HomeMy WebLinkAbout026 TIS Addendum November 2024
130 South Howie Street
Helena, Montana 59601
406-459-1443
November 22, 2024
Josh Wolfram
WWC Engineering
895 Technology Blvd, Ste 203
Bozeman, MT 59718
RE: Blackwood Groves TIS Addendum
Dear Josh,
It is my understanding that the City of Bozeman has requested additional traffic
information for the planned development of Blocks 1 and 13 along South 19th Avenue
within the Blackwood Groves development. The City has requested a review of the
possible traffic impacts from the development of 216 new residential apartments on the
property. While the original traffic analysis for the Blackwood Groves development
prepared by ATS did not include specific land uses for these lots, the November 2021
addendum to the TIS analyzed the specific impacts of developing 204 additional residential
apartments on Blocks 1 and 13 in Phase 2 of the project (previously planned for Phase 9).
The November 2021 addendum suggested that the proposed apartments would increase
delay at the study intersections, but the LOS will remain within acceptable levels.
ATS performed a new trip generation analysis to determine the future traffic impacts from
the proposed development using the trip generation rates contained in Trip Generation
(Institute of Transportation Engineers, Eleventh Edition) for the full Blackwood Groves
development. The latest edition of the trip generation manual contains slightly lower rates
for the proposed land uses within the development compared to the previous Tenth Edition.
According to the new ITE trip generation rates, at full build-out the development would
produce 840 AM peak hour trips, 1,334 PM peak hour trips, and 14,234 daily trips. The
total trip generation using the latest trip generation rates is slightly lower (-4.2%) than the
values calculated for the previous addendum even with the higher number of units (216
units vs 204 units) on Blocks 1 and 13. See Table 1 for current detailed trip generation
information. With the lower trip generation rates, the specific traffic generation for Blocks
1 and 13 is also slightly lower than the previous estimates (1,109 daily trips previous vs
981 daily trips current). The specific trip generation rates for the current development
plans on Blocks 1 and 13 are shown in Table 2.
Based on the proximity to MSU and the high number of pedestrians observed in this area,
it is likely that many of the residents of the apartments will be MSU students and many
will walk or bike to MSU. However, no reduction was made for the likely pedestrian trips
to provide a more conservative analysis of the roadway impacts in this area.
2
Table 1 – Full Buildout Trip Generation Rates
Land Use
Units
AM Peak
Hour Trip
Ends per
Unit
Total AM
Peak
Hour Trip
Ends
PM Peak
Hour Trip
Ends per
Unit
Total PM
Peak
Hour Trip
Ends
Weekday
Trip Ends
per Unit
Total
Weekday
Trip
Ends
Residential
Apartment
(Blocks 1&13)
#221
216 0.37 80 0.39 84 4.54 981
Residential
Apartment
#221
222 0.37 82 0.39 87 4.54 1,008
Condominium/
Townhouse
#220
272 0.4 109 0.51 139 6.74 1,833
Single Family
Residential
#210
289 0.7 202 0.94 272 9.43 2,725
1st Floor Com.
Apartment
#231
84 0.44 37 0.36 30 3.44 289
Office
Park
#750
150 1.33 200 1.3 195 11.07 1,661
Shopping
Center
#820
155 0.84 130 3.4 527 37.01 5,737
TOTAL 840 1,334 14,234
Table 2 – Blocks 1 & 13 Trip Generation 2024 vs 2021
Blocks 1 & 13
ITE #221
Units
AM Peak
Hour Trip
Ends per
Unit
Total AM
Peak
Hour Trip
Ends
PM Peak
Hour Trip
Ends per
Unit
Total PM
Peak
Hour Trip
Ends
Weekday
Trip Ends
per Unit
Total
Weekday
Trip
Ends
New Proposal
with 11th Edition
Trip Gen. Rates
216 0.37 80 0.39 84 4.54 981
Previous
Proposal
with 10th Edition
Trip Gen. Rates
204 0.36 73 0.44 90 5.44 1,109
3
The small drop in overall trip generation will not have a significant impact on the results
of the LOS analysis for the planned project. The LOS analysis results from the 2021
addendum are shown in Table 3. The LOS analysis indicates that the proposed apartments
would increase delay at the study intersections, but the LOS will remain within acceptable
levels. The impacts from the apartments would be focused along the 19th Avenue corridor
with smaller levels of impacts along 11th Avenue and 3rd Avenue. The new plans for Blocks
1 & 13 will have the same impacts as those previously calculated.
Table 3 –Projected Level of Service Summary with Development
AM Peak Hour PM Peak Hour
Intersection Delay
(Sec.) LOS
Delay
(Sec.) LOS
19th Avenue & Graf Street 20.9 C 15.8 B
Kagy Boulevard & 11th Avenue 22.8 C 33.1 C
Graf Street & 11th Avenue 5.2 A 6.3 A
Graf Street & S 3rd Avenue 4.7 A 4.5 A
19th Avenue & Mid Approach 16.1 C 21.9 C
19th Avenue & Blackwood 22.2/14.7 C/B 24.1/18.6 C/C
S 3rd Avenue & Cambridge Dr. 16.2 C 11.4 B
Goldenstein Ln. & S 3rd Ave. 16.7 C 9.9 A
If you have any additional questions regarding the TIS for the Blackwood Groves
development, please feel free to contact me at 406-459-1443.
Sincerely,
Bob Abelin, P.E. PTOE
Abelin Traffic Services, Inc.