Big Rig Overturns, Shutting Down All Southbound 5 Freeway Lanes In Castaic A big rig overturned Monday morning, shutting down all southbound lanes of the 5 Freeway in Castaic, officials said. UPDATE: 10:45 a.m. — Three lanes are now open on the southbound 5 Freeway near Templin Highway, with the No. 4 lane closed for an estimated three hours, according to the California Highway Patrol. The crash was first reported at about 6:20 a.m. Monday on the southbound 5 Freeway south of Templin Highway, according to Officer Josh Greengard, spokesperson for the California Highway Patrol (CHP) Newhall Area Office. “A semi-truck overturned, blocking all southbound lanes,” Greengard said.