A Sig alert was issued in the San Pasqual Valley area Tuesday after an overturned big rig was blocking the road.
The incident occurred around 18500 block of San Pasqual Valley Road, according to the San Diego Police Department (SDPD).
It's unknown what led up to the crash.
The Sig alert was expect to last until 6 p.m., police said.
Motorists were advised to use an alternate route.
No other information was available.