District 3 Community Update on Shoreline Highway

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Community Update on Shoreline Highway
and Tennessee Valley Road

Working to Restore Traffic Flow on Shoreline and the Tennessee Valley Road
Right Turn Movement

Thank you for inquiring about traffic congestion at Tam Junction. I have received many calls and e-mail messages of concern about the traffic signal timing along Shoreline Highway, which has been causing traffic congestion and delays. County traffic engineers have forwarded your comments to Caltrans staff responsible for timing of the traffic signals on Shoreline Highway and are in frequent contact with them. 

Marin County Public Works is working with Caltrans to do the following:

  • improve the flow of traffic through the several traffic lights in and around Tam Junction, and
  • restore the right turn out of Tennessee Valley Road to help motorists trying to exit the Valley from that location.

Background on the Installation of the Traffic Light at Tennessee Valley Road and Balancing Commuter Needs

The signal at Shoreline Highway and Tennessee Valley Road was installed in order to provide a safe and accessible pedestrian and bicycle crossing across Shoreline Highway, which previously was dangerous and difficult. The signal also facilitates left turns from Tennessee Valley Road onto Shoreline Highway, which was previously unsafe and often impossible due to the heavy flow of traffic in each direction.

The reason for congestion in the peak a.m. and p.m. commute hours is the number of both roadway and pathway users that converge at Tam Junction at the same time.

The Safe Routes to Schools program has documented remarkable success encouraging Mill Valley School District students and parents to travel to school on bikes and on foot rather than by car. According to student surveys in the spring of 2013, fully 33% of all Mill Valley students walk or bike to school and 16% carpool. In the Tam Valley area, 26% walk or bike. Mill Valley Middle School reports 42% walk or bike, and 22% walk or bike to Tam High. For all three schools, 32% walk or bike.

The result is a need to balance the flow of automobiles out of the Valley with the flow of students walking and on bicycles trying to cross Shoreline Highway at multiple locations here and at Almonte and Miller Avenues. Pedestrians headed to the Dipsea Cafe could often be seen sprinting across this busy highway. Community members as well as the Sheriff’s office and California Highway Patrol have voiced concerns about safety. The light at Tennessee Valley Road gives pedestrians and cyclists this long sought opportunity for a safe crossing.

Coordination with Caltrans to Remedy Congestion via Adjustments to Light Timing on Shoreline and Road Striping at Tennessee Valley Road

The adjustment of signal timing and the road striping requirements are solely within Caltrans’ jurisdiction, which creates challenges. While the new traffic light was requested by the County of Marin to facilitate pedestrian and bicycle access to the newly built Tennessee Valley pathway along Coyote Creek, Caltrans owns and maintains Shoreline Highway/State Route One.

During review of the signal installation plans, a separated right turn from Tennessee Valley Road was considered, but Caltrans staff expressed concerns regarding visibility for right-turning motorists. They were concerned motorists would not be able to see the red, yellow or green traffic signal indicators from a separated right turn lane and would enter traffic assuming they had the right of way. We have heard complaints from many of you about the current striping.

County Department of Public Works traffic engineers are working with Caltrans to explore whether it would be possible, based upon current field conditions, to remove the cross hatched striping and allow a separated right turn from Tennessee Valley Road onto Shoreline Highway. Caltrans and County staff also are working to reduce commute delays. Caltrans has made adjustments to the signal timing to increase the time on the “through movement” on Shoreline Highway.

The County is also consulting with a third party traffic signal operations expert to get additional input. I hope this approach yields measurable success we can all see and experience soon.  

Marin County Public Works Data Collection Documenting the Problem

Marin County Public Works traffic engineers have been driving a loop from Tam High through Manzanita Park and Ride during the morning commute hours. Their results are shown below. They noted that commute hour traffic coincides with many cars dropping off students at Tam High, as well as scores of kids on bikes on the Almonte bike lanes and the Mill Valley-Sausalito bike path.

The traffic engineers also confirmed the large number of cars northbound on Hwy 1 turning left onto Tennessee Valley Road – each time they drove the loop the turn pocket was full (7-8 cars). Only on one lap did the traffic engineers observe a large number of cars backed up on Tennessee Valley Road; once the light turned green, approximately 20 cars made the right turn onto Hwy 1.  No cars were turning left.

Driving loop: Tam High to Almonte to Shoreline & Tennessee Valley to Manzanita

Time passed Tam HS parking lot                 Time to get to Hwy 101 off ramp signal

7:35 AM                                                            4:00 minutes

7:45 AM                                                            6:30 minutes

8:00 AM                                                            17:00 minutes

8:22 AM                                                            12:00 minutes

8:42 AM                                                            3:00 minutes

8:52 AM                                                            4:00 minutes

9:06 AM                                                            4:00 minutes

All of this information is being transmitted on a daily basis to Caltrans signal timing engineers. We anticipate receiving direction from Caltrans within the next two to four weeks. Thank you for your patience as we continue to work with Caltrans to adjust signal timing based upon the day to day conditions staff is observing in the field.

If you have comments or questions, please feel free to direct your messages to my office and/or to the following agencies and elected representatives:

Phillipe Van, Senior Transportation Engineer
Caltrans, District 4- Traffic
(510) 286-4589

Einar A. Acuna, Senior Transportation Electrical Engineer
Caltrans, District 4 - Signal Operations
(510) 622-5741

Vanessa Chuang
Transportation Electrical Engineer, Signal Operations
Caltrans, District 4 – Signal Operations

State Legislators/Representatives:
State Senator Noreen Evans
(415) 479-6612

Carole Simon Mills, District Representative
(415) 470-6612

Assemblymember Marc Levine
(415) 479-4920

County of Marin:
Supervisor Kate Sears

Maureen Parton, Aide to Supervisor Sears
(415) 473-7331

Bob Goralka, Marin County Public Works, Transportation Division Manager
(415) 473-6570

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