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A Traffic Safety Evaluation Report for the City of Petaluma was completed by the Institute of Transportation Studies at University of California Berkeley in collaboration with the City of Petaluma Police Department to evaluate the protected/permissive left-turn signal operations. The study was initiated because right-of-way collisions at intersections surpassed speed collisions as the highest cause of collisions in Petaluma. Right-of-way collisions are defined as those accidents that are not related to speeding but are caused when a driver neglects to yield the right-of-way to another vehicle.

In an effort to reduce these types of collisions, the City of Petaluma will replace the solid green light protected/permissive signal with a flashing yellow arrow signal at 13 intersections.

This new signal configuration has been implemented successfully in other states and is beginning to be utilized in California. A study conducted by the National Cooperative Highway Research Program found that drivers made fewer mistakes with flashing yellow left turn arrows than with traditional yield-on-green signal configurations.

How to use a flashing yellow left-turn arrow

It’s simple! Just remember that a flashing yellow left-turn arrow means, first yield to oncoming cars, bicycles and pedestrians, then turn left with caution.

Before entering the intersection, look left and look straight ahead. Ask yourself, is there any oncoming traffic? Are there any on-coming pedestrians or bicyclists?

Remember, on-coming cars, bicycles and pedestrians will have the right-of-way. Once you determine it is safe to do so, make your left turn. During the traffic cycle, you will see the flashing yellow left-turn arrow change to the better-known solid yellow left-turn arrow. The solid yellow left-turn arrow means what it has always meant: that the signal is about to turn red and you should prepare to stop.

What You Will See and How It Works!

  A solid red arrow means STOP. Drivers turning left must stop.
The solid yellow arrow indicates the signal will be changing to red and drivers should prepare to stop.
  A flashing yellow arrow means turns are permitted, but you must first yield to oncoming cars, bicycles and pedestrians and then proceed with caution.
  A solid green arrow means turn left. On-coming traffic has a red light and must stop. Do not go straight.


Roadway Standards

The flashing yellow left-turn signal is in both the State of California’s and the Federal Highway Administration’s Manual on Uniform Traffic Control Devices (MUTCD). These are standard for signs, signals, and pavement markings in California and the United States.


Informational Brochure - ENGLISH
Information on how to use a flashing yellow left-turn arrow signal.

Folleto Informativo - ESPAÑOL
Información sobre cómo utilizar un semaforo con flecha amarilla intermitente para girar a la izquierda


California Driver Handbook
Traffic signal light instructions for drivers.


US Department of Transportation approval for use of flashing yellow left-turn signals


If you have questions or comments about the flashing yellow left-turn signal, please contact the Traffic Engineering Division at 707-778-4303 or email


Affected Intersections

Bodega at Bantam S McDowell Blvd at Maria
Bodega at Webster S McDowell Blvd at McGregor
Frates at Calle Ranchero Petaluma Boulevard North at Sycamore
N McDowell Blvd at Community Center Petaluma Boulevard South at I Street
N McDowell Blvd at E. Madison Petaluma Boulevard South at Mountain View
N McDowell Blvd at Redwood Way Sonoma Mountain Parkway at Rainier
S McDowell Blvd at Caulfield  



Contact Information

11 English Street
Petaluma, CA 94952
phone: 707.778.4303
fax: 707.206.6034
Hours: 8:00 A.M. - 5:00 P.M.
Monday - Thursday

Director, Public Works and Utilities
Dan St. John, F.ASCE
202 N. McDowell Blvd
Petaluma, CA 94954
Phone: 707.778.4546
Fax: 707.206.6034

Assistant Director, Public Works and Utilities
Jason Beatty
202 N. McDowell Blvd
Petaluma, CA 94954
Phone: 707.778.4514
Fax: 707.206.6034

City Engineer/Flood Plain Administrator
Gina Benedetti-Petnic, C.E.
11 English St
Petaluma, CA 94952
phone: 707.778.4311

Airport & Marina Manager
Joshua McKeighan
601 Sky Ranch Drive
Petaluma, CA 94954
phone: 707.778.4404
fax: 707.778.4405

Transit Manager, Jared Hall
555 North McDowell Blvd
Petaluma, CA 94954
phone: 707.778.4460
fax: 707.776.3799