Lake Forest Park outlines detour plan, phasing and community impacts for SR 104 roundabout project

Mike Reed, the City of Lake Forest Park’s Senior Project Manager, provided a community update on the SR 104/40th Place NE roundabout project and described a traffic‑management plan the city says will limit daytime full closures while accommodating utility work, retaining walls and a stormwater detention vault at the intersection.

Reed said project design was completed in early 2025 and the construction contract was awarded in fall 2025; the city has postponed moving dirt while it resolved conflicts with Seattle City Light poles, water‑main alignment and other sequencing issues. "We're hoping by the end of July, early August," Reed said when asked about a potential start window for construction.

The city presented a phased work plan that begins in the southeast quadrant and proceeds counterclockwise. During the early phase where tree removal, grading, wall construction and utility relocations occur simultaneously, the city will reduce 40th Place NE to a single lane at the northeast approach. Reed said the single‑lane approach and modeled operations supported a single‑lane roundabout rather than a multi‑lane approach, noting additional lanes would have required more right‑of‑way and introduced unsafe weaving.

Traffic counts collected on the corridor informed the detour concept. The city reported roughly 150 southbound vehicles per hour in the morning peak and about 90 southbound in the afternoon peak; northbound flow was lower in the morning (about 45 vehicles/hour) and higher in the afternoon (over 200 vehicles/hour). To preserve northbound capacity the city plans to divert most southbound 40th Place NE traffic to 35th Avenue and maintain two‑way flow on SR 104 for most of construction.

Reed emphasized the contractor’s original full‑closure proposal was rejected by the city. Instead, the plan calls for a 30–40 day partial‑closure interval late in the schedule when crews will construct three quarters of the intersection, shift traffic within the roundabout footprint and then complete the final quarter. Reed said final paving, channelization and other finishing work will be done overnight during a short full‑closure window to avoid daytime disruption.

Utility work and other site constraints shaped sequencing. Reed showed a rectangular detention vault planned under the center island and described tall soldier‑pile walls (the tallest exposure roughly 15 feet at the high point) and gravity block walls (typically 4–7 feet exposed). Reed also said the Lake Forest Park Water District will replace and slightly realign a water main to avoid the vault. Tree removals on all four corners were acknowledged; the city is studying canopy replacement options.

The city said staging and material storage will be contained within the immediate work zone and that Johansen is the contractor. Reed also said the city will install infrastructure for pedestrian‑activated push buttons at crosswalks as part of a change order, at minimum leaving conduit and mounting capacity so buttons can be added without later rework.

Reed noted the corridor paving was last done in 2001 and that the city plans to pursue a larger complete‑street effort from the roundabout to SR 522 in coordination with the Lake Forest Park Water District and potential Transportation Improvement Board (TIB) funding in future years.

On operations and enforcement, Reed said local access—including police, fire and pedestrian circulation—will be maintained and the city’s police department will provide emphasis patrols and monitoring during detours. He acknowledged some residential streets may require additional barricading or local‑access restrictions if cut‑through traffic increases.

Rebecca Dickinson, a program executive with the city, encouraged residents to submit requests through the city portal for sidewalk, crosswalk or traffic‑calming items outside the roundabout scope so the city’s traffic calming group can evaluate and respond.

Resident Jim Stetzer asked where equipment would be staged; Reed said all staging would be located within the immediate work zone and not stored offsite. Residents raised other operational questions—truck restrictions at dead‑end approaches, bike accommodations (design practice is to keep bicycles in the travel lane), and exact wall facades—many of which Reed said will be resolved in final design or answered offline and posted to the city website.

Next steps: the city will continue coordination with Kenmore, Shoreline, King County Metro, the school district and WSDOT to finalize detour corridors and seek conceptual acceptance from WSDOT for the regional routing and potential signal‑timing changes. Reed said the city will publish a phasing schedule and e‑blast to explain the timing and access plans once they are finalized.