The accident happened at 9:19 a.m. The trailer of the rig crashed onto the road below while the cab was left dangling over the side.
Officials said the driver of the big rig managed to free himself from the wreckage. He was transported to a local hospital with moderate injuries.
The 91 transition road and the Artesia onramp to the southbound 710 Freeway were closed for much of the day.