Traffice Lights along Shoreline Hwy - Coordinated Signal Timing Plan Update

County of Marin - Supervisor Sears


Update on Coordinated Signal Timing Plan for Current and Soon to Be Operational Traffic Lights along Shoreline Highway


Residents of Tam Valley and Almonte have been asking how the new signals at Flamingo and Tennessee Valley will work, especially in conjunction with current traffic lights at Almonte and at Manzanita.


The good news is that Caltrans is programming them so that they will work together. The plan is to time these signals to work together to create better coordinated traffic flow and the much needed bonus of safer streets for bicyclists and pedestrians.




Briefly, the soon to be operational traffic signal at Flamingo and Shoreline Highway was a required EIR mitigation measure for the Walgreens project built many years ago. However, its installation was delayed due to lengthy Caltrans review processes and funding shortfalls.  Bicyclists and pedestrians have been eager to see this traffic light installed for safe crossings from the neighborhood to the commercial areas. 


The Tennessee Valley signal responds to community requests to improve left turns and bicyclist and pedestrian crossings at that challenging location.


Here is information explaining why these locations warrant traffic signals and the more technical details about how they will operate.


Flamingo/Shoreline Highway (Hwy 1)


1)  The light at Flamingo was a Condition of Approval for Walgreens project at 227 Shoreline Hwy.

2)  Meets the peak hour Caltrans warrant for a traffic signal.

3)  Between 1/1/1999 and 12/31/2001, 11 collisions occurred during this 3 year period.  The fatality plus injury rate was slightly higher than the statewide average.  Although we do not have more recent collision data (it is under the control of Caltrans), we anticipate that the rates are similar but the number may have increased due to increased traffic volumes.  Most of the collisions were found to be attributable to the lack of traffic signal and separate left turn lanes.

4)  The traffic signal will be interconnected with the traffic signal at Almonte and Shoreline.

5)  The traffic signal will also improve bicycle and pedestrian access across the intersection.

6)  The Negative Declaration for the Walgreens study identified LOS (level of service) F on the side street without the traffic signal and overall LOS C at the intersection when signalized.


Tennessee Valley/Shoreline Highway (Hwy 1)


7)  The intersection meets 5 of the 8 Caltrans traffic signal warrants.

8)  The LOS at the intersection was LOS E in the AM and LOS C in the PM.  It was anticipated the LOS with the traffic signal will be LOS D in both the AM and PM peaks. (Note: It is difficult to compare levels of service here. First, the Shoreline Highway traffic is thru traffic at this location. Also, hard to compare a location with transition from stop sign to a one governed by a traffic signal.)

9)  Interconnection to the adjacent traffic signal was not required/included as part of the initial project. County traffic staff have contacted Caltrans suggesting the provision of a GPS clock, which Caltrans approved. A clock here allows Caltrans to program this light to synchronize with the other signals at Almonte and at Manzanita. 

10)       Bike and pedestrian access control will be provided at the intersection.




Please feel free to call my office at 473-7331 or e-mail me at