All traffic on westbound state Route 78 at Mar Vista Drive was diverted to Sycamore Avenue for most of Sunday morning after a 33-year-old woman from Oceanside was killed in a fatal chain-reaction crash overnight, the California Highway Patrol (CHP) said.
The highway was reopened shortly before 4:30 p.m.
The woman drove her Toyota Corolla off the roadway to the right before veering to the left across traffic, striking the center divider around 2:15 a.m., CHP said.
A 54-year-old man driving a Scion XB struck the Toyota, pushing it onto its side. The woman was ejected from the Toyota and later pronounced dead at the scene.
A 38-year-old man driving a Scion XC also struck the Scion XB.
The 54-year-old man was taken to the hospital with major injuries. The 38-year-old man and his two passengers were transported with minor injuries.
The 38-year-old man and the 54-year-old man may have been under the influence of alcohol or drugs, CHP said.
The investigation is ongoing.