Sammamish presents three Sahali Way alternatives; council asks for cost, traffic and geotech detail

City staff presented three refined alternatives for the Sahali Way Corridor study to the Sammamish City Council on Sept. 2, asking the council to review tradeoffs among transit access, pedestrian and bicycle comfort, and corridor cost and resilience.

The corridor matters because Sahali Way is the city’s only direct transit connection to East Link light rail in Redmond, staff said. Audrey Starcey, the city’s public works director, told council: “we heard all of your great comments and inquiries” and that staff will return Oct. 7 with a recommended preferred alternative and more analysis.

The study packages include: Alternative A, a transit- and safety-focused approach with minimal widening (estimated $20.8 million); Alternative B, adding continuous sidewalk and pedestrian separation (about $37.5 million); and Alternative C, a full multimodal option with separated bike facilities and multiple roundabouts (about $78.9 million). Staff also presented two refinements—"B1," which adds traditional bike lanes plus a 35 mph posted limit (about $38.6 million), and "C1," a cost-reduced version of C that narrows some south-end improvements (about $72.1 million).

Senior project engineer Jed Ireland summarized safety tradeoffs: “Roundabouts are 1 of the options that are proven to reduce speeds,” and noted that roundabouts were a major driver of public opposition to the highest-cost alternative. Staff described other speed- and safety-management tools that could be used in place of roundabouts, including rapid-flashing beacons or HAWK signals, and said crosswalk and transit-stop improvements would be phased to prioritize near-term transit access and future light-rail connections.

A central technical constraint is slope stability. Staff told the council that sections of the corridor sit on ancient landslides; that some areas already require dewatering systems; and that any corridor widening would likely require more extensive wallwork and higher resiliency measures that add cost. Staff said they are monitoring ground movement with inclinometers and will provide a geotechnical risk/cost analysis as part of the Oct. 7 return.

Council members pressed staff for more detail on cost drivers and on traffic-model sensitivity. Council member Pamela Stewart asked the team to “tease apart” whether the south-end cost difference between alternatives was driven primarily by roundabouts, by widening to add protected bike lanes, or by both; Deputy Mayor Amy Lam asked whether a shared-use path could be inserted into Alternative B to reduce cost while improving bicycle safety. Staff agreed to return with refined cost breakdowns and traffic simulations showing travel-time differences under 35 vs. 45 mph scenarios and with and without roundabouts.

Staff said draft intersection performance runs show no “projected failures” across the alternatives but committed to returning with more detailed intersection-level travel-time and sensitivity information. They also emphasized that the corridor plan is a 20-year vision to be constructed in phases; near-term phasing will prioritize crossings and intersection controls that increase immediate access to East Link.

No formal decision or vote was taken. Staff will incorporate council feedback on costs, geotechnical mitigation options, bicycle treatments (shared-use path versus protected lanes), and transit stop/pullout design and return to council on Oct. 7 with geotechnical analysis and a recommended preferred alternative.

Next steps: staff will prepare the geotechnical resiliency report and a refined cost breakdown, and will present a preferred alternative and phasing recommendations at the Oct. 7 council meeting. Detailed engineering would follow in 2026 if council adopts a preferred corridor plan.