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HomeMy WebLinkAbout008.01 - Appendix G.2 - Driveway Mod Request MONTANA | WASHINGTON | IDAHO | NORTH DAKOTA | PENNSYLVANIA 406.586.0277 tdhengineering.com 234 East Babcock Street Suite 3 Bozeman, MT 59715 September 23, 2024 Suzanne Ryan City of Bozeman Engineering Department PO Box 1230 Bozeman, MT 59771 Email: sryan@BOZEMAN.NET RE: ROUSE BLOCK B CONDOMINIUM BUILDING DRIVEWAY SEPARATION MODIFICATION REQUEST TD&H ENGINEERING JOB NO. B23-048 Dear Suzanne, Please find below, our justification for a modification to the City of Bozeman 40-foot driveway spacing requirement. Due to existing built conditions, adjacent property accesses to the east and the west, and the design requirements outlined for Block Frontage Standards in the UDC Section 38.510.030.M We are unable to meet the required 40-foot driveway spacing standard and therefore request a modification. The block frontage standards in the UDC Section 38.510.030, specifically mention section M.2.m, that requires the entrance to the parking areas must not be located central to the building. When you couple this with narrow adjacent lots and the existing built drive access entrances to the east and west of the project, there would be no opportunities to place a drive access for this building. The drive access has been placed adjacent to the access with the least amount of peak hour trips. Modification from Access Standards Discussion a. Traffic Volume: Peak hour traffic volumes for Babcock Street south of the Block B Condominium project were provided in the project traffic study and are summarized below. Peak AM Peak PM Existing Conditions (2024) 240 316 Full Buildout (2027) 250 328 Future (2039) 299 393 Only 22 vehicles are anticipated to enter or exit the garage during the AM peak hour and 25 vehicles are anticipated to enter or exit the garage during the PM peak hour. The existing single family residential driveway directly to the east of the proposed parking garage access that does not meet the 40-foot separation has only one AM and one PM peak hour trip 9/23/2024 September 23, 2024 PAGE NO. 2 tdhengineering.com based on the ITE Trip Generation Manual. This limits the potential for conflict between the driveways. b. Turning Movements: Babcock Street is a two-lane, one-way street running west to east. All turn movements into the parking garage and adjacent residential driveway are left turns in and left turns out. Traffic conflict is reduced as a result of only one possible turn movement. Additionally, the project consolidates three driveway accesses into one, reducing the number of conflict points along this stretch of Babcock Street. c. Traffic Control The proposed new access is a commercial driveway which does not require stop signs or other traffic control as stop control is implied for driveways. Traffic control is not proposed or typical for type of approach. An audible sound will be used in conjunction with the parking garage door to warn pedestrians when the door is opening and traffic is present. d. Site Design The Rouse Block B Condo site is primarily composed of the building footprint. A zero lot line frontage is proposed along Babcock Street with a 11.5-foot wide curbwalk style sidewalk between the building and street. Plantings will be installed in front of the building behind the curb. Planting will not be placed in the parking garage vision triangle. e. Sight Distance Babcock Street adjacent to the site is a local street with a 25 mph design speed. The parking garage access meets the City of Bozeman sight vision triangle requirements. The parking garage access is located directly upgradient of the traffic flow from the residential parking access that is within a 40-foot distance. Analysis of the parking garage access’s proximity to the residential driveway was completed to determine if a stopped car waiting to turn left onto Babcock Street would affect the City of Bozeman sight vision triangle for the residential access. It was determined that a parked car waiting to turn left onto Babcock Street will not affect the sight vision triangle of the residential parking lot allowing users of this driveway the minimum required site distance per the City of Bozeman code. The residential site vision triangle for the residential lot can be seen on sheet C3.1 in the site plan. f. Location and Alignment of Other Access Points The residential access east of the project is located 25 feet from the existing residential parking garage access. Due to City of Bozeman code requirements and parking garage ramp logistics, it is not feasible to place the parking garage access central to the building. In addition, an existing alley is located south of the proposed project at roughly the central point September 23, 2024 PAGE NO. 3 tdhengineering.com of the building that is more critical to maintain minimum code separation distance. Placing the parking garage access on the west end of the building would result in a similar setback condition from the parking lot west of the project which generates more peak hour trips and creates more potential conflicts. Given there are existing approaches directly west of the building (parking lot), central to the building (alley), and east of the building (residential driveway), the project has placed the garage access at the point of least potential conflict based the limited peak hour trips and use. Please feel free to contact me with any questions. Sincerely, Kyle Scarr PE Regional Manager TD&H ENGINEERING J:\2023\B23-048 Rouse Block B\05_DESIGN (TECH & REPORTS)\DESIGN REPORT\SP DESIGN REPORT\2024.09.23 DRIVEWAY MOD REQUEST.DOC