SAN DIEGO—Authorities sought Feb. 13 to determine what caused two big rigs to collide on Interstate 8 in Alpine this week, fatally injuring one of the drivers.

The trucker was killed about 6:30 p.m. Monday, when his eastbound tractor-trailer rear-ended a car-carrier truck near Tavern Road and caught fire, according to the California Highway Patrol. He remained unidentified late Monday morning.

The other driver, a 32-year-old Miami resident, was uninjured, the agency’s public affairs Officer Jared Grieshaber said.

The accident left the eastbound lanes of the freeway closed in the area for about 6 and half hours, the spokesman said.