A driver nodding off behind the wheel caused a head-on collision early Tuesday morning. That same driver was the only injury from the crash, the California Highway Patrol reported.

The collision happened around 4 a.m. Monday on W. Main Street in an area between Turlock and Patterson.

John A. Williams III, 20, of Patterson was driving a 2003 Acura TL west on Main Street at an estimated 55 miles per hour. Williams later told investigators he fell asleep while driving, allowing the vehicle to drift into the eastbound lane. The left front of the Acura collided with the left front of a 2013 Peterbilt, causing both vehicles to come to an abrupt stop on the road, the CHP reported.

Williams was pinned in his vehicle and was freed by emergency responders. He sustained moderate injuries, including a suspected broken ankle and facial lacerations. He was taken to Doctors Medical Center for treatment.

The driver of the Peterbilt, Jaime Melgoza, 49, of Atwater was not injured, according to the CHP.

The conditions were foggy at the time of the collision, though investigators said it was not a factor in the crash. The fog did prompt the CHP to close the area to motorists while they investigated the collision and cleared up the debris.

Alcohol and drugs were not considered factors in the collision.