Two motorcyclists were killed in a head-on collision Sunday on a winding stretch of the Ortega Highway west of Lake Elsinore, officials said.
Authorities shut down the highway in both directions for three hours during the investigation, snarling traffic on the major artery connecting Riverside and Orange counties.
The collision occurred when a motorcyclist heading east on the highway near Decker Canyon Road approached a curve at an "excessive speed" and crossed into the westbound lane, the California Highway Patrol said.
There, the rider crashed into a motorcyclist heading west at an unknown speed.
Firefighters were called to the scene about 10:30 a.m. Both riders, neither of whom were identified, died of their injuries.
All lanes of the highway were reopened shortly after 6 p.m.