Looking south at Stony Point Road and Petaluma Boulevard North in Petaluma: The
traffic light at upper left gives drivers turning left a green arrow at first.
Road Warrior photo.
Petaluma drivers are finding — some times the hard way — that a green light doesn’t always mean go.
Sometimes it’s because how the traffic signal works is confusing to drivers, and the city is moving to change that.
Last year, right-of-way violations became the No. 1 cause of collisions in Petaluma for the first time since the Police Department began keeping track in 1986. There were 118 such crashes.
In analyzing the crashes, Police Sgt. Ken Savano said officers found that most of the collisions occurred at intersections where drivers can turn left after yielding on a solid green light and that some drivers were confused by the type of green light.
He said the city has two types of left-turn lights: Protective and protective/permissive. The protective lets drivers turn on a green arrow, followed by a yellow arrow and then a red arrow, which bars any left turn. The other type of green light — protective/permissive — appears to be the confusing one: A green arrow, followed by a yellow arrow and then a solid green ball.
Then the traffic light shows a yellow arrow to warn drivers that their right of way to
turn left is ending. Photo by a Road Warrior reader.
Savano said many drivers think that the solid green ball allows them to keep turning left and that oncoming traffic has a red light. Instead, the solid green ball allows left turns only after yielding to oncoming cars, which do have a green light and the right of way.
As a result, he said, left-turn drivers are turning in front of oncoming cars and getting hit. Some crashes occurred on multiple-lane roads where drivers turning left didn’t notice or see cars in both oncoming lanes.
After the yellow arrow ends, the traffic light at upper left just shows a green light,
which Petaluma officials say is proving confusing to drivers turning left: Not all
realize that they now have to yield to oncoming traffic when turning left.
Road Warrior photo.
Savano said the city installed the non-red arrow lights to improve traffic flow, allowing drivers to turn when safe rather than just sit at the red arrow even if there was no oncoming traffic.
He said the city has received grant money to replace the potentially confusing signals at high-collision intersections with the one that includes the red arrow in an effort to reduce crashes.
City Engineer Curt Bates said the city is just beginning its analysis of the intersections and will recommend to the City Council which ones should be converted.
Santa Rosa Police Sgt. Rich Celli said Santa Rosa has several protective/permissive traffic signals, with some prone to collisions and others not. He said the city is focusing on Dutton Avenue at Ninth Street, where there have been several left-turn accidents, and plans to figure out a fix.
