The main highway running through Saticoy in Ventura County is closed until at least midnight.
A truck hauling a trailer along a two-lane stretch of Highway 118 slammed into a telephone pole just after noon Wednesday.
Moments later, the pole snapped and was left partially hanging at an angle over the roadway.
The California Highway Patrol shut down the road between Vineyard and Rose Avenue for roughly 12 hours while crews repair the pole.
Motorists are using Central Avenue or Highway 101 as detours.