HomeMy WebLinkAboutTIA APR-J0 - 03 THU 9:05 AM U UE STRATEGIES FAX N0, 5127958431 P,
JEFF MILBURN ENGI EERI
Jeffrey T. Milburn, P.E.
P.O. Box 10240, College Station, Texas 77842
Phone 979- 690 -2560 Fax 979 - 690 -2540
September 4, 2002
Mr. Dan Bensimon
5810 Toin Wooten
Austin, Texas 78731
Re: Autumn Chase Subdivision Traffic Impact Assessment
Dear Mr. Bensimon:
Please accept this letter report of analysis and findings on the referenced project. I have
completed this traffic impact assessment to answer some questions regarding issues related to
Cornell Street as it runs through this subdivision. I have discussed the matter with Mr. Ken
Fogle with the City of College Station and Mr. Kirk Barnes with TxDOT to obtain background
information and areas of concern.
introduction
Principal issues that are of interest to this project and that have been investigated and discussed
below are as follows:
1. What are the projected traffic patterns in the area of this subdivision?
2. What are the expected traffic volumes for Cornell in this area?
3. What is the functional classification of Cornell?
4. How does function of Cornell influence the design parameters for the street?
5. How will future improvements affect the function of Cornell?
6. What is the recommended right-of-way width and street width for the functional
requirements of Cornell?
7. Will the presence of driveways on Cornell impair its function?
This study is based on several items of data including zoning information and usi rent development
maps, both of which were provided by the City of College Station. Development data for the subject
tract was provided by SI Group LP. Data on the apartment tract considered was provided by the
Ridge Apartments management staff All assistance in providing data is greatly appreciated.
$ITE AND PROJECT DESCRIPTION
The tract for the proposed project is approximately 8.35 acres of undeveloped land in a largely
developed area in the midst of College Station. The tract of land is bisected by a proposed section
of Comell Drive which currently terminates on cite= side of the tract. It is this missing link of
Cornell Drive which involves in large measure the questions related above. Mixed development
Civil Engineering Transportation Engineering Accident Reconstruction
APR:10 -03 THU 9:06 AM U ' STRATEGIES FAX H. X127956431 P. 3
Autumn Chase Subdivision
Traffic Impact Assessment Report
exists in the area and predates much of the land use planning efforts of the City of College Station.
The attached Area Map shows much of the existing development and street layout as well as the
proposed tract and several tract definitions used in this report. The area of study for this report is
bounded on the north by Harvey Road; on the east by Dartmouth Drive; on the south by Southwest
Parkway; and on the west by Texas Avenue. The influences of the proposed development are
unlikely to be felt outside this area.
EXISTING AND FUTURE TRAFFIC CONDITIONS
Existing Traffic Conditions
No traffic counts were made for this study since Cornell Drive dead ends adjacent to the tract on both
sides, however, projections of traffic volumes have been made based on existing and future
development. Generally trip generation is calculated for existing and projected development. For
this report the trip generation data contained in the ITE publication on Trip Generation, 6 Edition,
1997 has been utilized. This document is used throughout the United States for these purposes and
is basically a compendium of data from traffic studies that yield trip generation rates for various
standard development definitions and sizes. The data is not precise but can be used as a general
guidc to determine the number of vehicles per hour or day that a particular development would be
expected to contribute to the load on the transportation system.
As always, traffic projections are based on certain assumptions. In this case certain areas of
development are expected to contribute to traffic on Cornell Drive and these are included in this
analysis. These areas are those shown on the Area Map and generally are adjacent to Cornell,
Manuel, Richard and Sterling. The tract sizes, uses and trip generation figures are presented in
Table 1 for average daily traffic (ADT) and for peak hour volumes. These figures represent the total
generation of trip ends for the given tract of land, however, directional splits must be considered to
determine how much of the traffic actually will travel on Cornell Drive. This analysis is presented
later in this report. Zoning information for this area is attached for reference for land use data.
Existing and Future Roadway System
The City of College Station has developed a Major Thoroughfare Plan for identifying its major
roadways. A portion of this plan which represents the study area is included as attached. The Area
Map shows that Cornell does not presently connect Brentwood to Manuel as shown on the
Thoroughfare Plan. That connection is to be made during this project. On the northern boundary
of the study area Lassie Street aligns approximately with Cornell, however Lassie and Cornell are
not connected in this area because of an existing residence south of Sterling and an existing 4-plex
north of Manuel. For this connection to be made these residences would have to be purchased and
demolished. Lassie is currently a 28 ft. in width (B -B) roadway and has some angled parking at the
Verizon tract near Holleman Drive. The existing portions of Cornell are constrµcted at 39 ft. (B -
south of the proposed tract and 28 ft. (B - B) adjacent to Manuel. The wider sections identified are
in conformance with City requirements for a minor collector street.
Future changes in the area will have some effects on the travel patterns in the area of the subject
tract. Future improvements to Texas Avenue will provide a raised curbed median which will limit
APR - 10 - 03 THU 9:07 AM U'' UE STRATEGIES FAX NO. 5127958431 P. 4
Autumn Chase Subdivision
Traffic Impact Assessment Report
certain turning movements except at major intersections. Median breaks are planned for the
intersections at Southwest Parkway, Brentwood, Manuel, Holleman Drive and Harvey Road. Each
of these intersections is or will be signalized as well. No other traffic signals or major roadway
improvements are known to be planned at this time.
Traffic Patterns
Existing traffic patterns are nominally in conformance with the intent of the Major Thoroughfare
Plan. The heaviest volumes and longest trips are made on major and minor arterials. Major arterials
in this area are Texas Avenue and the SH 6 By -Pass running north and south, with Harvey Road
running east and west. Minor arterials include Dartmouth running north and south, with Holleman
Drive and Southwest Parkway running east and west. For the most part trips generated in or near
the subject tract will be heading toward these streets. It is noteworthy that there are no major single
traffic generators within the study area. The Ridge Apartments complex just east of the subject tract
is probably the single greatest generator and it is not a very dense area having only 192 units (a total
01 328 bedrooms, most occupied by single students) on a tract of some 13.6 acres. Currently this site
fronts on Dartmouth and has driveway access only to that minor arterial. Construction of Cornell
will allow "back door" access from this apartment complex and will provide, if the owner chooses
to allow it, a pathway to the northwest and southwest via Cornell and either Manuel or
Brentwood/Southwest Parkway respectively. No other changes in traffic patterns are anticipated
unless the connection of Lassie to Cornell is made in the future, the effects of which are discussed
below.
An analysis of traffic patterns after the connection of Cornell to Manuel must be done to estimate
the percentage drivers which will choose a particular travel path. For example, a driver who wishes
to travel from the subject tract must travel on Cornell Drive since there is no other outlet path and
may go north or south. A driver on Manuel Drive near its intersection with Cornell, however, has
several options. If the driver wishes to travel southeast toward south College Station, they may
travel south on Cornell to Brentwood, to Dartmouth and then to the signalized intersection for a left
turn onto Southwest Parkway. It is unlikely that they will travel to Cornell at Southwest Parkway
to turn left since there is no signal there, however at offpeak hours this path is reasonable. It is also
possible that this same person will travel on Manuel to Texas Avenue then south. Some percentage
of the driving populace will choose a particular path and these percentages have been estimated in
assigning directional splits to the traffic generated by the various tracts identified in Table 1.
Assessment of these percentage directional assignments has been made in Tables 2 -5 attached.
Directional assignment is perhaps the most subjective part of a traffic impact assessment and is based
on the writer's familiarity with local traffic patterns and driver behavior. The percentages may vary
significantly with time of year or with time of day, however, the data presented in these tables is
deemed to be reasonable as an estimate. Basic assumptions are that a majority of traffic from the
subject area, since it is primarily students, will be headed toward Texas A&M University via Texas
Avenue. This is assigned a northwest direction. Some traffic will also travel southeast or southwest
toward other business and shopping areas. It is anticipated that a significant percentage will travel
to the northeast toward the Post Oak Mall and the restaurants and shopping areas around it. Based
on the estimates of these percentages a further breakdown of directional assignment is made from
each area identified in Table 1, called contributing areas, each of which is assigned a percentage
using Cornell Drive. These trips are then added to provide a basic estimate of traffic volume on
APR - U3 '1'HU 9:U8 AM Ur"'Ul; STRATEGIES FAX NO, `11'27958431 F. 5
Autumn Chase Subdivision
Traffic Impact Assessment Report
Cornell Drive, It is believed that the estimates are conservative (high) and represent a fair
assessment of maximum future volumes on Cornell Drive.
Tables 2 and 3 include values for no future connection of Lassie to Cornell. Tables 4 and 5 include
this connection and assume that some southbound traffic from the areas of Richards and Sterling
Streets adjacent to Lassie may use Cornell, although the percentages are small given that Dartmouth,
Texas Avenue, Harvey Road and SH 6 are relatively close and provide shorter travel times generally.
The signalization of the Manuel/Texas intersection, which is soon to be under construction, will
reduce the need for this connection.
Functional Classification
Much of the consideration in this assessment is focused on the Major Thoroughfare Plan and the
roadway classification of Cornell Drive. Generally roadways are divided into three main functional
classifications, arterial, collector and local streets, based on what function they perform in the
meeting of travel demand. Functional classification is not dependent on traffic volume, at least in
theory, however traffic volume does generally depend on roadway functional classification. One
of the primary differences in the classifications is how access is handled. Generally when greater
movement function is needed, ease of access must decrease. This relationship is graphically
portrayed in the access mobility curve below.
FUNCTIONAL
FUNCTION CLASS
ARTERIAL
M ovement
COLLECTOR
Accts* LOCAL
Functional Classification Based on Movement
and Land Access
Arterial streets provide the highest degree of mobility and normally see the highest traffic volumes.
These are desirably spaced at 1 -2 mile intervals in both north & south and east & west directions.
APR .10 - 03 THU 9:09 AM Ur 'UE STRATEGIES FAX NO. 127958431 P. 6
Autumn Chase Subdivision
Traffic Impact Assessment Report
Arterials maybe subdivided into major and minor classifications and generally the spacing retreats
to I A mile intervals. Arterials provide for more movement by restricting access. Both providing
median restrictions and enforcing driveway spacing requirements accomplish this important principle
on arterial street.
Collector streets are included in the middle ofthe curve shown, attempting to provide both functions,
movement and access. In providing both functions they also compromise both functions.
Collectors are also subdivided into major and minor classifications with additional pavement and
right -of -way widths being provided on Major Collectors. A collector functions normally to provide
the movement of traffic to adjacent arterial streets with reasonably shore trip lengths. Cornell does
in fact serve this function carrying traffic to Southwest Parkway on the south and to a lesser extent
northward. The Major Thoroughfare Plan shows Cornell connecting to Holleman on the north, but
not Harvey Road. A connection to Harvey Road might promote cut - through traffib, such as that seen
on Munson Avenue to the south. The Munson problem is produced by the connection to Dartmouth
at Harvey Road and the lack of a north -south arterial street between SH 6 and Texas avenue north
of Harvey Road. That situation is very different from the Cornell drive issue because Dartmouth
provides this functional need in this area.
One of the primary questions in this area of study is whether or not a major collector is needed at the
Comell/Lassie location to provide for north/south mobility. Two primary factors govern this
decision being: 1) the existing spacing of collector and arterial streets, and 2) the land use density
in the area. Currently Dartmouth and Texas Avenue are spaced at about 3500 feet apart at Holleman,
and about 2350 feet apart at Southwest Parkway. These spacings are consistent with the need for
a collector street in the Cornell Drive location. The land use densities, however, are relatively
diffuse in the subject area. The residential character of the core area of the study location provides
less dense development and the resulting lower traffic volumes. Good east -west mbbility is provided
by Manuel and Brentwood, both having signalized access to Texas Avenue. Anticipated traffic
volumes on Cornell show around 1000 vehicles per day (VPD) and about 130 vehicles per hour
(VPH) for the peak hour, about 2 vehicles per minute. Neither value is unreasonable for a minor
collector roadway and both are conservative (probably high) estimates of traffic volume.
Additional Considerations
Three additional considerations require discussion herein. First, the existing construction along
Cornell/Lassie is for a minor collector street, or less, in terms of right -of -way width and pavement
width. If the section of Cornell within the subject tract is built with the cross section of a major
collector, awkward transitions will be required on either end to the existing pavement widths.
Second, the connection of Cornell to Lassie would involve the removal of two existing structures
and will provide the possibility, however, unappealing, for cut - through traffic from Holleman to
Southwest Parkway.
A third consideration is whether ur rout to a11uw diivcway awess duotly to Cornotl Drive in the area
of the Autumn Chase Subdivision. Allowing driveway access to a collector streets is currently
discouraged by City requirements. Currently there are seven homes with direct driveway access to
Cornell in the block just south of the Autumn Chase Subdivision location. Even with the prospect
of increased volume on Cornell from the subject development and connection to the apartment
complex shown, the traffic volumes presented should provide no problems for direct driveway access
APR - j0 - 03 THU 9 :09 AM U 1 1UE STRATEGIES FAX NO, 51 7958431 P, 7
Autumn Chase Subdivision
Traffic Impact Assessment Report
at the Autumn Chase location. Sight distances are good and trip lengths arc short, and therefore
speeds should be low. Allowing driveway access ut this location should not present significant
problems.
The effects of driveway access may be mitigated by using good driveway design for the duplex units
whereby both units have maneuvering room within the driveway to provide head out access to
Cornell Drive. Backing out of driveways would increase the exposure time for each driveway exit
maneuver and reduce the capacity and increase the congestion on Cornell Drive.
CONCLUSIONS AND RECOMMENDATIONS
These conclusions and recommendations are based on reasonable engineering analysis and represent
the results of an adequate study on the subject area. It is important to realize that the
recommendations made herein do not t:unsider public policy issues such as setting of precedent.
1. The construction of Cornell Drive within the sUbj ect Autumn Chase development as a minor
collector street is consistent with the present and predictable future needs for traffic.
Pavement widths and right -of -way widths for a minor collector should function very well for
this roadway.
2. Based on roadway spacing and density of land d evelopment as outlined above no north -south
major collector will be needed between Dartiiiouth and Texas Avenue in the area between
Holleman Drive and Southwest Parkway.
3. The revision of the Major Thoroughfare Plat to reflect this greater understanding of need is
appropriate.
4. The connection of Lassie to Cornell is not highly recommended as it is unnecessary and may
promote cut- through traffic.
5. Driveway access to Cornell Drive within the Autumn Chase Subdivision may reasonably be
allowed without producing significant congestion or a significant reduction in safety.
Driveways should be designed for head out maneuvers.
If you have questions regarding this information or require additional information please
contact me at the above address of telephone number. I will provide two copies of this letter report
to Mr. Fogle with the City of College Station at your direction.
Sincerely,
Jeffrey T. Milburn, P.E.
President
APR - 18 - 03 THU 9:10 AM U" STRATEGIES FAX NO. 5127958431 P. 8
Autumn Chase Trip Generation Table 1
Area Land Use Size Unit Generation Rate Trip Ends
Average Daily Traffic
1 Subject Tract 86 Units 8.0 VPD /Unit 688
2 5.22 Acre PUD ( :192 Units) 96 Units 8.0 VPD /ynit 768
3 Manuel 4-Piexes 68 Units 8.0 VPD /Unit 544
4 Manuel Minl- Storage 3.90 Are 39.0 VPD /Ac 152
5 Manuel Commercial Tract 8,000 SF 41.0 VPD /KSF 328
(Specialty Retail part of larger tract)
(0.80 acres a 10000 sf /acre)
6 Richards & Sterling Street R1 104 Units 8.0 VPD /Unit 832
Evening Peak Hour]
1 Subject Tract 86 Units 1.0 VPH/Unit 86
2 5.22 Acre PUD ('/ :192 Units) 96 Units 1.0 VPH /Unit 96
3 Manuel4 - Piexes 68 Units 1.0 VPH /Unit 68
4 Manuel Mini - Storage 3.90 Acre 4.0 VPH /Ac 16
5 Manuel Commercial Tract 8,000 SF 2.6 VPH/KSF 21
(Specialty Retail part of larger tract)
(0.80 acres 0 10000 sflacre)
6 Richards & Sterling Street R1 104 Units 1.0 VPD /Unit 104
APR - 10 - 03 THU 9:11 AM U "'1UE STRATEGIES FAX NO, 5127958431 P. 9
Autumn Chase ADT Directional SOlit Table 2
FOR NO CONNECTION TO LASSIE
Direction of Travel
Percentage of Traffic
20% Headed Southeast ADT ADT Using Cornell
VPH VPH
Percentage Using Cornell Contributor
100% 1 Subject Tract 688 138
20% 2 PUD tract (5.22 ac.) 768 31
60% 3 Manuel 4-Plexes 544 65
60% 4 Manuel Mini Storage 152 18
50% 5 Manuel Commercial 328 33
20% Headed Southwest ADT ADT Using Cornell
VPH VPH
Percentage Using Cornell Contributor
100% 1 Subject Tract 60 138
25% 2 PUD tract (5.22 ac.) 768 38
40% 3 Manuel 4-Plexes 544 44
40% 4 Manuel Minl Storage 152 12
20% 5 Manuel Commercial 328 13
20% Headed Northeast ADT ADT Using Cornell
VPH VPH
Percentage Using Cornell Contributor
100% 1 Subject Tract 688 138
30% 2 PUD tract (5.22 ac.) 768 46
0% 3 Manuel4 - Plexes 544 0
0% 4 Manuel Mini Storage 152 0
0% 5 Manuel Commercial 328 0
40% Headed Northwest ADT ADT Using Cornell
VPH VPH
Percentage Using Cornell Contributor
100% 1 Subject Tract 688 275
25% 2 PUD tract (5.22 ac.) 768 77
0% 3 Manuel 4-Plexes 544 0
0% 4 Manuel Mini Storage 152 0
0% 5 Manuel Commercial 328 0
100% Total VPD 1065
APR - 03 THU 9:11 AM U' "IUE STRATEGIES FAX NO, 5127958431 P,10
Autumn Chase Peak Hour Directional Split
FOR NO CONNEC TO LASSIE Table 3
Direction of Travel
Percentage of Traffic
20% Headed Southeast PH Vol PH Using Cornell
VPH VPH
Percentage Using Cornell Contributor
100% 1 Subject Tract 86 17
20% 2 PUD tract (5.22 ac.) 96 4
60% 3 Manuel 4-Plexes 68 8
60% 4 Manuel Mini Storage 16 2
50% 5 Manuel Commercial 21 2
20% Headed Southwest PH Vol PH Using Cornell
VPH VPH
Percentage Using Cornell Contributor
100% 1 Subject Tract 86 17
25% 2 PUD tract (5.22 ac.) 96 5
40% 3 Manuel 4-Plexes 68 5
40% 4 Manuel Mini Storage 16 1
20% 5 Manuel Commercial 21 1
20% Headed Northeast PH Vol PH Using Cornell
VPH VPH
Percentage Using Cornell Contributor
100% 1 Subject Tract 86 17
30% 2 PUD tract (5.22 ac.) 96 6
0% 3 Manuel 4-Plexes 68 0
0% 4 Manuel Mini Storage 10 0
0% 5 Manuel Commercial 21 0
40% Headed Northwest PH Vol PH Using Cornell
VPH VPH
Percentage Using Cornell Contributor
1p0% 1 Subject Tract 86 34
25% 2 PUD tract (5.22 ac.) 96 10
0% 3 Manuel 4-Plexes 68 0
0% 4 Manuel Mini Storage 16 0
0% 5 Manuel Commercial 21 0
100% Total VPH 130
APR - 10 - 03 THU 9:1' AM U' "'lUE STRATEGIES FAX NO. 5127958431 P. 11
Autumn Chase Peak Hour Directional `
Split
INCLUDING CONNECTION TO LASSIE Table 5
Direction of Travel
Percentage of Traffic
20% Headed Southeast PH Vol PH Uslpg Cornell
Percentage Using Cornell Contributor VPH VPH
100% 1 Subject Tract 86 17
20% 2 PUD tract (5.22 ac.) 96 4
60% 3 Manuel 4-Plexes 68 8
60% 4 Manuel Mini Storage 16 2
50% 5 Manuel Commercial 21 2
40% 6 Richards & Sterling R1 104 8
20% Headed Southwest PH Vol PH Wang Cornell
VPH VPH
Percentage Using Cornell Contributor
100% 1 Subject Tract 86 17
25% 2 PUD tract (5.22 ac.) 96 5
40% 3 Manuel 4-Plexes 68 5
40% 4 Manuel Mini Storage 16 1
20% 5 Manuel Commercial 21 1
20% 6 Richards & Sterling R1 104 4
20% Headed Northeast PH Vol PH Using Cornell
VPH VPH
Percentage Using Cornell Contributor
100% 1 Subject Tract 86 17
30% 2 PUD tract (522 ac.) 96 6
0% 3 Manuel 4-Plexes 68 0
096 4 Manuel Mini Storage 16 0
0 % 5 Manuel Commercial 21 0
40% Headed Northwest PH Vol PH Using Cornell
VPH VPH
Percentage Using Cornell Contributor
100% 1 Subject Tract 86 34
25% 2 PUD tract (5.22 ac.) 96 10
0% 3 Manuel 4-Plexes 68 0
0% 4 Manuel Mini Storage 16 0
0% 5 Manuel Commercial 21 0
100% Total VPH 142
APR.-1,0-03 THU 9:1° AM UST' UE STRATEGIES FAX NO. 9 127958431 P.12
Autumn Chase ADT Directional Split Table 4 t
INCLUDING CONNECTION TO LASSIE
Direction of Travel
Percentage of Traffic
20% Headed Southeast ADT ADT Using Cornell
VPH VPH
Percentage Using Cornell Contributor
100% 1 Subject Tract ; 688 138
20% 2 PUD tract (6.22 ac.) 768 31
60% 3 Manuel 4-Plexes 544 65
60% 4 Manuel Mini Storage 152 18
50% 5 Manuel Commercial 328 33
40% 6 Richards & Sterling R1 832 67
20% Headed Southwest ADT ADT Using Cornell
VPH VPH
Percentage Using Cornell Contributor
100% 1 subject Tract 688 138
25% 2 PUD tract (5.22 ac.) 768 38
40% 3 Manuel 4-Plexes 544 44
40% 4 Manuel Mini Storage 152 12
20% 5 Manuel Commercial 328 13
20% 6 Richards & Sterling R1 832 33
20% Headed Northeast ADT ADT Using Cornell
VPH VPH
Percentage Using Cornell Contributor
100% 1 Subject Tract 688 138
30% 2 PUD tract (5.22 ac.) 788 46
0% 3 Manuel 4-Plexes 544 0
0% 4 Manuel Mini Storage 152 0
0% 5 Manuel Commercial 328 0
40% Headed Northwest ADT ADT Using Cornell
VPH VPH
Percentage Using Cornell Contributor
100% 1 Subject Tract 688 275
25% 2 PUD tract (5.22 ac.) 768 77
0% 3 Manuel4 - Plexes 544 0
0% 4 Manuel Mini Storage 152 0
0% 5 Manuel Commercial 328 0
100% Total VPD 1165