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HomeMy WebLinkAbout28 Streets, Roads and AlleysThe Lakes at Valley West Subdivision – Phases 1 and 2 Preliminary Plat Application Streets, Roads and Alleys The Lakes at Valley West Subdivision will be served by a number of street sections; including minor arterial, collector, local and woonerf sections. The dedicated rights-of-way for each of these sections vary based on city requirements. A Road Section Index (Figure 1) has been created that illustrates where each section is located. There are street cross section exhibits as well for each of the roadways (Figures 2 – 5). Roadway intersections within The Lakes will match the design of existing intersections within all of Valley West Subdivision. Curb bulbs will be continued in order to reduce traffic speeds and allow for safer pedestrian crossings. Curb bulbs will also be used at mid-block/trail corridor crossings. Parking will not be allowed where curb bulbs are located. An intersection index (Figure 6) has been created to help illustrate the design of each intersection type within the subdivision. Individual lots in general will not access directly to the arterial streets or collector streets. “No access” strips will be placed on lots fronting Durston Road and Laurel Parkway. Access to these fronting lots will be provided off of either a local street or woonerf. All streets will be paved to provide long-term dust control. Dust created during construction will be controlled in accordance with the Montana Public Works Standard Specifications. Surface drainage is shown on the preliminary grading and drainage plan. Surface runoff will be treated by on-site detention/retention facilities. Erosion control plans will be prepared with the construction documents. All erosion control plans will be in accordance with state and local regulations. A permit for Storm Water Discharges Associated with Construction Activity will be required by MDEQ for all phases of the project. Construction sediment will be controlled in accordance with the standard practices described in the Montana Sediment and Erosion Control Handbook. The applicant will pay for construction of all streets and woonerfs within the subdivision, including portions of Durston Road (Minor Arterial) and Laurel Parkway (Collector). Funding scenarios for improvements to these roadways are further discussed in Section 30. All maintenance for public streets will be by the City of Bozeman. Maintenance in paved woonerfs will be the responsibility of the homeowner’s association for items such as snow removal, cleaning, and weed control. Major maintenance items such as asphalt repairs will need The Lakes at Valley West Subdivision – Phases 1 and 2 Preliminary Plat Application to be addressed by the homeowner’s association, as they are needed. A snow removal exhibit has been created to illustrate primary locations for snow storage. See Figure 7. A comparison between a woonerf section and a standard local street section is provided to illustrate the similarities in both sections. See Figure 8 [and four (4) color graphics immediately following Figure 8]. This comparison illustrates that the woonerf has essentially the same width as a local street section. In response to concerns surrounding emergency access to properties with the subdivision, we have prepared fire truck turning templates for several locations throughout the subdivision. Locations include; a local intersection with curb bulbs, typical woonerf intersections and a woonerf circle (shown in future Phase 3). All modeling was done utilizing an AASHTO S-BUS- 40 which, according to the Bozeman Fire Department, is a comparable vehicle to mimic the department’s fleet of fire trucks. See the modeling exhibits at the end of the section labeled Fire1, Fire 2 and Fire 3. The Traffic Impact Study for the subdivision addresses traffic generation. The traffic study is included in Section 29. The Gallatin County Road and Bridge Department has been sent a letter requesting their input regarding the proposed subdivision. Copies of correspondence are included in Section 40. Offsite Roadways Modifications to Durston Road will be made during individual phases of the project. The Applicant is interested in working with the City and other owners in the area to construct the remainder of Durston Road from North Cottonwood Road to the western edge of the project, as well as Laurel Parkway to the southern terminus of the property. Funding for these projects is always a concern and the applicant is prepared to work with the City of Bozeman to come up with a reasonable solution that will benefit multiple users. Please refer to Section 30 for further details on Durston Road and Laurel Parkway. Based on pre-application review comments, the south half of Durston is to match the already constructed north half in terms of geometry, lane widths, etc. The Durston Road dedication on the south side will be 50 feet as opposed to the 45 feet dedicated on the north side. As noted in Section 9, and engineering access separation relaxation is hereby being requested from Table 38.24.090-3. Durston Road will have approximately 628 feet between Laurel Parkway and Westmorland Drive (to back of curb) which is slightly less than the minimum of 660 feet. The location of this access has been shown on multiple PUD submittals since the early 2000’s and remains in this same location on this Preliminary Plat. The reason for this access location is that Bronken Park is located immediately to the east, which contains Baxter Creek and the associated Baxter Creek Natural Area. The wetlands associated with this area and the The Lakes at Valley West Subdivision – Phases 1 and 2 Preliminary Plat Application Baxter Creek 50’ watercourse setback (as shown on Exhibit A in Section 17) prevents the access from meeting the 660 feet access separation. Roundabouts and Traffic Circles As part of the layout and design of the Lakes at Valley West, we looked at whether roundabouts and/or traffic circles could be a viable alternative to a more traditional intersection. We looked at two intersections as part of Phases 1 and 2, Durston Road/Laurel Parkway and Laurel Parkway/Westmorland Drive. Durston Road/Laurel Parkway We looked at a conservatively sized roundabout right of way at this intersection, roughly 190 - 200 feet in diameter. With this approximate size, rights of way on adjacent private property would need to be acquired, including the subdivision to the north, Laurel Glen, which does not appear to have provided right of way or easements to allow said improvements. The geometric elements of a roundabout in this location were not addressed previously, but could be if the City of Bozeman desires to construct a roundabout as part of the overall Durston Road/ N. Cottonwood Road improvement project. It would be necessary for the roundabout design and right of way/easement acquisition to commence immediately, along with the rest of the subdivision design, in order to maintain construction schedules. The timeframes associated with a roundabout (ROW acquisition, design and construction) would most certainly be longer than the timeframes associated with a more traditional intersection. With that said the developer is open to a roundabout discussion with the city but would need assurances that the increased timeframes associated with a roundabout would not impinge on the developer’s construction schedule. The increased cost of a roundabout would also need to be discussed. Based on the right of way needs, impacts to existing private property, increased timeframes and increased cost we feel that a roundabout is not warranted at this time. Laurel Parkway/Westmorland Drive This is a collector/local street intersection. We analyzed both a roundabout and a traffic circle at this location. Laurel Parkway being a collector indicates that a large roundabout would be required due to anticipated traffic volumes, whereas the local streets would indicate that a smaller traffic circle would be appropriate in order to slow neighborhood traffic. This intersection will also need to be designed to handle a significant amount of pedestrian traffic as it is adjacent to a large park and open space. Based on this we feel that this collector/local intersection would better function in a more traditional layout as The Lakes at Valley West Subdivision – Phases 1 and 2 Preliminary Plat Application opposed to a roundabout/traffic circle. The pedestrian controls associated with the traditional layout, including curb bulbs, will allow for safer pedestrian crossing movements.