Traffic was snarled for about two hours on the eastbound 210 Freeway in Irwindale on Friday morning after a collision involving two big rigs, one of which was carrying a trailer that overturned.
There were no immediate reports of injuries.
The crash occurred about 3:47 a.m., just west of Irwindale Avenue (map), and initially resulted in the closure of all lanes on the eastbound side, according to an incident report from the California Highway Patrol. The agency issued a Sigalert at 4:09.
One lane was reopened by 4:45 a.m., aerial video showed. The other four lanes were reopened as of 6:15 a.m. and the Sigalert was canceled, the CHP said.
It was unclear what caused the incident. One of the big rigs jackknifed in the collision, and one of its two trailers overturned. Crews were working to turn the trailer upright before removing it from the scene.