The driver of a big rig who apparently fell asleep at the wheel rear-ended two cars and crushed them against another semi, causing an explosion that killed four people Friday and backed up traffic for more than 30 miles on the main thoroughfare to Las Vegas, according to the California Highway Patrol.
The accident was the worst to occur this year on Interstate 15, which has seen an alarming increase in accidents since a freeway-widening project began two years ago. The route sees heavy Las Vegas-bound traffic at the start of each weekend, and the deadly accident brought traffic to a halt, stranding thousands. The northbound highway was expected to be closed until about midnight.
According to the CHP, northbound traffic had slowed just south of Lenwood Road at about 12:30 p.m. as cars made their way between rows of concrete barriers. One tractor-trailer driver failed to brake as he approached the mass of traffic and rear-ended an SUV and another unidentified vehicle.
The tractor-trailer continued to plow ahead and pushed the two passenger vehicles into the rear end of another big rig, causing the smaller vehicles to burst into flames. "Basically, they were pancaked between the two big rigs," said CHP Sgt. Daniel Laza.
Police and rescue workers had yet to identify the dead Friday evening, but said that one was an infant. Three of the four died instantly, authorities said, while the fourth, a woman, died at a hospital.
The accident remains under investigation. Laza said driver fatigue and truck speed appeared to be factors in the collision.
Neither of the big-rig drivers was injured.
The accident occurred in an area of fast-food restaurants and factory-outlet malls, and workers there said the collision and gridlock was the worst they could remember.
"There were a lot of flames," said Kenny Crespo, an assistant manager of Baja Fresh on Lenwood Road. "The trucks are still out there. Nobody's going anywhere for a long time."
Traffic tie-ups and deadly collisions are common on the I-15 in the high desert between Los Angeles and Las Vegas, particularly when thousands head to Nevada for the weekend.
However, crashes have been on the rise since work began in April 2002 to widen the freeway between Victorville and Barstow, according to the CHP. In some stretches, the number of accidents has more than tripled.
Crews have lined most of the 26-mile construction zone with heavy concrete barriers that, in some locations, are only inches from fast-moving traffic. Caltrans officials say the narrower shoulder and median space may have contributed to the increase in accidents by reducing the space motorists have to avoid slow or stalled vehicles.
In the first five months after construction began, collisions there increased 35%, to 50 accidents per month from an average of 37 per month during the same period the previous year, according to the CHP.
Injury and fatality rates remained relatively stable, suggesting that the additional accidents were mostly minor. On the entire stretch of Interstate 15 from Victorville to the Nevada border, CHP statistics show an increase in accidents of nearly 40% in the first 12 months after construction began. Fatality rates have not grown significantly, but injury rates have nearly doubled.
The $120-million widening project -- adding a lane in each direction -- was designed to accommodate traffic volume that has tripled since 1972. Caltrans engineers predict volume will double again -- to 100,000 average daily trips -- by 2025.
Times staff writer Hugo Martin contributed to this report.