A jacknifed big rig and three other vehicles caused a traffic snarl in Walnut Thursday, forcing closure of an entrance ramp.
The crash on the westbound Pomona (60) Freeway, at Fullerton Road, was reported about 11 a.m.
The wreck sprawled across the carpool, two left and one middle lane, according to California Highway Patrol Officer Tatiana Sauquillo.
A SigAlert was issued for a far right, the middle and a far left lane, the officer said.
It took about 40 minutes to clear the wreck but no injuries were reported.