Crashed cars and emergency vehicles blocked a Highway 101 lane in Petaluma during Tuesday's morning commute, said the CHP.
Two vehicles collided in southbound lanes near the Petaluma River bridge at about 8 a.m.
The crash aftermath eliminated a lane of traffic and slowed the commute through the area, according to CHP reports.
An ambulance took one person to Petaluma Valley Hospital with minor injuries and the lane was cleared by about 8:30 a.m.
Southbound commuters had further troubles to face down the highway, with a crash south of Novato involving three vehicles blocking lanes.
That crash occurred at about 8:05 a.m., south of DeLong Avenue.
A bumper from a truck in the crash had broken off and was also blocking a lane.
The crash was moved to the side of the highway by 8:25 a.m. but traffic appeared to be greatly slowed back to northern Novato, according to the CHP.
An ambulance also was called to the Marin County crash, but the extent of injuries wasn't initially available.