JAMUL — Two drivers suffered serious injuries in a head-on crash on state Route 94 in Jamul on Thursday morning, authorities said. The crash occurred about 5:25 a.m. just east of Vista Sage Lane, California Highway Patrol Officer Travis Garrow said. A 20-year-old Chula Vista man behind the wheel of a westbound 1999 Honda Civic crossed over into the eastbound lane and slammed head-on into a 2017 Subaru WRX driven by a 22-year-old San Diego man, Garrow said. Both drivers were taken to Sharp Memorial Hospital in San Diego for treatment of serious injuries, which were not believed to be life-threatening, the officer said.