A shooting on Highway 4 in Concord wounded a driver and shut down part of the freeway for several hours early Wednesday, authorities said.

The California Highway Patrol received reports of gunfire at 10:40 p.m. Tuesday. Officers soon learned that a 25-year-old Oakland man who had shown up at Kaiser Permanente Medical Center in Walnut Creek had been shot in the leg while driving west on Highway 4 east of Port Chicago Highway.