A suspected drunken driving crash Wednesday in San Marcos left a 59-year-old motorcyclist severely injured and his 40-year-old passenger with minor injuries.

The pair was headed north on North Twin Oaks Valley Road approaching La Cienega Road around 5:15 p.m. Tuesday when the man lost control of the motorcycle, according to San Diego Sheriff‘s Deputy C. Morreale. Both the motorcyclist and his passenger were thrown to the ground.

Morreale said the man was apparently not wearing his helmet correctly because it came off during the crash. He suffered major head trauma and numerous abrasions. The passenger, a woman, was wearing a helmet and suffered abrasions in the wreck, Morreale said.

Both were taken to Palomar Medical Center to be treated, although the woman was not admitted, according to the deputy.

Morreale said the preliminary investigation indicated that alcohol may have been a factor in the crash. He asked anyone who saw the crash to call (760) 510-5045 or (858) 565-5200.

Chris Jennewein is founder and senior editor of Times of San Diego.