Santa Rosa traffic engineers are hoping a new kind of traffic signal will help drivers make better decisions when they make left turns at intersections in the city.
The city is the first in Sonoma County to install traffic signals with flashing yellow left-turn arrows.
While they may take some getting used to for drivers, engineers hope the new signals will reduce vehicle collisions by making it clearer that such turns need to be taken with care at intersections.
"These have been pretty successful in all the before-and-after studies that we've seen," said Bill Ellis, a city traffic analyst.
The new signals are being installed around the nation, following the lead of the Federal Highway Administration, which began allowing them a few years ago.
The first signal is going in at North Dutton Avenue and West Ninth Street. Engineers installed them Wednesday, but a software glitch prevented them from working properly.
"We had a little setback, but we'll get it running," said Traffic Engineer Rob Sprinkle, who said they will try again next week.
The intersection was selected for the first signals because it has an unusually high number of traffic accidents attributed to right-of-way confusion, Ellis said.
"People are getting into a similar type of collision out there consistently," Ellis said. "Year after year after year, we have the same things going on."
From 2004 to 2008, there were 51 traffic collisions at the intersection, 16 of them right-of-way accidents involving vehicles traveling north or south on North Dutton, he said.
Currently, drivers turning left from North Dutton onto West Ninth face what is known as a protected-permissive left-turn signal. A driver is first given a green left-turn arrow that gives them the right of way, thus "protecting" them from oncoming traffic.
But after a few seconds, the arrow turns off, switching to the regular "permissive" green light. This allows drivers to continue trying to turn left when there is a safe gap in oncoming traffic.