SAN MATEO — A 22-year-old man was killed early Saturday morning when the car he was driving crashed off of Highway 92 and landed on El Camino Real below, authorities said.

The man was driving east on the freeway around 1 a.m. when, for reasons the California Highway Patrol said are still under investigation, his 2017 Acura left the road.

The car struck a dirt embankment, flipped over and then crashed into El Camino’s concrete center divide, authorities said.

The driver, who has not been publicly identified, died at the scene.

No other cars were involved.

El Camino was closed in both directions for about an hour and a half as authorities investigated the crash.