Flashing Yellow Left Turn Signals

Reducing Collisions


In 2013, the City of Santa Rosa installed the first flashing yellow left-turn arrow signal in Sonoma County, at the intersection of W Ninth Street and Dutton Avenue. This intersection has been the site of numerous left turn accidents where motorists attempting left turns collided with oncoming vehicles. A signal equipped with a flashing yellow left-turn arrow has been shown to reduce these types of collisions.

Configuration of Signals


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 turn with caution, after yielding to oncoming cars, bicycles and pedestrians. Before entering the intersection, look left and look straight ahead. Is there any oncoming traffic? Are there any on-coming pedestrians or bicyclists?

Oncoming cars, bicycles and pedestrians will have the right-of-way. Once you determine it is safe to do so, make your left turn. After the flashing yellow left-turn arrow you will see 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.

Roadway Standards


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

Additional Information


If you have questions or comments about the flashing yellow left-turn signal, please contact Massoud Saberian, Supervising Engineer, at 707-543-3818.