LOS ANGELES, CA — Moments after taunting and tailgating another driver, a mother and daughter were killed in a devastating wrong-way collision on the Golden State Freeway in Sylmar when they sideswiped a car and crashed head-on into a truck, authorities said Wednesday.

As Sandoval slammed on the brakes he saw that Morales' car had been cut in half.

In what police said may be a case of "road rage," the two women chased an unidentified van to the end of the Roxford Street offramp, then made a U-turn, spraying mud onto the van.

The car continued south into the northbound lanes, striking the truck. The two women in the car, driver Delfina Gonzales Morales, 42, and passenger Maria Laura Morales Gonzales, 26, were killed instantly, witnesses said.

Northbound lanes of the freeway were closed for more than four hours after the 7:20 a.m. accident, which created a massive traffic jam and horrified commuters who witnessed the crash.

The truck driver, Victorino Raul Martin Perez, 27, was not injured in the accident.

"I don't want to remember it," he said, too shaken to describe the crash. "I was really scared by it. I just want to go on with my life like nothing happened."

CHP spokesman Doug Sweeney blamed the accident on Morales, saying that it was a predictable outcome of this kind of highway violence.

Morales had just dropped a grandchild off at school, authorities said.

Federal Express driver Jessie Sandoval, who was northbound on the freeway, said he knew something was wrong when cars on either side of him began to swerve and flash their brake lights.

Sandoval, who was making his daily run from Los Angeles International Airport to his Lancaster station, saw the truck 300 feet in front of him abruptly stop and topple onto its side.

As Sandoval slammed on the brakes he saw that Morales' car had been cut in half. Engine parts were strewn all over the freeway, Sandoval said.

"I got out to help," he said. "I knew they were dead right away."

George DeMott, 58, was starting to pass the truck on the left when pieces of metal flew against his windshield and the truck leaned over his car.

"I didn't see what hit it," said DeMott, a 33-year veteran of the Los Angeles City Fire Department. "But that truck was tipping over and came down on top of me."

Two-thirds of the 42,000 highway deaths in 1996 were directly related to aggressive driving.

DeMott, who said he was traveling about 65 mph, jerked the wheel farther to the left, hitting the guardrail and coasting 500 feet down the freeway. His passenger side had caved in.

"I'm glad I didn't have anybody sitting next to me," he said. "They would have been killed for sure."

DeMott also stopped to help the women in the car, but stopped short.

Witnesses told police that Morales tailgated the van, flashed her lights, honked her horn and made obscene gestures moments before the accident.

Morales had just dropped a grandchild off at school, authorities said.

Sweeney urged other motorists not to get engaged in highway confrontations and to call the police if they are threatened in a similar manner. "It's not worth it," he said.

Two-thirds of the 42,000 highway deaths in 1996 were directly related to aggressive driving, according to testimony last year before a House transportation subcommittee.

In 35% of the cases, a vehicle was used directly as a weapon.

Researchers define aggressive driving by certain types of behavior, such as speeding, illegal lane changes and running red lights. Road rage is when that sort of aggressive driving is taken to an extreme.

A study by the AAA Foundation for Traffic Safety that sought to quantify road rage looked at 10,000 aggressive driving accidents reported around the nation since 1990. The study indicated that in 35% of the cases, a vehicle was used directly as a weapon. Men between the ages of 18 and 26 were the drivers most likely to be involved in aggressive driving accidents, the study indicated.

About 10% of overall traffic deaths occurred in California, which has a larger population and more vehicles on the road than any other state. Even so, the state had fewer deaths per mile driven than the national average, a record the Highway Safety Administration attributes to safety programs and the highest rate of seat belt use in the nation — 85%.

Although aggressive driving has been on the rise nationwide, statistics show that it has been most deadly in the Pacific Northwest. Five drivers or their passengers have been killed in road rage incidents there since 1993, and there have been shootings in the past several weeks.

The AAA found a direct correlation between driver anger and increased traffic congestion. Since 1987, the number of miles of roadway in the United States has increased just 1% while the number of vehicles competing for space on those roads has exploded 35%, Highway Safety Administration officials reported.

The CHP has asked that the driver of the van involved in the initial incident with Morales' vehicle contact authorities.