We have an update on what caused the crash on I-90 where a semi truck went off the highway and into a ravine Thursday evening.

According to Pennsylvania State Police, the driver reportedly fell asleep behind the wheel which resulted in the semi swerving into the right shoulder, then striking and traveling through a guiderail.

PSP reports the semi continued down a steep embankment and eventually stopped approximately 50 yards off the highway. Rescue personnel used a stokes basket and ropes to bring the driver up the ravine.

The driver was pulled from the cabin and transported to UPMC Hamot to be treated for what were described as minor to moderate injuries.

The crash backed up traffic on Interstate 90, and a detour was put in place until crews cleaned up the mess.