PALA - Four North County residents - a pair of married couples - were killed in a fiery crash on Highway 76 late Friday when the compact car they were in collided head-on with a sport utility vehicle just before midnight, and the two-lane road was closed for seven hours, authorities said.

The driver of the larger vehicle was expected to be charged with manslaughter, the California Highway Patrol said.

The San Diego County medical examiner's office identified the victims as Jesus Desantiago, 45, and Lina Desantiago, 46, of Escondido, and Luis Baez, 51, and Rubi Baez, 46, of Vista. Investigator James Buckley said the couples were riding in the same car, a 2005 Toyota Camry, driven by Jesus Desantiago.

The accident occurred at 11:51 p.m. while the Camry was heading west on Highway 76 in the North County backcountry, about two miles east of Pala Mission Road. The Camry collided with an eastbound 2005 GMC Yukon being driven by Anthony J. Boles, 24, of Palm Springs, the California Highway Patrol reported.

"For an unknown reason, Boles allowed the Yukon to drift onto the right shoulder of State Route 76 eastbound, colliding with the metal guardrail that borders the north road edge," the Highway Patrol stated in a news release. "Boles lost control of the Yukon as it crossed over the double yellow lines into the westbound lane."

The force of the collision knocked both vehicles onto their roofs, blocking the highway's westbound lane, the Highway Patrol said.

The Camry's right-front passenger, Luis Baez, was flown by a Mercy Air helicopter to Scripps Memorial Hospital La Jolla, where he was pronounced dead upon arrival, authorities said. The other three victims died at the scene, Buckley said.

Boles and a passenger, 23-year-old Deanna Fridley, also of Palm Springs, were rescued from the upside-down Yukon by passers-by who stopped to help, the Highway Patrol said. Boles and Fridley were taken to Palomar Medical Center in Escondido for treatment of serious injuries, authorities said.

"Boles will be charged with manslaughter and felony DUI (driving under the influence) when he is released from the hospital," the Highway Patrol said.

Boles was listed in good condition and Fridley was in critical condition late Saturday, said Andy Hoang, a hospital spokesman.

According to a Highway Patrol dispatcher, the accident and the investigation triggered the closure of the section of the highway between Agua Tibia Avenue and Magee Road until 7 a.m. Saturday.