UPDATE 4:38 p.m. — The area is still highly congested. Traffic is backed up on both sides of Highway 99 because of the crash.
UPDATE 3:29 p.m. — California Highway Patrol says the big rig was hauling at least eight cars when it overturned.
The vehicles being hauled detached from the truck.
There is no estimate as to when the scene will be clear.
SACRAMENTO (CBS13) — An overturned car hauler is blocking a lane of southbound Highway 99.
This is just south of Elk Grove.
Caltrans says the #1 lane is closed because of the accident.
No one was reportedly injured in the crash. Drivers are urged to give themselves extra time if they are headed in that direction.