Project Background
The SW Vermont St paving project will be among the first projects delivered under the Fixing Our Streets program funded by a local gas tax increase. SW Vermont St is a neighborhood collector street running east-west through a suburban residential neighborhood. The roadway carries approximately 8,000 vehicles per day and features Trimet bus service (lines 1, 45, and 64). Like many of the roadways in Southwest Portland, SW Vermont St features a rural design in segments with discontinuous bicycle and pedestrian facilities along the corridor. At the request of neighborhood advocates, the project team has been tasked with addressing some of these deficiencies within the scope of the project. To help accomplish this goal, a modest amount of additional funding may be provided from System Development Charges.
Existing Condition and Need
Bike/pedestrian connectivity along the SW Vermont St corridor between SW Idaho Dr (west of SW 45th Ave) and SW 52nd Ave concerns the neighborhood. A recently completed capital project had installed continuous bicycle lanes and southside sidewalk east of the SW 45th Ave (another neighborhood collector with a signalized intersection at SW Vermont St). However, the southside sidewalk extended only another two blocks west to SW Idaho Dr, and bike lanes terminated at SW 45th Ave. Neighborhood advocates strongly desire an improved bike/pedestrian connection to an existing neighborhood greenway facility which extends northward from SW Vermont St at SW 50th Ave and southward from SW Vermont St at SW 52nd Ave. The challenge for the project team is to develop a design concept that fulfills the desires of the neighborhood with the limited funding available.
Project Components
To address issues of pavement maintenance, SW Vermont from SW 30th Ave to the Portland city limit near SW 65th Ave was repaved. Any ramps that were not up to current ADA standards were upgraded. This type of paving maintenance will save Portlander's money by fixing issues before they get worse and cost more money to fix.
SW Vermont from 45th to 52nd: Alternative 1
In Street Southside Multiuse Path: To minimize costs, the first alternative is situated on the roadway surface. The existing continuous sidewalk facility west of this segment is on the south side of SW Vermont St, so the logical decision is to keep the pedestrian facility on the south side of the roadway to minimize pedestrian crossings. In this alternative, the multi-use path extended westward from the end of the existing sidewalk to link to the existing neighborhood greenway at SW 52nd Ave. Bike lanes connect the bike gap between SW Idaho Dr and SW 45th Ave. Westbound cyclists from the bike lane are routed to the frontage road to reach SW 50th Ave. The available pavement width in this situation is 36 feet. Given the presence of TriMet buses along this corridor, the recommended minimum travel lane width is 21 feet for two-way traffic. Ten feet is allocated to the eastbound direction since this travel lane is adjacent to a buffer zone. The westbound lane is allocated eleven feet since it is adjacent to the edge of pavement. A one-foot shoulder delineates the edge of pavement. A minimum three-foot buffer separates the eastbound travel lane from the multi-use path which takes the remaining eleven feet.
Advantages: Least expensive option, consolidates neighborhood greenway crossing at one intersection
Disadvantages: Lowest level of separation between pedestrians and traffic, largest distance of shared space between bikes and pedestrians, no shoulder space available for pedestrians on the north side of the street.
SW Vermont from 45th to 52nd: Alternative 2
Extend Southside Sidewalk & Add Bike Lanes: With a bit of extra investment, full separation between cyclists and pedestrians can be achieved within the segment of concern by extending the southside sidewalk west to SW 52nd Ave. This presence of the sidewalk provides the opportunity to widen the cross-section to 39 feet. In this option, the existing six-foot curb-tight sidewalk is extended westward. The remaining 33 feet of pavement is split into a 10.5-foot travel lane and a six-foot bike lane in each direction.
Advantages: Pedestrians fully separated from cyclists and auto traffic along entire corridor
Disadvantages: More expensive, doesn’t provide an 8-to-80 connection between the two legs of the neighborhood greenway, requires two separate crossings for cyclists to access the neighborhood greenway, does not accommodate crossing movements from bike lanes to neighborhood greenway streets well, No separate pedestrian space on north side (peds must use bike lane)
SW Vermont from 45th to 52nd: Alternative 3 (recommended by design team)
Multi-use Path & Sidewalk/Bike Lane Extension Hybrid: Alternative 2 still has several drawbacks. At slightly more cost, a hybrid of the first two concepts with the advantages of both appears feasible. In this option, the sidewalk corridor is widened in the segment between 50th and 52nd Avenues to function as a multi-use path similar to Alternative 1 while the cross-section from Alternative 2 remains in the segment east of SW 50th Ave where bikes and pedestrians may utilize the existing frontage road to avoid using SW Vermont St. Accommodating two-way bicycle traffic along the multi-use path segment frees up the space for a four-foot shoulder along the north side of SW Vermont St where the frontage road is not available.
Advantages: Provides 8-80 connection between neighborhood greenway streets, Consolidates neighborhood greenway crossings to one intersection, Better facilitates crossing movements between SW Vermont St and the neighborhood greenway streets, Provides adequate shoulder width for pedestrian activity along the north side of the roadway, Northside shoulder adds flexibility to address embankment and minimize potential need for retaining walls
Disadvantages: Most expensive option, shared use between cyclists and pedestrians for two blocks