Motorists will be required to give bicyclists three feet of clearance when passing if Gov. Jerry Brown approves legislation now on his desk.
The proposed law has extensive backing from the Sonoma County bicycling community, which sees it as an opportunity to educate motorists as well as provide some protection to cyclists on the area's windy, narrow roads.
"It gives everybody a more clear understanding of what is the safe distance to pass a bike on the road," said Sandra Lupien, outreach director for the Sonoma County Bicycle Coalition. "While people might know you have to pass safely, having the law adds legitimacy and gives cyclists a way to hold drivers accountable."
The bill was authored by Democratic Sen. Alan Lowenthal of Long Beach and would replace language in the vehicle code that requires passing at an unspecified safe distance.
Eighteen states already have the three-foot rule and four others recommend it in their driver manuals.
"This is a widely accepted standard," said John Casey, a staff member in Lowenthal's office.
While most cyclists have stories of being startled after being "buzzed" by a motorist passing too closely, being hit by a passing vehicle is actually the least common collision.
"Most people are amazed at that statistic," said Gary Helfrich, the coalition's executive director. "There is a public perception the biggest safety issue is being hit from behind. What this law helps do is give people a little more confidence about riding on the road."
The consequences of such a collision are serious, usually resulting in a severe injury or fatality, Helfrich said.
Anoush Zebarjadian of San Francisco suffered a severe head injury and was hospitalized for months when he was struck by the side mirror of a vehicle the CHP believes passed intentionally close during the King Ridge GranFondo last Oct. 9.