Sound Transit has released new conceptual designs for the Stride bus rapid transit (BRT) project on SR-522 (also known as the S3 Line) and is hosting an online open house through August 23rd to gather feedback.

Key changes eliminate the Woodinville tail from the S3 Line, refine plans on how the line would reach a transit facility centered on the SR-522/I-405 interchange, and provide clarity on several stop consolidations and corridor right-of-way improvements. Sound Transit also released more details on transit-oriented development at the Kenmore park-and-ride and could use feedback there, too.

The S3 Line will serve the SR-522/NE 145th St corridor between the future Shoreline South/145th light rail station and I-405/SR-522 interchange in Bothell, essentially replacing ST Express Route 522, some time in 2024 or 2025 if the capital program realignment process does not further day things. At the I-405 interchange it will connect with the “S2 Line” in Sound Transit’s parlance for North I-405 Stride BRT. South I-405 BRT is the S1 Line for those keeping score at home, with transfers between S1 and S2 in Downtown Bellevue.

Woodinville tail gets the ax

Conceptual S3 Line corridor and stops with connecting lines. The western terminus is the park and ride and sure Shoreline South light rail station north of NE 145th Street. The line also serves two more stops on NE 145th Street, Lake Forest Park, Kenmore, Bothell. (Sound Transit)
Conceptual S3 Line corridor and stops with connecting lines. (Sound Transit)

While there has always been a question mark on the Woodinville tail, since it was never formally designated as a bus rapid transit-must, Sound Transit has been sour on the segment throughout the planning process. The latest concepts would entirely eliminate the Woodinville tail from the S3 Line and spin it off as its own ST Express bus route, which could come in two forms as a peak weekday variant and off-peak weekday and weekend variant. The new I-405/SR-522 transfer hub would be a critical transfer piece to both variants.

The conceptual layout of the I-405/SR-522 transfer hub. A bus loop is envisioned with a twisting maze of freeways and on- and off-ramps. (Sound Transit)
The conceptual layout of the I-405/SR-522 transfer hub. (Sound Transit)

Sound Transit has indicated that the new Woodinville route would run from the Woodinville Park-and-Ride to the Bellevue Transit Center with an interim stop at I-405/SR-522 transfer hub during peak weekday hours. At off-peak weekday periods and on weekends, the service would only run between Woodinville Park-and-Ride and the I-405/SR-522 transfer hub. Frequency under both operational variants would be every 20 minutes and no corridor improvements are proposed.

The agency plans to reach out for public feedback on the Woodinville tail service proposal in a separate process.

Station stop and right-of-way refinements

General S3 Line corridor with conceptual stops and improvements. (Sound Transit)
General S3 Line corridor with conceptual stops and improvements. (Sound Transit)

Sound Transit has dropped and consolidated some stations stops based upon feedback and corridor considerations.

Station consolidations in Kenmore and Lake City

In Kenmore, a station at 80th Ave NE was eliminated since public support was marginal. The street intersects with SR-522 and mainly only has developed blocks splintering off it north of the highway, but some of the blocks are well developed with multifamily uses. Nevertheless, the agency expects King County Metro to continue serving the stop with more local bus service, allowing riders to connect with the S3 Line further down the line if desired. The nearest S3 Line station stop will be located five blocks further to the west at the Kenmore Park-and-Ride.

On NE 145th St, Sound Transit has dropped the 25th Ave NE and Lake City Way NE station stops. Instead, these station stops have been consolidated to a new location about halfway between at 30th Ave NE. This puts a station stop three blocks west of Lake City Way NE and 15 blocks (about a mile) from the intermediate NE 145th St stop at 15th Ave NE. A station at 30th Ave NE would provide for connections to other local bus routes and proximity to the Lake City Hub Urban Village. It also would be directly serve low-income public housing operated by the Seattle Housing Authority. The east side of the urban village and the business district on Lake City Way, however, would be farther away than they would have been with a stop on Lake City Way stop in Seattle.

Even though the S3 Line will not serve the 25th Ave NE stop, Sound Transit reports that Metro will continue to do so at high frequencies with local service to the Shoreline light rail station. Likewise, the stops at NE 145th St and Lake City Way NE will continue to be served by local Metro bus service.

Right-of-way design changes

In Bothell, Sound Transit has identified design changes to how the line will operate on city streets and corresponding improvements. The S3 Line leaves SR-522 at 98th Ave NE running only on local streets to reach I-405. This will effectively mean skirting around the city center via NE 185th St while still providing two station stops that offer city center access. To aid bus movements on NE 185th St, Sound Transit hopes to implement speed and reliability improvements at intersections and in the roadway.

Bothell service will also run Beardslee Blvd with no deviations directly into the UW Bothell/Cascadia College campus. Proposed station stops, however, would still provide reasonable walking access to the main upper campus areas. The line terminus at that I-405/SR-522 transit hub would have direct trail access to the lower portion of the campus.

Just south of the main city center, Sound Transit is planning to construct business access and transit (BAT) lanes in the northbound direction of SR-522, though battles over the Yakima Fruit Stand continue. Other BAT lanes near Bothell’s western city limits are already under construction on SR-522.

One additional conceptual change for Bothell has led Sound Transit to slightly move the future park-and-ride. Originally, this facility had been planned right at Pop Keeney Stadium but is now being shifted a little south to Lot P South sought in order to reduce property impacts. A total of 300 parking spaces are proposed as part of the facility.

In Lake Forest Park, conceptual design changes have been made for the footprint of SR-522 to accommodate BAT lanes and where BAT lanes and related speed and reliability improvements are proposed. Driveways and property access have been an issue on the east side of SR-522 for a segment between NE 155th St and just south of 41st Ave NE. This has led to Sound Transit consider some right-of-way expansion on the west of SR-522 in the area.

Sound Transit generally proposes right-of-way changes in Lake Forest Park that would modify road configuration between NE 145th St and just north of NE 165th St. Part of this involves adding new roadway but also removal of the two-way left-turn pocket lane in order to provide BAT lanes in both directions, new sidewalks, and a raised median. Compensating for the median barriers, new U-turns would be permitted at some intersections. However, the agency anticipates no changes to the median between NE 145th St and NE 155th St.

In Shoreline, progress on conceptual changes have largely come in the form of roundabouts near the I-5 interchange with NE 145th St. The City of Shoreline has been spearheading the effort with the state and other local jurisdictions to construct two such roundabouts. The idea behind the roundabouts is that traffic flow will improve over the use of stoplights, which is critical to keep buses moving to and from the light rail station planned just north of the I-5/NE 145th St interchange off of 5th Ave NE.

Conceptual design for the new NE 145th St roundabouts. (City of Shoreline)
Conceptual design for the new NE 145th St roundabouts. (City of Shoreline)

If built, the roundabout would certainly be a big improvement over the status quo, especially for people walking, biking, and rolling to and from the station with safer and more accessible routes. Wait times at intersections should also be much less for transit trying to move along NE 145th St or reaching the station. The roundabout project is still in the design phase and is anticipated to cost another $25 million to complete.

Kenmore transit-oriented development

Finally, Sound Transit noted that some progress has been made on the Kenmore Park-and-Ride garage, which is supposed to deliver 300 parking stalls at the existing park-and-ride lot. In coordination with Metro and the City of Kenmore, Sound Transit hopes to include transit-oriented development as part of the project. Several design workshops were held last year to discuss a path forward to realize both objectives.

Early concept of the future Kenmore park-and-ride garage with TOD arranged in four six-story buildings. (Sound Transit)
Early concept of the future Kenmore park-and-ride garage with TOD. (Sound Transit)

The existing park-and-ride property is about seven acres, but inclusion of adjacent properties like the St. Vincent de Paul and Schnitzelbank could increase that by several acres. An early conceptual design, however, would only include the St. Vincent de Paul site. All told, the conceptual design contemplates four primary apartment buildings with some mixed-use and new parking garage situated to the southeast.

Bus and bus base progress

  • Planned bus base location. (Sound Transit)
  • Preliminary site plan layout of the bus base. (Sound Transit)

In support of the S3 and S2 Lines, Sound Transit is earnestly planning a new 12-acre bus base in Bothell’s Canyon Park. An environmental checklist and decision on the facility was issued on Monday with a determination of nonsignificance (DNS), meaning that environmental impacts are anticipated to be relatively minor and no mitigation is required. The comment period on the DNS is open through August 24th.

On top that, federal government just came through with a $4.8 million grant on Tuesday that will assist in purchase of buses and bus equipment specifically for the S3 Line. Both construction of the bus base and acquisition of a bus fleet will also be critical elements of the S3 Line in order to launch.

Next steps

Sound Transit expects to continue the planning and design process through 2023. Formal selection of the project to build should occur later this year with board approval and construction on the bulk of project elements is anticipated to begin in 2023, though some work is already underway in Bothell on SR-522. Give feedback through August 23rd in Sound Transit’s online open house on the project and any desired refinements.

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Stephen is an urban planner with a passion for promoting sustainable, livable, and diverse cities. He advocates for smart policies, regulations, and implementation programs that enhance urban environments by committing to quality design, accommodating growth, providing a diversity of housing choices, and adequately providing public services. Stephen primarily writes about land use and transportation issues.

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