Updated 3:55 p.m.:
All but the middle lane of southbound SR 57 at the wesbound 60 interchange were reopened at 3:30 p.m.
There were reports that the driver of the sedan slid across all southbound lanes, then overcorrected, before colliding with the big rig.
Four people were injured Saturday in a crash involving a big rig and a Toyota sedan on the 57 Freeway in Diamond Bar, prompting freeway closures, and an airlift, authorities said.
The crash on the southbound State Route 57 at the eastbound 60 Freeway interchange, was reported at 1:05 p.m., according to the CHP.
According to California Highway Patrol Officer Jennifer Cassidy, one person was airlifted to a trauma center.
Callers reported an occupant of the Toyota trapped, the California Highway Patrol indicated on its incident log.
All lanes of the 57 were closed at the westbound 60, the CHP reported.
According to the incident log, the Toyota slid under the big rig.
A SigAlert was issued for the road closure and was to remain in effect at least until 4 p.m., the CHP reported.