A woman died early Friday after a crash involving a big-rig on eastbound state Highway 4 in Concord, according to the California Highway Patrol.
The woman was driving a Honda Accord that collided with the rear of the tractor-trailer about 6:30 a.m., just east of Willow Pass Road, the CHP said.
Emergency crews arrived and the woman was pronounced dead at the scene. Her name has not been released.
The driver of the big-rig was not injured, the CHP said.
Alcohol or drugs are not suspected in the crash, but it is still under investigation. Anyone with information about the collision is asked to contact Contra Costa CHP in Martinez, at (925) 646-4980.