be give n to the crossi ng surface materia ls and to t he flangeway depth and width . Rub ber or co ncrete crossing mater ials are longer lasti ng than wood or as ph alt and require less maintena nce. In some cases , abandoned tracks can be removed. Warning signs and pavement markings should be installed in accordance with the MUTCD 2 • Bicycles on Freeways In some instances , bicycl i sts ar e perm itted to operate on freeways. Norma ll y, a freeway would not be signed or marked as a bikeway, but in some states it can be opened for use if it meets certain c riteri a. Essen- tia ll y, the c riter i a in volve assessing the safe ty and conve nien ce of the freeway compa red with ava ilabl e alternate routes. However, a freeway shou ld not be avai l ab le to bicycle use i f it is determ in ed to be in compat i- ble. If a suitab le alternate route ex ists , it wou ld normally be unnecessary to open the freeway to bicycle use. Howeve r, if alternate routes are un suit- able for bicycle trave l, the freeway ma y be a better or the o nly alternative for bicyclists . In determ inin g th e su itabi l ity of an alternate route , safety shou ld be the paramount co nsid eration. The fo ll owing factors sho uld be co nside red: ) Number or frequency of intersections ) Shou ld er width on roadway and across stru ctures ) Traffic volumes ) Ve h icle speeds ) Bus , truck and recrea tion al vehicle vo lu m es ) Grades ') Travel time 45° Crossing (acceptable) ~. . \ . . \ .. ~ ,~ .~ • 0-\~ \ . . \ . \ \ . . \ guide for the development of bicycle facilities 61 NOTE: Additional width to 4 .2 m (14 ft) to be provided at railroad crossing to allow cyclists to choose their own crossing routes . Figure 27. Railroad Crossings Widened Shoulder cu rve Widening Bil<eway Shoulder 90° Crossing (most desirable) \ AddllJOnal ,,...-A/W \ required \ ' Bikeway Curve widening Design Other Design Considerations 62 guide for the development of bicycle facilities Design Other Design Considerations When a suitab le alternate route does not exis t, a freeway sho uld er may be cons id ered for bicycle t rave l . Normally, fr eeways in urban areas w ill have characte ri stics making them hi ghly undesirable to pe rmit bicycle use. In determining if the freeway shoulder is suitab le for bicycle travel , the following factors should be considered: ) Paved shou lder widths [a minimum of 1 .5 m (5 feet) of rid ab le space , free of rumble st rip s] ) Sho uld er surface cond iti o ns (drainage grates, expa nsion joints, rumble st rips , cracks, etc .) ) Number and l ocat io n of entrance/ex it ramps ) Design of exit ramps ) Traff ic vo lum es on entran ce /exit ramps => Truck vo lum es ) Grades W hen bicyclists are perm itted on segments of freeway , it wi ll be neces- sary to modify and supp l ement freeway regu l atory signs, particularly those at freeway ramp entrances. W here no reaso nab le alternat ive exists within a freeway cor ridor, alter- natives shou ld be developed to improve ex isti ng routes or provide a para ll el se parated bikeway within o r adjacent to th e freeway right-of-way . The long-te rm goa l should be to prov ide a safe and conve- nient non-freeway route for bicycle trave l. Bicycle Facilities through Interchange Areas Turning roadways prov id ed for interchange ramp in gress and egress of- te n require bicyclists on th e c ro ss streets to perform merging, weaving or crossing maneuvers with ramp vehicles. These conflict poi nts are made cha ll eng in g w hen a wide disparity in spee d exists between tr aff ic on th e ra mp and cross street bicycle tr affic crossi ng the ramp , and when grade separations c reate significa nt profile gra d ie nts. If a bike l ane or route must traverse an interchange area , these intersect ion or co nfli ct points sho uld be designed to l im it the conflict areas or to elimin ate unn ecessa ry uncontrolled ramp connection s to urban roadw ays. One possib le method of delineating a bike lane through t he enti re inter- cha nge area across the turn in g roadway interse ct ion s is shown in Fi gure 28, Option 1. When it is mo re desirable to all ow the bicycl ist to c hoose his/her own merge , weave or crossi ng maneuvers, it is recommended that the pavement markings be discontinued throu gh the c ro ssi ng area, as depicted in Fi gure 28, Option 2. In the case of a bike lane alon g the shou ld er of a freeway, these sa me two methods of de l ineatin g the bike l ane throug h th e intercha nge area ca n be guide for the development of bicycle facilities 63 used . In add iti on , if the freeway interchange with the c ross roadway i s a standard diamond-type, anoth er alternat ive wou ld be to continue the freeway sho uld er bike l ane al ong the sho uld ers of the ramps through the cross road intersectio n . This would be particularl y appropriate if the c ross road was a potential bicycle destination access ro ad . Option 1 Option 2 Figure 28. Bicycle Crossing of Interchange Ramp Cross Street Cross Street Design Other Design Considerations 64 guide for the development of bicycle facilities Design Other Design Considerations Bicycles at Modern Roundabouts Generally there are three ways to ac c om mod ate bicyclists in round- abo uts: 1) in mi xed flow with vehicular traffic, 2) along sepa rate bicycle paths, and 3) on bicycle l anes along the outs id e di ameter of round abo uts (not cu rr entl y recom mend ed). The fo l lo w in g safety issues should be cons id ered when co ntemp l at i ng bicycles in roundabouts: ) Bicyclists are vulnerab le users of roundabouts and co nsid erat i o n should be give n for their accommodat i on . ) In low-speed [approxi mate l y 20 km /hr (12 mph )], si ngl e-lane round abouts, few negat ive safety impa cts have been observed w hen bicycles are mixed in the traffic stream . Because of the small spee d differentia l , bicyclists are expecte d to circulate in th e tr affic l ane at ap pro xima tel y the same speed as vehicles . When bike l anes l ead to this type of roundabout, it is preferable to disco ntinu e them 10 to 20 m (35 to 65 fe et) before reac h in g th e roundabout, rath er than co ntinuing the l ane th rough the roun dabo ut. ) Bicycle safety tends to deteriorate at hi gher speed, mu lti-l ane roundabouts and at fl ared entries. At th ese roundabouts , spec ial so l utions should be sought w hen wa rranted by bicycle vo l um es. A mong th e possible so l uti ons are sepa rate bikeways, shared use of th e pedest ri an faci I ity, separate b i ke routing through oth er intersec - tions , or grade separa tion for the vu ln erabl e modes. A majority of b i ke c ras hes at round abo uts invo lve entering veh icl es and ci rc ul at in g bicycles, reinforcing the need to reduce enter in g spee ds by providing ampl e deflection, to mainta in goo d vi sibility for enter in g traffic and to enforce y ield co nditions for enteri ng tr aff ic. Traffic Signals At sig nalized intersect ion s where bicycle traffic ex i sts or is anti cipated, the t i min g of the traffic signa l cycle, as we ll as th e method of detecting the pr ese nce of the bicyclists, should be co ns idered. In mixed traffi c flow the bicyclist norm al ly ca n cross the intersect ion under the same sig nal phase as motor vehic les. Th e greates t risk to b icyclists i s during the cl ea r- ance interva l and during the actu ated phases during pe riods of low tr affic flow. Signals should be des igned to prov id e an adeq uate clearance inter- va l for bi cy cli st s w ho enter at the end of th e gree n and a tota l cross i ng time (minimum green p lu s clearance interva l) l ong enough to acco mm o- date b icycl is t s start in g up o n a new green. Th e lengt h of the ye ll ow c hang e interval is dependent upo n the speed of app roac hin g traffic.Ye ll ow c hange interva l s adequate fo r motori sts (ge n- eral ly 3.0 s to 6.0 s) are usua l l y adequate for bicyclists. Generally, an all -red cl ea rance interva l is not required, but can be used to al low the cy - clist w ho entered the intersec tion dur i ng the ye l l ow interva l to clear the guide for development of bicycle facilities 65 intersectio n b efo re the conflicting movement receives the green sig n al. The all-red clearance i nte rval norma ll y ran ges from 1.0 s to 2.0 s. The to- ta l cleara nce i nterva l (ye ll ow c hange i nterva l p lu s red clearance interva l ) can be calcu l ated from:12 Fo r Met ri c Uni ts: v w+I y+rclea< ~t ,+ 2b +-v- where: y =yellow interva l(s) rc1 .. , = red c lea rance interv al(s ) t, = react ion time (1 .0 s) v = bicycl ist speed (mi s) b =bicyc li st braking deceleration (1.2 to 2.5 mi s') w = wid th of crossin g (m) = bicycle length (1 .8 m) Fo r En g lis h Uni ts : v w+I y + rcl ear ~ t , + -+ --2 b v y =ye ll ow interval (s) rc1 .. , = red c leara nce interva l(s) t, = react ion time (1 .0 s) v = bicyclist speed (mph ) b =bicycli st brak i ng dece lerat ion (4 to 8 ft/s ') w =width of crossin g (ft) I = bicycle length (6 ft) If fie ld observations are no t ava il ab l e, approxi m ately 98 percent of cy- clists shou l d be able to clear signa l s timed fo r the follow i ng speeds: 19 km/h (5.3 m/s) (12 mph (17.6 ft/sec)] for Gro u p A cycl i sts , 13 km/h (3.6 m/s) (8 mp h (12.0 ft/sec)] for Gro u p B cyclists, and 10 k m/h (2.8 m/s) (6 mph (9.1 ft/sec)] for Group C cyclists. Approx i mately 85 percent of cy- cl ists can clear signa l s timed for speeds 20 pe rcent hi gher. If loca l practi ce does not permit th is long a red clearance inte rva l (as g ive n b y the equation), th e lon ges t red clearance inte rva l co ns istent with loca l practice sho ul d be used. When an approach rece ives a gree n signa l , t h e bicyclist n eeds enoug h time to reac t, accelerate and c ross the intersect ion. The ge neral equation to determine the minimum green t i me is :1 2 For Met ric Unit s : v w+I g + y + rclear ~ tcross = t, + -+ --2a v wher e; g =min im um gree n y, rc1 .. , = ye ll ow and red clearan ce intervals act ually us ed t''°" =Time to cross th e i nters ec tion t, =React ion tim e (2.5 s) v = Bicyc le speed (mi s) a = Bi cyc le accelerat ion (0.5 -1 .0 mi s') w =Width of crossi ng (m) I = Bicycle lengt h (1 .8 m) Fo r En g lis h Unit s : > _ v w+I g + y + rclear -tcross -t, + -+ --2a v g = minim um gre en y, rc1.., = ye llow and red clearance interva ls ac tu all y used t"0 " =Time to cross the in tersection t, = Reaction tim e (2 .5 s) v = Bi cycle speed (ft/s) a = Bicyc le acceleration (1 .5 - 3 ft/s ') w = Width of crossin g (ft) = Bi cy cle length (6 ft) H owever, as with all ca l c ul ated signa l t i ming, actual fie ld observat io n s shou ld be u ndertaken prior to making any adjustments to the minim u m green or clearance interva l s. Acute angle i ntersections require lo nge r c rossin g times for bicycl ists. Detection of bicycles at t raffic-actu ated signa l s is cruc i a l for bicyc li sts' safety and fo r compl iance with traffic laws. Detectors t h at have bee n p laced for ve h icular traffic can usua ll y detect the prese n ce of bicycles . Quadrupo le and diagona l -type loop detectors a re examp les of i nductio n Design Other Design Considerations 66 guide for the development of bicycle facilities Design Other Design Considerations loops that provide bicycle detection . Dipo le and rectangular loops can also detect bicycles if the detector sen sitivity is adjusted. Efforts should be made to ensure that signa l detection dev ices are capab le of detec ting a bicycle and that the tota l green plus clearance time (ye ll ow plus all -red ) is suffic ient for th e bicyclist to cross the intersectio n safe ly. Detectors for traffic-actuated signa ls should be located in the bicyclist's expected path , i ncluding left-turn l anes and sho uld ers . It may also be he lpfu l to the bicyclist if the road surface is m arked to indicate the opt i- mum location for bicycle detection. Figure 29 shows the standard pavement symbo l which sho uld be placed at the location of a bicycle l oop detector to notify the cyclist where to stop. __., 1 ~ 50 m m (2 in) I 150 mr (6 in) • 125 mm (5 in) t ' 1 600 mm (24 in) j 50 mm (2 in) I t 150 mm (6 in) ------+----'---. --. 250 mm (10 in)~ Figure 29. Bicycle detector pavement marking In some situat ions, the use of pedestrian-or b icyclist-actuated buttons may be an acceptab le altern ative to the use of detectors provided th ey do not require bicyclists to dismount or make un safe leaning movements . However , act uated buttons should no t be co nsid ered a subst itute for de- tectors. guide for the development of bicycle facilities 67 Where programmed visib i lity signal heads are used , t hey shou ld be checked to ensure that t hey are visible to bicyclists who are properly po- sitioned on t he road . Obstruction Markings Vertical bar riers and obstructions , such as abutments, piers and other features ca u sin g bikeway constriction , shou ld be clearly marked to ga i n t he attentio n of approaching bicyclists. Thi s treatment shou ld be used on ly where t he obstruction is unavoidable, and is by no means a subst i- tute for good b i keway design. An examp le of an obstruction marki ng is shown in Fig ure 30 . Sig ns, reflecto rs, diagonal yellow mark i ngs or other t reatments m ay be app ropriate to alert bicyc l ists to pote nt i al obst ru c - t ions . Pier , abutment , grate , o r other obst ruction 150 mm (6 in) solid wh ite ma rking For Metric Units : L = 0 .62 WV , where Vis bicycle approach speed (km/h) For Eng lish Un its : L =WV , where V is bicycle approach speed (mph) Figure 30. Ob struction Marking Bicycle Parking Facilities Providing b icycle park i ng facilities is an esse nt ia l eleme nt i n an ove rall effort to pro mote bicycling. Peop l e are discou raged from bicycling u n- less adequate parking is avai lab l e. Bicycle park i ng fac il ities should be provided at both the trip origin and trip destination and should offer p ro- tection from theft and damage. The wide variety of b icycle park in g devices are generally grouped into two classes , lo ng-term and short-term . T he minimum needs for each differ in their p lacement and protection. Direction of bicycle travel Design Other Design Considerations 68 guide for the development of bicycle facilities Design Other Design Considerations Long-term bicycle parking facilities prov id e a hi gh degree of secur ity and protect ion from the weat he r. Th ey are intended fo r situatio ns w here t he bicycle is left unattended for l ong periods of time, such as apartm ents and co ndominium co mpl exes, sc hools, p laces of emp loyme nt and tran- sit sto ps. Th ese bicycle park i ng facilities are u sua l ly locke rs, cages or rooms i n buildings . Short-te rm fac iliti es provide a m eans of loc kin g the bicycle frame and both whee ls, but do not provide accesso ry and component secu rity or weathe r protection (u nl ess cove red ). They are for decentralized parking w he re the bicycle is left for a short period of time a nd is vis ibl e and con- ve ni e nt to th e building e ntran ce. Bicycle racks shou ld be d esig ned so that they: ) Do not bend w hee ls o r dam age other b icycle parts ) Accommodate hi gh sec urity U-shaped b i ke locks :) Accommodate locks sec u rin g t he frame and both whee ls (prefe ra- b ly without removing th e front whee l from the bicycle) ) Do not impede o r i nterfe re with pedest r i an traffic :) Are eas il y accessed from th e street and protected from m otor vehicles 0 Are vis ibl e to passers-by to promote usa ge and enhance sec uri ty ) Are covered w here u se rs will leave the i r bikes for a lo ng time ')Ha ve as few moving parts as possib le Facilities should be ab le to accommodate a wide ra nge of bicycle shapes and sizes , i ncluding tricycles and trailers if use d locally. Final ly , fac i l it ies sho uld be si mpl e to operate . If possible, signs depicting how to operate the faci l ity should be posted. Additional Bicycle Amenities Th ere are severa l other i mprovements that complement bicycle fac i l i- ties. For exa mpl e, turnouts or rest areas may be provided on long, uninterrupted shared use paths . Provisions shou ld be cons id ered for in- terfacing bi cycle travel with pub I ic trans it, such as racks on buses, bu ses co nverted to carry bicycles abo ard, or a llow in g bicycles on ferri es a nd rapid rai l fac i l ities. Printing and distributing b i keway maps is a hi gh -b enefit, low-cost p ro- ject that i s easi l y acco mp li shed. Maps ca n he l p bicyclists locate bikeways and parking fac i l ities and identify th e rel at ive suitab i li ty of dif- fe rent seg m ents of th e road sys tem . A lso , m aps ca n help b icycli sts avo id na rro w , h igh-speed, or h igh-vo l um e roads, one-way streets, barr iers a nd guide for the development of bicycle facilities 69 other proble ms. In ad dition , maps ca n provide in forma ti o n on Ru les of th e Road , bicycle safe t y t i ps and interfacing w ith mass tran sit. Accessibility Requirements Th e Americans with Disab ili ties Act (ADA) of 1990 is civ il ri ghts l eg isl a- tion that pro hib its discr im ination aga in st peop le with di sabi liti es. It guar antees the ri ght to part icipate fu ll y and equall y in all as pects of li fe. Accessibi I ity to transportat ion sys t em s mea ns pro v iding usab l e fac i I ities for the hig hes t num ber of people possible. A ccessib le features ca n benefit alm ost eve ryo ne. What is hel pfu l for a wheelchair use r, e.g., c urb ramps , w ill also benef it bicyclists. Low grades and cross slopes not o nl y make a faci li ty usa bl e for peo pl e with mob ility imp airments, but can also im prove a transportat ion ci rc ul ation sys t em for all pedes tri ans, b icyclis ts and inlin e ska ters. T here are 4 8.9 mi lli o n Am eri cans w ith disabi liti es; 70 percent of all America ns will at so me tim e in the ir li ves have a tem pora ry or perma nent disabi lity that makes suc h activ it ies as sta ir cl imbing i mposs i ble . People may hav e mobi lity, v isua l and cog nitive d isa biliti es that affect how usab le a faci li ty may be for them. As o u r populat ion grows older, the percentages of peop le w ith dis ab i lities wi ll increase . Wh at we build today w ill be w ith us for m any years . These des igns nee d to acco mmodate as m any use rs as poss ibl e. When choos in g bicycl in g or walk in g as a transportation mod e, users of- t en want a co nvenient, direct ro ute th at wi ll not exhaus t th e ir energy in ge ttin g to the ir destinat io n . Thi s ca n be espec iall y true fo r people w ith di sabi l ities. Saving energy often is th e reaso n a person c hooses driv in g over cycling and wa l ki ng. Designers of share d use paths need to keep in mind that we ll -designed accessib le fac il ities are usually more funct io nal fo r all users, with and w ithout disab ilit ies . Fede ral ADA standards have been deve lope d for bui ldings and th eir sites, but not for outdoo r deve loped areas. Some states and loca liti es have deve loped their own standa rd s for outdoor access ibility that mu st be followed. Federa l stand ard s fo r thi s deve lopment, w hi c h wou ld in- clud e shared use pat hs, are in the p rocess of being drafted by a Committee of Federa l age nc ies and interested organizat io ns. It is under- stood that co nstructing fac il ities in the o utdoors may have ce rtain l im itations t hat may make it difficu lt to build fu ll y access ibl e paths. The conditions t hat would p reve nt fu ll access ibility includ e thos e th at: :) Cause harm to signifi cant natural, c ultural , hi sto ri c or religio us characteri stics of a site :) Alter t he fundame ntal expe ri ence of the setting or intended p ur- pose of th e tra i I ) Require construct io n methods that are p roh i bited by federa l , stat e or loca l regu l at io ns ) In vo lve terrain c haracter isti cs (e .g., sl ope, soi ls, geologic or aquat ic) th at preve nt comp li ance with th e technica l prov isio n Design Other Design Considerations 70 guide for the development of bicycle facilities Design Other Design Considerations Many of th e provisions being developed by th e Regulatory Negotiation Co mmittee o n Outdoor D eve loped Areas, suc h as su rface treatment, minimum path width , c han ges in the l eve l surface , and passing space , wi ll automati ca ll y be met in the const ruction of a path suita bl e for bicy- cle travel. O nce these provisions are adopted , they should be cons ulted when de- sig nin g bi cycle faci l ities . W hat if an existing path i s not accessible? Do as mu ch as possib le to re- move th e barriers. Good signin g at the trai l access points that id enti fy si tu at io ns th at co uld be difficu lt to trav erse (s uc h as steep grade and c ross slope, narrow width and un eve n surface co ndition s) wi ll help use rs de- termine for themselves w heth er to use t he p ath . Rationale for Accessible Design Understanding ho w peop le with vario u s disabiliti es f un ctio n in th e o ut- doo r transportation environment is the fir st step in tr y in g to acco mmod ate th ei r design nee d s. Whee l chair Users-Low runnin g grades , preferably below 5 perce nt, are des irabl e because exert ion i s ne ede d to pu sh up , and co ntrollin g the w hee l c hai r goi ng down on steep grades i s a problem . Cross sl opes sho uld be no more than 2-3 percent. Th e grea t er th e cross slope th e greater the gra vi ty pull on the w hee lc hai r to turn into th e slope. Co mbinin g a steep runnin g grade with a steep cross slope increases the difficulty of m aneuve rin g a w hee l chair. On a hard ened o r paved surface , a 2 perce nt cross slope w ill drain off wate r in mo st cases . A meniti es, suc h as phones, water founta in s and pedestrian-actuated sig- na l co ntro l s, need to be placed no higher th an 2.4 m (4 fee t) from th e gro und leve l . Wheelchair us ers have a lower reac h range and a lower sight perspective of the environment. Th e buttons on actua ted sig nal s need to be l arge , protruding and easy to push for tho se who ha ve limited mobi l ity in their hands . Th e buttons al so nee d to be placed in an accessi - ble path of travel fo r a w heelc hair user . Vis ually Impaired-Most si ghted people ge t th e ir d ir ectio nal and spa ti al c ues vis uall y. Peop l e w ho are totally blind ge t th e ir cues from so und and touc h . Peop le with l ow v ision (78 perce nt of th e l egally blind popul a- tion) m ay have an addi tional advanta ge of detectin g co ntras tin g co lors . O lder peop le often lose their he ar in g and vision at the sa me tim e, creat- ing a co mpound difficu lty . O lder indiv idu al s, w ho lose th eir v isio n gra duall y, ma y not be tra in ed in wayfind ing tec hniqu es. Ca rs are gett in g quieter, curb radi i w id er, and street cross in gs lon ge r. A ll th ese factors co ntribute to a hos t ile pedestrian enviro nm ent, espec iall y fo r th e visually impaired . Curb ramps are typical ly thou ght of as an acco mmod ation for bi cycl ists and whee lchair use rs, but th ey ca n be use d by the visual l y imp aired as a wa rnin g of th e transi tion from the path to the street. If they fai l to detect guide for the development of bicycle facilities 71 the ramp, they are at risk of walking into the street, whic h may result in se ri ous conseq uences . If the ramp grade is low, a visua ll y impaired per- so n may not detect the transition . Detectable warnings and contrast in g co lo rs at the bottom of ramps m ay he lp detect the prese nce of a c urb ramp. A tradeoff may ex i st between the v i sua ll y impaired and mobility impaired when using truncated do med su rfaces , because m ane uve rabil - ity may be more difficult for both the bicyclist a nd the mobility im paired. Peop le w ith Limi ted Cog niti ve Abiliti es-We are learni ng that chi ldren under the age of 12 do not often think abo ut th e rules of the road (path), eve n when they have been taught. Their abi lity to take in a nd perceive the road env ironm ent, and then perform the multipl e tasks needed to make fast dec i sions , may not be developed. Planners and designers need to take into acco un t t he mi x in g of faste r movi ng modes with pedestrians when determining fac ility design , espec ia ll y if the path is a sc hoo l route . Adults with cognitive disabilities m ay benefit from easy-to-inte rpret signs . This may be partic ularl y important w hen a path intersects w ith an- other path o r street. Design Other Design Considerations guide for the development of bicycle facilities 73 Chapter 3 Operation and Maintenance The jurisdictions responsible for the operat ion, maintenance and polic- in g of bicycle facilities shou ld be estab li shed prior to construction. In addition to co nstruction costs, operati ng and maintenance costs shou l d be considered and included in the overa ll budget for the facility. Ne- glecting routine maintenance eventua ll y may render bicycle facilit ies unri dable and such deter ioratin g faci liti es may become a li abi l ity to the state or com muni ty. Bicyclists shou ld be enco uraged to report bicycle fa- c iliti es that are in need of maintena nce. A ce ntral contact person who ca n authorize m aintenance work shou ld be desi gnated to receive suc h reports. A smooth su rfa ce, free of potholes and debris, should be provided on all bikeways. Glass , sand, litter and fa ll en leaves often accum ul ate on bike lanes , paved shoulders and shared use paths; therefore , regular sweep in g is desirable . Pavement edges shou ld be uniform and shou ld not have abrupt drop-offs. Signs and pavement markings shou ld be inspected reg- ularl y and kept in good co nditi on, and if determined to be no longer necessary, promptly removed. Highways with bicycle traff i c may require a more frequent and higher leve l of maintenance th an other hi ghways. For shared use paths , attention should be given to maintainin g the full paved width and not all ow in g the edges to ravel. Trees , shrub s and other vegetation should be co ntroll ed to provide adequate cl ea rances and sight distances. Trash receptacles shou ld be placed and maintained at convenient locations. Seeded and sodded areas in the vic inity of share d use paths shou ld be mowed regular l y. Snow plowing sho uld be used to rem ove snow from bikeways because de-icing agents and abrasives ca n dam age bicycles. Also, enforcement is often necessary to prevent unau- thori zed motor vehicles from using a shared use path. The routine maintenance of roadways and bikeways will u suall y prov ide good riding co ndi tions. Several bicycle facility improveme nts described in thi s guide ca n be implemented during routine m aintenan ce activ iti es. Consideration also can be g iven to ad ju sting l ane widths and providing wider outside c ur b lanes for bicyclists during restriping operations. The addition of edge li nes can better delineate a shoulder, espec iall y at night. Wh en shou ld ers are resurfaced, a smooth surface su itable for bicycle rid- in g should be co nsid ered. Operation and Maintenance guide for the development of bicycle facilities 75 Appendix Review of Legal Status Bicycle programs must reflect applicable laws and ordinances. Bicycle facilities must not encourage or require bicyclists, pedestrians or motor- ists to operate in a manner inconsistent with the adopted Rules of the Road as described in Chapter 11 of the Uniform Vehicle Code (UVC). The National Committee on Uniform Traffic Laws and Ordinances, a group of more than 140 individuals involved in the complex problems of highway transportation , has developed and recommended the UVC as a comprehensive guide for state motor vehicle and traffic laws . In addi- tion , the provisions of the Model Traffic Ordinance (MTO) have been designed as a guide for municipalities to follow in considering the devel- opment or revision of their traffic ordinances. Since bicycles are defined as vehicles , familiarity with the provisions in the UVC and MTO is im- portant when developing bicycle facilities. The UVC and state and local laws and ordinances should be reviewed before decisions are made on thetypeoffacilitiesdesired . Sections 1-158, 11-201 , 11-313 , 11-1202 , 11-1205 , 11-1209, 11-1210, 11-1211and11-1213 of the UVC should be compared with corresponding state and municipal provisions . Appendix guide for the development of bicycle facilities 77 References 1 . A Po licy on Geometric D esig n of Hig h ways and St ree ts (G reen Book), Am eri ca n Association of State Hi ghway and Tr anspo rt ation Officia l s, 19 94. 2. Manua l of Uniform Tr affic Co ntro l Devices (MUTCD ), Fed era l Hi gh- way Adm ini stration , National Advisory Committee o n Uniform Traffic Control D ev ices, 1988. 3. Uniform Vehicle Co de (UVC), National Committee on Uni form Tr affic Laws and Ordinances, U .S. Government Print i ng Office, 199 2. 4 . Model Traffi c O rdinance (M TO ), Nation al Committee on Unifo rm Tr aff ic Laws and Ordinances , U .S. Government Printin g Office , 1992 . 5. Arizona Bicycle Facilities Planning and D es ig n Guidelines, Fac il it i es Plannin g Co mmittee of the Arizona Bicycle Task For ce , November 1988. 6. California High way D es ign Manual, Metric Editio n, California De- partm ent of Tran spo rtation , Jul y 1995 . 7. Oregon Bicycle Plan, Adopted by th e Oregon Tr anspo rtation Com- mi ss ion , Apr il 1995 . 8. Still More Bikes Behind th e Dikes, Centre for Resea rch and Contract Stand ard iza tion in Civi l and Traffic En gin ee r i ng, Th e Net herlands , Sep- temb er 1992 . 9. Bikeway Planning and Desig n, Cal ifornia Dep artm ent of Tr ans porta- tion, Jul y 1993. 10 . Sign Up for th e Bike: Desig n Manual for a Cycle-Friendl y Infrastruc- ture, Centre for Research and Contract Standardization in Civil and Traffi c Engineering, Th e Netherlands, August 199 3. 11. Selecting Ro adway Desig n Tr ea tm ents to Accommodate Bicycles (Pub l ication No. FHWA-RD-92 -073), Fed era l H ighway Admini stra tion, Januar y 199 4 . 12. Th e Effects of Bicycle Accommodations on Bicycle/Motor Vehicle Safety and Traffi c Operations (Publication No . FHWA -RD-92-0 69), Fed- eral Hi ghway Admini st ration , Jul y 1994 . 13. Conflicts on Multiple-Use Tr ails (Repo rt No . FHWA-PD-04-03 7), Fed eral Hi ghway Adm ini st ration , August 1994. Appendix 78 guide for the development of bicycle facilities Appendix 14. "Si gnal Clearance Timin g fo r the Bicyclist" by Alan Wachte l , John Forester and David Pelz , /TE Journal, March 1995, pp . 38-45. 15. Th e Deve lopment of Bi cycle Compatibi lity Ind ex: A Leve l of Service Co ncep t, Vo lum e 1 : Fin al Report (Pub l icat ion No. FHWA-RD-98 -072 ), Federal Hi ghway Administratio n, 1998.