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Case Study

Prioritizing Transit on a Small Corridor, Dexter Avenue, Seattle

Year: 2013
Associated Publication: Transit Street Design Guide

The Seattle Department of Transportation (SDOT) uses in-lane stops to improve transit and bike safety and operations. During a scheduled resurfacing project of 1.5 miles of Dexter Avenue between Westlake Avenue North and Mercer Street—a segment with frequent bus service—SDOT seized an opportunity to reallocate space to transit by removing an existing center two-way left turn lane. The new configuration features one travel lane, a buffered bike lane, and a curbside parking lane in each direction, with left turn pockets only where needed.

To improve transit travel time and efficiency, bus stops were consolidated to an approximately quarter-mile spacing, allowing SDOT to build more robust and comfortable stops. At 10 of the 12 bus stops on the corridor, SDOT constructed dedicated transit islands, allowing buses to make in-lane stops for boarding passengers. The boarding islands are 10 feet wide and 80 feet long, and constructed using standard concrete. The islands are typically located at far-side stops at intersections with existing curb ramps at the sidewalk, simplifying the provision of accessible paths. Detectable warning strips were used to mark the edge of curb ramps, and all boarding islands are fully accessible.

At boarding islands, the buffered bike lane transitions to the right and is routed behind the bus stop, preventing conflicts between cyclists and stopped buses. The boarding island and bike channel is situated in the shadow of the parking lane, which resumes downstream of the island after the bike lane transitions back to the left. The corridor includes a pull-out stop approximately once per mile to allow vehicles queued behind the bus to pass, maintaining a balanced traffic flow.

Since implementation, bus boardings have increased by 23% along the corridor, and a motor vehicle traffic volume increase of 13% was accommodated, while vehicle travel time has been unchanged. The safety of the corridor has been measurably improved, with a 19% drop in the collision rate. Despite increased boardings at island locations, no conflicts have been reported between bicyclists and passengers. The enhanced stop design has successfully met the need for expanded transit capacity and overall street efficiency, while proving an attractive stop design for transit riders.