Two people were injured Sunday morning after a head-on collision on Petaluma Hill Road north of Rohnert Park blocked traffic in both lanes.

The force of the impact sheered off the entire front end of one car, according the CHP incident log. One vehicle veered into a ditch, while the other, a small silver sedan, came to rest in the middle of the road following the 10:53 a.m. crash just north of Snyder Lane.

“Drug impairment is believed to be a factor in the crash,” CHP Sgt. Robert Boyer said.

Victims in both vehicles had to be extricated. Both were transported to Santa Rosa Memorial Hospital, a county fire dispatcher said.

Boyer said a woman who authorities believe was responsible for the crash suffered a broken hip and was hospitalized. The other driver suffered lesser injuries, he said.

Good Samaritans stepped forward to direct traffic until emergency responders arrived.

You can reach Staff Writer Meg McConahey at or 521-5204.