A collision involving a tractor-trailor and utility truck snarled westbound traffic on the Riverside (91) Freeway in Corona Tuesday morning.
The crash was reported about 8:30 a.m. west of Serfas Club Drive, according to the California Highway Patrol.
Injury information was not immediately available, although the CHP initially reported the driver of the utility truck was unresponsive after impact.
The vehicles came to a stop in the lanes of traffic, resulting in two lanes being blocked for about 50 minutes.
A Sig Alert was issued due to the traffic backlog.