Highway 154 was closed in both directions near Lake Cachuma late Thursday afternoon after a vehicle went off the side of the road.
It happened shortly after 4 p.m. along the westbound side of the highway, about one mile west of the San Marcos Golf Course.
According to the Santa Barbara County Fire Department, the vehicle was found 100 feet over the side of the road in the riverbed.
The male driver was reportedly trapped under the vehicle and suffered major injuries. He was taken by hospital to a local hospital.
The California Highway Patrol is investigating the cause of the crash.
