Three vehicles collided Wednesday morning on eastbound Highway 12 near Dutton Avenue in west Santa Rosa, sending two children to hospitals with apparently minor injuries.
The vehicles blocked an eastbound lane, causing an extensive traffic jam for more than an hour.
Initial reports indicated the children had been riding in a truck, which was seriously damaged.
One child suffered cuts to his face and other injuries and the other apparently had lesser injuries.
Callers reported the crash at 8:07 a.m.
About 30 minutes later, two vehicles collided on northbound Highway 101 north of Santa Rosa Avenue, the CHP said.
No one was reportedly injured but the wrecked vehicles blocked the carpool lane, adding to traffic congestion.