A single-vehicle collision early Saturday morning on Highway 99 in Turlock seriously injured a Ceres man, the California Highway Patrol reported.

The collision happened around 2 a.m. Saturday on Highway 99, near West Main Street.

Leonel Dias, 24, of Ceres was driving a 2001 GMC SUV that for an unknown reason he allowed the vehicle to drift off the east side of the highway.

The GMC struck a metal bridge railing and then plunged down the embankment before coming to a stop on West Main Street.

The Turlock Fire Department responded to the scene and crews used specialized stabilization struts and heavy extrication equipment to free Dias. He was transported to an area hospital with major injuries.

Dias was wearing a seatbelt.

The CHP said drugs and alcohol were not factors in the collision. The investigation is ongoing