Sammamish officials defend traffic model as residents and commissioners press for more local counts and corridor analysis

City of Sammamish transportation staff and their consultant, DKS, spent the bulk of the Planning Commission’s Nov. 20 meeting explaining how the city models current and future traffic, how projects are prioritized and funded, and what the next steps are in implementing the Transportation Master Plan (TMP).

The presentation, led by Audrey Starcey (Director of Public Works) and Ben Stabler (DKS National Director of Modeling and Analytics), described a three-part toolkit: observed traffic counts, a VISUM travel-demand model for long-range forecasts and Synchro/Sidra tools for intersection-level operations. Stabler said the approach is industry standard and that calibration against observed counts produced a close match in the base year. "Modeling is one of the best ways we can do it in a reasonable, rational, structured way to do our best to estimate and, you know, drive decisions with data and analysis," he said.

Why it matters: residents and commissioners asked whether those tools capture the day-to-day experience on Sammamish roads. Several speakers produced photos of long vehicle queues at key…