San Rafael, CA - In response to comments and requests from the Tamalpais Valley and Mill Valley residents, the Marin County Department of Public Works (DPW) and Caltrans will restrict left (westbound) turns from northbound Tennessee Valley Road onto busy Shoreline Highway as a six-month pilot project starting August 22.
Concerns have been expressed regarding congestion along Shoreline Highway, also known as State Route 1, and conflicts with pedestrians and bicyclists crossing Shoreline Highway in the crosswalk. Elimination of left turns from Tennessee Valley Road onto Shoreline Highway is intended to address both concerns and will be evaluated through the pilot project.
Currently, left turns from Shoreline Highway and pedestrians/bicyclists crossing Shoreline Highway must go under separate signal phases to avoid conflict with left turns from Tennessee Valley Road. Those movements reduce the available signal “green time” for through traffic on Shoreline Highway. Elimination of left turns from Tennessee Valley Road will allow the other two movements to occur simultaneously and increase the “green time” provided to the through traffic on Shoreline Highway.
Further, left turns from Tennessee Valley Road are provided concurrently with the pedestrian movement across Shoreline Highway. Although the left-turn traffic must yield to pedestrians crossing Shoreline Highway, concerns have been expressed about the potential conflict and left-turn motorists not always seeing or anticipating the pedestrian and bicycle traffic. The left-turn restriction will remove the potential conflict.
The pilot program was devised after review of many suggestions and comments received by Marin County DPW, the City of Mill Valley and Caltrans. The County hired a traffic consultant to help review the comments and assess the proposed restriction. Although the new restriction is designed to improve flow and safety, up to 20 hourly left-turn movements from Tennessee Valley Road westbound toward Tam Junction will no longer be permitted and will thus inconvenience those motorists.
The left turn restriction will be implemented for six months to allow the public to observe traffic conditions and provide feedback. Signage, signal modifications and striping were being installed August 21 with the turn restriction to be fully active August 22.
Comments and suggestions may be sent to TVintersectionchanges@marincounty.org. County staff and Caltrans will review comments and prepare a recommendation about whether the restriction ought to be permanent.