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Home My WebLink About012 - Traffic Technical Memo MEMORANDUM To: Parker Lange, Development Manager From: Joey Staszcuk, PE, PTOE, RSP1 Date: September 7, 2023 Reference: SRX Development, GPA/ZMA – Traffic Technical Memo The purpose of this memo is to provide a trip generation comparison for the projected zone change of the proposed SRX Development in Bozeman, Montana. The site was originally zoned as a Residential Low Density (R-1) and Residential Moderate Density (R-2) and the proposed change is to a Community Business-Mixed (B-2M) and Residential Emphasis Mixed-use (REMU). The total external trip generation projections for the existing R-1 and R-2 zoning totaled 1,278 average weekday trips, with 93 trips during the AM peak hour and 122 trips during the PM peak hour for the full development. Densities for the above totals were determined based on similar, already developed areas in Bozeman with R-1 and R-2 zoning. These projections assumed the following land uses and densities: 40 single-family attached units and 105 single-family detached units. The existing zoning trip generation table is attached on page 3. The total external trip generation projections for the proposed B-2M and REMU zoning totaled 4,427 average weekday trips, with 215 trips during the AM peak hour and 394 trips during the PM peak hour for the full development. The new land use densities for the SRX Development are listed as follows: 50,000 square-foot supermarket, 17,500 square-foot strip retail plaza, 200 multifamily units, and 50 single-family attached units. This is an increase of 3,149 total external weekday trips, with 122 additional trips in the AM and 272 trips in PM peak hours. The proposed zoning trip generation table is also attached on page 3. The 2017 Bozeman Transportation Master Plan (TMP) provides roadway capacities and expected 2040 volumes for roadways throughout Bozeman. Since the TMP has been published many roadway projects have been completed which have resulted in increased roadway capacity. For example, South 19th Avenue north of Graf Street now has two thru lanes in each direction, South 19th Avenue south of Graf Street has two northbound thru lanes, and Graf Street west of South 19th Avenue has a two-way left-turn lane (TWLTL). The attached figure shows the original TMP capacity as well as the updated capacity since improvements have been completed. Updated capacities were determined based on similar roadway sections in Bozeman. New weekday vehicle trips, accounting for a reduction in internal capture, were assigned to adjacent roadways based on a distribution previously determined from an adjacent Traffic September 7, 2023 2 Impact Study. Both expected weekday vehicle trips and the distribution are shown on the attached figure. Additionally, the net change in trips was determined by subtracting trips that would have been generated by the current zoning from trips generated by the proposed zoning. This net trip total was then added to the predicted volumes listed in the 2040 TMP. The predicted 2040 volumes listed in the TMP are assumed to be representative of all future development and growth in the area. The attached figure shows updated expected 2040 volumes, denoted in the key as “TMP 2040 Volumes + New Weekday Trips.” Based on the above listed assumptions all roadways show an expected 2040 volume that is below the roadway capacity, although Graf Street and South 11th Avenue are nearing capacity. The proposed change in zoning from R-1 and R-2 to B-2M and REMU is expected to result in a large increase in traffic demand but is not anticipated to exceed roadway capacities based on information from the 2017 TMP. If you have any questions or concerns, please feel free to contact me at 406-922-4306 or jstaszcuk@sandersonstewart.com. Sincerely, Joey Staszcuk, PE, PTOE, RSP1 Senior Engineer | Community Transportation Studio Manager GHC/jhs Enc: Trip Generation Tables Traffic Volume Figure P:22318_South_40_TIS_Bozeman_GPA/ZMA_9.7.2023 September 7, 2023 3 Intensity Units total enter exit total enter exit total enter exit 105 Dwelling Units 990 495 495 74 19 55 99 62 37 40 Dwelling Units 288 144 144 19 6 13 23 13 10 1278 639 639 93 25 68 122 75 47 (1) Single-Family Detached Housing - Land Use 210* Units = Dwelling Units Average Weekday: Average Rate = 9.43 (50% entering/50% exiting) Peak Hour of the Adjacent Street, One Hour between 7 and 9 AM:Average Rate = 0.70 (25% entering/75% exiting) Peak Hour of the Adjacent Street, One Hour between 4 and 6 PM: Average Rate = 0.94 (63% entering/37% exiting) (2) Single-Family Attached Housing - Land Use 215* Units = Dwelling Units Average Weekday: Average Rate = 7.20 (50% entering/50% exiting) Peak Hour of the Adjacent Street, One Hour between 7 and 9 AM:Average Rate = 0.48 (25% entering/75% exiting) Peak Hour of the Adjacent Street, One Hour between 4 and 6 PM: Average Rate = 0.57 (59% entering/41% exiting) *Trip Generation, 11th Edition, Institute of Transportation Engineers, 2021 **Trip Generation Handbook, 3rd Edition , Institute of Transportation Engineers, 2017 Table 1. Trip Generation - Current Zoning - R-1 & R-2 Independent Variable AM Peak Hour Single-Family Attached Housing2 Full Buildout New External Trips PM Peak Hour Land Use Average Weekday Single-Family Detached Housing1 Intensity Units total enter exit total enter exit total enter exit Supermarket1 50 1000 SF GFA 4692 2346 2346 144 85 59 448 224 224 239 113 126 1 0 1 36 21 15 1603 804 799 52 31 21 148 73 75 17.5 1000 SF GFA 953 477 476 41 25 16 115 58 57 49 23 26 0 0 0 10 6 4 307 154 153 14 9 5 36 18 18 200 Dwelling Units 908 454 454 74 17 57 78 48 30 206 109 97 1 1 0 34 14 20 50 Dwelling Units 360 180 180 24 7 17 29 17 12 82 43 39 0 0 0 12 5 7 6913 3457 3456 283 134 149 670 347 323 576 288 288 2 1 1 92 46 46 1910 958 952 66 40 26 184 91 93 4427 2211 2216 215 93 122 394 210 184 (1) Supermarket - Land Use 850* Units = 1000 Sq. Ft. GFA Average Weekday: Average Rate = 93.84 (50% entering/50% exiting) Peak Hour of the Adjacent Street, One Hour between 7 and 9 AM:Average Rate = 2.88 (59% entering/41% exiting) Peak Hour of the Adjacent Street, One Hour between 4 and 6 PM: Average Rate = 8.95 (50% entering/50% exiting) (2) Strip Retail Plaza (<40k) - Land Use 822* Units = 1000 Sq. Ft. GFA Average Weekday: Average Rate = 54.45 (50% entering/50% exiting) Peak Hour of the Adjacent Street, One Hour between 7 and 9 AM:Average Rate = 2.36 (60% entering/40% exiting) Peak Hour of the Adjacent Street, One Hour between 4 and 6 PM: Average Rate = 6.59 (50% entering/50% exiting) (3) Multifamily Housing (Mid-Rise) - Land Use 221* Units = Dwelling Units Average Weekday: Average Rate = 4.54 (50% entering/50% exiting) Peak Hour of the Adjacent Street, One Hour between 7 and 9 AM:Average Rate = 0.37 (23% entering/77% exiting) Peak Hour of the Adjacent Street, One Hour between 4 and 6 PM: Average Rate = 0.39 (61% entering/39% exiting) (4) Single-Family Attached Housing - Land Use 215* Units = Dwelling Units Average Weekday: Average Rate = 7.20 (50% entering/50% exiting) Peak Hour of the Adjacent Street, One Hour between 7 and 9 AM:Average Rate = 0.48 (31% entering/69% exiting) Peak Hour of the Adjacent Street, One Hour between 4 and 6 PM: Average Rate = 0.57 (57% entering/43% exiting) *Trip Generation, 11th Edition, Institute of Transportation Engineers, 2021 **Trip Generation Handbook, 3rd Edition , Institute of Transportation Engineers, 2017 Full Buildout New External Trips Full Buildout Internal Capture Trips Full Buildout Pass-By Trips PM Peak Hour Internal Capture Trips** Internal Capture Trips** Strip Retail Plaza (<40k)2 Internal Capture Trips** Internal Capture Trips** Pass-By Trips** (Avg. Rate = 34%) Full Buildout Gross Trips Land Use Average Weekday Multifamily Housing (Mid-Rise)3 Single-Family Attached Housing4 Pass-By Trips** (Avg. Rate = 36%) Table 2. Trip Generation - Proposed Zoning - B-2M & REMU Independent Variable AM Peak Hour September 7, 2023 4