SAN DIEGO (CNS) - Authorities released the names Wednesday of two motorists killed last weekend in a collision involving a car headed the wrong way on Interstate 8 in Ocean Beach.

Zachary Quiroz, 22, was driving a 2009 Volkswagen to the east on the westbound side of the freeway near Sunset Cliffs Boulevard for unknown reasons when a 2004 Honda Accord approached shortly before 1 a.m. Sunday, according to the county Medical Examiner's Office and California Highway Patrol.

The driver of the Honda, 37-year-old Andrew Warnock of San Diego, tried in vain to steer clear of the oncoming car, the CHP reported. The vehicles collided nearly head-on, mortally injuring both motorists.

Medics took Quiroz, the sole occupant of his car, to UCSD Medical Center in Hillcrest, where the Escondido resident was pronounced dead about an hour after the accident.

Warnock succumbed to his injuries at the scene of the wreck. His two female passengers, ages 30 and 34, were transported to a hospital for treatment of moderately serious trauma.

It remained unclear this afternoon if intoxication played a role in the collision, CHP public-affairs Officer Jake Sanchez said. The results of blood-toxicology tests for the drivers were pending, he said.

Investigators also were working to determine how Quiroz might have wound up on the wrong side of the freeway, the spokesman said. The wreck occurred near the terminus of the freeway, where large "do not enter" signs are posted alongside the westbound lanes.