The Highway Patrol says, the driver of a fully loaded gravel truck, jumped from the cab and let the vehicle crash on San Marcos Pass this morning.
The truck was coming from a rock quarry near Lake Cachuma.
The accident occurred about 8:15 a.m.
An investigation showed, the driver was unable to stop the vehicle as it came down a roadway to Highway 154 at 15 to 25 miles per hour.
Investigators say the driver jumped from the truck and it went across the normally busy highway into an dirt embankment.
A portion of the roadway was closed while the truck was hauled away.
The Highway Patrol has not released information on what the driver will be cited for.