HomeMy WebLinkAbout008 APPENDIX DTraffic Impact Study
9Ten Mixed Use
Bozeman, MT
8.10.2021
Project No: 21-05-32
1111 East Broadway, Missoula, MT 59802 I OFFICE 406.728.4611 I EMAIL wgm@wgmgroup.com
PTOE #4336
i 9Ten Mixed Use
Traffic Impact Study
REPORT DATE:
8.10.2021
AUTHOR:
Mark Bancale, P.E., PTOE
Senior Traffic Engineer
WGM Group, Inc.
ii 9Ten Mixed Use
Traffic Impact Study
CONTENTS
Introduction ............................................................................................................................... 1
Existing Traffic Volumes .......................................................................................................... 4
2023 No-Build Traffic Volumes ................................................................................................ 6
Nearby Roadway Improvement Projects ................................................................................. 8
Site-Generated Traffic ............................................................................................................ 10
Assignment of Site-Generated Trips ..................................................................................... 11
2023 Build Traffic Volumes .................................................................................................... 15
Capacity Analysis ................................................................................................................... 17
Summary, Conclusions, and Recommendations ................................................................. 20
APPENDIX A – Traffic Count Data
APPENDIX B – Capacity Analysis Worksheets
APPENDIX C – Level of Service Definitions
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Traffic Impact Study
INTRODUCTION
Good Housing Partnership proposes to construct the 9Ten mixed use development west of North 7th
Avenue between West Aspen Street and West Juniper Street in Bozeman, Montana (see Figure 1). The
proposed development will consist of two 4-story buildings containing 102 apartments and approximately
1,176 sf of commercial office space (see Figure 2). Full buildout of this mixed-use development is
expected to require two years. Accordingly, the design year for this traffic analysis is 2023.
Vehicle access to the development is proposed via West Aspen Street and West Juniper Street, two full-
movement roadways that connect to North 7th Avenue.
The subject property is currently undeveloped. It is surrounded by undeveloped agricultural land to the
west and commercial/industrial developments to the east.
This traffic impact study was prepared using standard traffic engineering techniques to forecast traffic
volumes and operations at the proposed site access points and nearby study intersections. Capacity
analysis is presented both with and without the traffic generated by the proposed development to
determine what impact, if any, this development will have on traffic operations. The City also asked that
the traffic analysis answer the question whether extension of North 8th Avenue from the development site
either north to West Oak Street or south to Durston Road is required to accommodate the traffic
generated by the proposed development.
After consultation with the City of Bozeman the following intersections were identified for detailed traffic
analysis:
1. West Juniper Street and North 7th Avenue
2. West Aspen Street and North 7th Avenue
In brief, the analysis conducted for this report leads to the conclusion that the subject development will
not negatively impact traffic operations at either of the study intersections and that traffic to and from
the proposed development will operate at an acceptable level of service. The extension of North 8th
Avenue to connect with either West Oak Street or Durston Road is not necessary to accommodate the
traffic generated by this development.
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FIGURE 2: CONCEPTUAL SITE LAYOUT
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EXISTING TRAFFIC VOLUMES
AM and PM peak-period manual traffic counts were conducted to identify existing traffic volumes at the
study intersections on Wednesday, July 14, 2021. The AM peak-period counts were conducted between
7:00 and 9:00 AM and the PM peak-period counts were conducted between 4:00 and 6:00 PM. The count
data (included in Appendix A) was analyzed to determine the existing AM and PM peak-hour traffic
volume at each study intersection. The existing peak-hour traffic volumes are illustrated in Figure 3.
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2023 NO-BUILD TRAFFIC VOLUMES
The year 2021 existing traffic volumes were projected to the study year 2023 using a 2% per year peak
hour traffic growth rate. This growth rate was selected based on traffic growth trends apparent within
historic traffic count data contained on the MDT web site along North 7th Avenue in the vicinity of the
subject property.
The 2023 No Build traffic volumes are shown in Figure 4. This is the traffic projected to exist in the study
year if the proposed 9Ten mixed use development is not constructed.
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NEARBY ROADWAY IMPROVEMENT
PROJECTS
NORTH 7TH AVENUE INTERSECTIONS IMPROVEMENTS
The North 7th Avenue Intersections Improvements project is a MDT project that’s purpose is to improve
all signalized intersections on North 7th Avenue from West Mendenhall Street to West Oak Street. The
intent is to adjust timing and phasing on intersecting streets to achieve more green time on North 7th
Avenue and to remove any split phasing on the side-street approaches. There will be no lane
configuration changes on North 7th Avenue itself; however, dual westbound left turn lanes will be added
on West Griffin Drive and a left turn lane will be added to the east leg of Peach Street. The east-west split
phase will be removed at the North 7th Avenue and Peach Street/Durston Road intersection and instead
east/west movements will run concurrently with a protected/permitted left turn phasing. These
improvements are expected to be constructed in 2023.
NORTH 7TH AVENUE AND GRIFFIN DRIVE
The North 7th Avenue and Griffin Drive intersection improvement project is currently scheduled to be
constructed in 2023. This project includes widening Griffin Drive and adding a left-turn lane to create dual
left-turn lanes heading south towards I-90, widening Mandeville Lane to provide a separated left-turn
lane, and widening North 7th Avenue to include three northbound and southbound lanes at the intersection
(one left-turn only, one through lane, and one right-turn only lane). The proposed intersection
improvements are illustrated in Figure 5.
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FIGURE 5: NORTH 7TH AVENUE AND GRIFFIN DRIVE PROPOSED LAYOUT
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SITE-GENERATED TRAFFIC
The proposed 9Ten mixed use development is anticipated to consist of 102 residential apartments, and
1,176 sf of commercial space. Data from the Institute of Transportation Engineers (ITE) publication Trip
Generation (10th Edition) was used to estimate the number of trips that will be generated by the proposed
development. Table 1 shows the results of the 9Ten development trip-generation calculations.
TABLE 1: 9TEN SITE-GENERATED VEHICLE TRIPS
Land Use Size
ITE Land
Use Code
Average
Daily Traffic
(ADT)
AM Peak-Hour Trips PM Peak-Hour Trips
Entering Exiting Entering Exiting
Apartments 102 Apts. 221 554 9 26 27 18
Commercial 1,176 SF 710 14 1 0 0 2
Total - - 568 10 26 27 20
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ASSIGNMENT OF SITE-GENERATED
TRIPS
The existing peak hour turning movement volumes at the study intersections were analyzed to
determine trip directionality throughout the study area. Trip distribution at the site access points was
estimated based on the distribution of the development within the site relative to the two site access
locations. The resulting site traffic arrival and departure patterns are illustrated in Figures 6 and 7,
respectively.
The site-generated vehicle trips from Table 1 were distributed through the study intersections in
accordance with the estimated arrival and departure patterns, resulting in the AM and PM peak-hour
site-generated trips shown in Figure 8. These are the vehicle trips that are new to the roadway
network as a result of development of the 9Ten mixed use development.
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2023 BUILD TRAFFIC VOLUMES
Combining the site-generated trips from Figure 8 with the 2023 no-build traffic volumes from Figure 4
results in the projected study year 2023 build traffic volumes shown in Figure 9. These are the traffic
volumes projected to exist when the 9Ten mixed use development is fully built-out and occupied.
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CAPACITY ANALYSIS
Intersection capacity analysis was conducted for each of the study intersections in accordance with the
procedures presented in the Highway Capacity Manual, 2016 Edition, published by the Transportation
Research Board. The analysis results are discussed below and the analysis worksheets are contained
in Appendix B.
The analysis procedures result in traffic level of service (LOS) rankings from A to F, with A representing
essentially free-flow conditions and F representing congested conditions. See Appendix C for a
description of the various LOS categories for unsignalized intersections.
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INTERSECTION OF WEST JUNIPER STREET AND
NORTH 7TH AVENUE
EXISTING CONDITIONS
North 7th Avenue is a north/south principal arterial with two travel lanes in each direction and a
center two-way left-turn lane. West Juniper Street is an east/west local roadway. West Juniper
Street intersects North 7th Avenue from the west at a full movement, stop controlled, “T”
intersection. The speed limit on North 7th Avenue is 35 mph and the speed limit on West Juniper
Street is not posted, a speed limit of 25 mph was assumed.
CAPACITY ANALYSIS
Capacity analysis of this intersection was conducted using the 2023 no-build and build traffic
volumes developed earlier in this report and the above-described intersection configuration. The
analysis was performed using a Synchro traffic model in order to take into account the traffic
signal progression on North 7th Avenue and the surrounding signalized intersection’s impacts to
capacity at this unsignalized intersection. The results of this analysis are summarized in Table 2.
TABLE 2: NORTH 7TH AVENUE AND WEST JUNIPER STREET LOS SUMMARY
Peak AM Hour Peak PM Hour
2023 No-Build 2023 Build 2023 No-Build 2023 Build
Delay LOS Delay LOS Delay LOS Delay LOS
Eastbound 21.8 C 18.5 C 18.4 C 20.0 C
Westbound 13.4 B 13.5 B 16.8 C 16.9 C
Delay is measured in seconds per vehicle.
The analysis summarized in Table 2 shows that the site-generated traffic will have no appreciable
impact on delay or operations at this intersection. No intersection improvements are required.
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INTERSECTION OF WEST ASPEN STREET AND NORTH
7TH AVENUE
EXISTING CONDITIONS
North 7th Avenue is a north/south principal arterial with two travel lanes in each direction and a
center two-way left-turn lane. West Aspen Street is an east/west local roadway. West Aspen
Street intersects North 7th Avenue from the west at a full movement, stop controlled, “T”
intersection. The speed limit on North 7th Avenue is 35 mph and the speed limit on West Aspen
Street is not posted, a speed limit of 25 mph was assumed.
CAPACITY ANALYSIS
Capacity analysis of this intersection was conducted using the 2023 no-build and build traffic
volumes developed earlier in this report and the above-described intersection configuration. The
analysis was performed using a Synchro traffic model in order to take into account the traffic
signal progression on North 7th Avenue and the surrounding signalized intersection’s impacts to
capacity at this unsignalized intersection. The results of this analysis are summarized in Table 3.
TABLE 3: NORTH 7TH AVENUE AND WEST ASPEN STREET LOS SUMMARY
Peak AM Hour Peak PM Hour
2023 No-Build 2023 Build 2023 No-Build 2023 Build
Delay LOS Delay LOS Delay LOS Delay LOS
Eastbound 25.1 D 19.6 C 40.9 E 48.4 E
Westbound 12.3 B 12.4 B 22.9 C 24.1 C
Delay is measured in seconds per vehicle.
The analysis summarized in Table 3 shows that the site-generated traffic will have no impact on
delay or operations at this intersection. No intersection improvements are required.
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SUMMARY, CONCLUSIONS, AND
RECOMMENDATIONS
The discussion and analyses contained in this report can be summarized as follows:
The proposed 9Ten mixed use development is on North 7th Avenue between West Aspen Street
and West Juniper Street in Bozeman, Montana. The proposed development will consist of two 4-
story buildings with 102 apartments and approximately 1,176 sf of commercial office space.
Vehicle access to the development is proposed via West Aspen Street and West Juniper Street,
two full-movement roadways that connect to North 7th Avenue.
The proposed development will generate new traffic within the study area; however, the new site-
generated volumes will be relatively minor, in the range of only 35 to 50 total vehicles per peak
hour.
Synchro model based analysis shows that the site-generated traffic can be readily
accommodated, with no appreciable impact on delay or operations at either of the study
intersections during the AM and PM peak hours.
Extension of North 8th Avenue from the subject site to connect with either West Oak Street or
Durston Road is not necessary to accommodate this development.
9Ten Mixed Use
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APPENDIX A
TRAFFIC COUNT DATA
Manual Traffic Count
N 7th Ave & Aspen
Bozeman, MT
Wednesday, July 14, 2021
Peak AM Period
Interval Hourly
Right Thru Left Right Thru Left Right Thru Left Right Thru Left Total Total
7:00 AM 7:15 AM 1 82 3 0 0 0 1 78 2 0 0 0 167
7:15 AM 7:30 AM 1 143 8 0 0 0 2 95 2 0 0 0 251
7:30 AM 7:45 AM 1 153 4 0 0 0 3 100 5 0 0 0 266
7:45 AM 8:00 AM 0 183 2 1 0 1 1 108 3 0 0 4 303 987
8:00 AM 8:15 AM 1 116 2 1 0 1 1 99 4 0 0 1 226 1046
8:15 AM 8:30 AM 2 193 2 1 0 0 0 130 3 0 0 0 331 1126
8:30 AM 8:45 AM 1 162 2 1 0 0 0 173 6 0 0 1 346 1206
8:45 AM 9:00 AM 0 187 5 2 0 0 3 142 5 0 0 1 345 1248 <-- Peak Hour
Peak Hour 4 658 11 5 0 1 4 544 18 0 0 3
Volume
PHF =0.9
Wednesday, July 14, 2021
Peak PM Period
Interval Hourly
Right Thru Left Right Thru Left Right Thru Left Right Thru Left Total Total
4:00 PM 4:15 PM 2 181 4 4 0 0 1 266 13 0 0 4 475
4:15 PM 4:30 PM 1 165 6 5 0 0 2 259 5 2 1 1 447
4:30 PM 4:45 PM 1 188 3 2 0 1 1 238 7 1 1 3 446
4:45 PM 5:00 PM 3 196 4 3 0 1 0 213 4 1 0 3 428 1796
5:00 PM 5:15 PM 3 229 3 7 0 0 4 265 14 1 0 2 528 1849
5:15 PM 5:30 PM 1 243 4 10 0 3 2 238 13 4 0 3 521 1923
5:30 PM 5:45 PM 1 198 3 5 0 2 3 235 15 1 0 1 464 1941 <-- Peak Hour
5:45 PM 6:00 PM 5 166 3 1 0 0 1 189 8 0 0 2 375 1888
Peak Hour 8 866 14 25 0 6 9 951 46 7 0 9
Volume
PHF =0.92
Southbound Northbound Eastbound
Southbound Northbound Eastbound
Westbound
Westbound
4*15V
VPHF
Manual Traffic Count
N 7th Ave & Juniper
Bozeman, MT
Wednesday, July 14, 2021
Peak AM Period
Interval Hourly
Right Thru Left Right Thru Left Right Thru Left Right Thru Left Total Total
7:00 AM 7:15 AM 0 96 5 10 0 0 1 74 0 0 0 1 187
7:15 AM 7:30 AM 1 141 9 6 0 4 1 103 0 0 0 1 266
7:30 AM 7:45 AM 1 182 10 7 0 1 3 96 1 2 0 0 303
7:45 AM 8:00 AM 0 191 16 10 0 0 4 121 4 0 0 3 349 1105
8:00 AM 8:15 AM 1 158 11 10 0 1 6 106 2 0 0 0 295 1213
8:15 AM 8:30 AM 4 188 8 6 0 0 1 129 2 0 0 0 338 1285
8:30 AM 8:45 AM 7 187 13 7 1 1 4 159 2 1 0 0 382 1364
8:45 AM 9:00 AM 3 201 18 7 0 2 6 156 4 0 0 1 398 1413 <-- Peak Hour
Peak Hour 15 734 50 30 1 4 17 550 10 1 0 1
Volume
PHF =0.89
Wednesday, July 14, 2021
Peak PM Period
Interval Hourly
Right Thru Left Right Thru Left Right Thru Left Right Thru Left Total Total
4:00 PM 4:15 PM 3 213 3 13 0 2 3 249 4 6 0 0 496
4:15 PM 4:30 PM 0 175 8 9 0 1 1 270 4 1 0 0 469
4:30 PM 4:45 PM 0 184 3 9 0 3 6 245 1 3 0 0 454
4:45 PM 5:00 PM 3 196 4 12 0 1 9 220 3 2 0 0 450 1869
5:00 PM 5:15 PM 2 248 4 23 0 0 6 270 1 3 0 3 560 1933
5:15 PM 5:30 PM 0 232 6 12 0 3 5 247 1 6 0 0 512 1976
5:30 PM 5:45 PM 0 205 7 15 0 0 1 246 0 7 0 0 481 2003 <-- Peak Hour
5:45 PM 6:00 PM 1 180 7 7 0 0 2 205 0 1 0 2 405 1958
Peak Hour 5 881 21 62 0 4 21 983 5 18 0 3
Volume
PHF =0.89
Southbound Northbound Eastbound
Southbound Northbound Eastbound
Westbound
Westbound
4*15V
VPHF
9Ten Mixed Use
Traffic Impact Study
APPENDIX B
CAPACITY ANALYSIS WORKSHEETS
9Ten Mixed Use
Traffic Impact Study
APPENDIX C
LEVEL OF SERVICE DEFINITIONS
9Ten Mixed Use
Traffic Impact Study
UNSIGNALIZED INTERSECTION LEVEL OF SERVICE
DEFINED
Level of Service (LOS) for unsignalized (two-way-stop-controlled) intersections is determined by the
control delay experienced by drivers on each minor approach. Minor movements are those entering from
or exiting onto the stop-controlled side street(s). LOS is not defined for the intersection as a whole, but
rather for each minor movement individually.
The delay value used in determining LOS is known as “control delay.” Control delay is defined as the
total delay experienced by a driver and includes initial deceleration delay, queue move-up time, stopped
delay, and final acceleration delay. The delay a vehicle experiences is a function of the capacity of the
approach and the degree of saturation on the uncontrolled (unstopped) roadway (i.e. the number of
acceptable gaps in the passing traffic stream).
LOS values range from A to F. The delay range for each LOS value is as shown in the following table.
LOS CRITERIA FOR TWO-WAY STOP-CONTROLLED INTERSECTIONS
LOS AVERAGE CONTROL DELAY (SECONDS/VEHICLE)
A 0-10
B >10-15
C >15-25
D >25-35
E >35-50
F >50
Source: Transportation Research Board, Highway Capacity Manual, HCM2010