Westbound lanes of Highway 58 were delayed after a crash involving a big rig near Keene, the California Highway Patrol reported.

The truck crashed onto its side just before 11 a.m. on the westbound side of the freeway at mile marker 139, officials reported.

Westbound traffic was backed up for two miles following the crash, with drivers going an average of 16 mph, according to 23ABC's Traffic Now system.

Photo By James Hobbs

CHP dispatchers reported that some drivers may be passing the crash on the shoulder of the roadway.

It's unclear whether the truck driver was injured in the crash.