Four people died in traffic accidents on Utah roadways Saturday.

A Tooele man was killed and his passenger injured the vehicle they were riding in flipped over an embankment in Tooele County and burst into flames.

The accident happened where Drouvay road turns from pavement to gravel between Tooele and Lake Point, said deputy Shandey Lewis of the Tooele County Sheriff's Office.

The started sliding uphill and hit a railroad track that intersected the road, she said, sending the car airborne. A witness managed to pull the passenger, Curtis Richman, 19, from the burning vehicle but couldn't rescue the driver, Eric Cruz, 21, Lewis said.

Richman was flown in critical condition to the University of Utah Hospital, she said. Authorities believe speed and alcohol were factors.

In a separate accident, drowsy driving apparently caused a rollover that killed a 53-year-old woman from La Verkin on I-15 near Washington City, said Utah Highway Patrol spokesman Jesse Valenzuela. The accident happened about 6:30 a.m.

The driver of a van apparently fell asleep, hitting the woman's sports utility vehicle, sending it rolling into the median, Valenzuela said.

When her van came to a rest in the median, "vehicle number one slammed into it," instantly killing the woman, Valenzuela said. The van's driver, a 21-year-old from Ivins, was treated for minor injuries, he said.

Neither driver's name had been released, Valenzuela said. Both drivers were wearing seat belts, and no drugs or alcohol were suspected. No charges were pending.

In another accident, two vehicles collided on I-70, just after the highway's intersection with I-15. A man and a woman heading east on I-70 collided with another vehicle, causing it to roll off the freeway, Valenzuela said.

One woman was thrown from the vehicle and died at the scene, he said. The man who was driving was pronounced dead at the hospital of multiple head injuries. The driver of the second vehicle had no serious injuries. Further details weren't immediately available, Valenzuela said.