Two men involved in a crash Thursday morning on Highway 99 were killed while trying to help the driver of the other vehicle, the California Highway Patrol said.

They were standing in front of the other driver's overturned car when a passing car ran into it and threw them into the air, the CHP said.

At approximately 2 a.m. Thursday, a Honda and a Toyota crashed on northbound Highway 99 south of Mack Road, CHP Officer Michael Bradley. Two of the four passengers in the Honda got out of their car to help the driver of the Toyota out of his car, which was overturned in the far left lane, Bradley said.

As the trio stood in front of the Toyota, a Chevrolet Tahoe also driving northbound struck the overturned Toyota, which in turn struck the three people in front of it. The two people who had gotten out of the Honda were propelled into the southbound lane and killed.

They were identified by the Sacramento County Coroner's Office as Eddie Thammavong, 21, and Ricky Laosouvanh, 22.

The driver of the Toyota who was also hit was taken to the hospital with serious injuries, Bradley said.

Bradley said that alcohol and drugs were not a factor in the accident.

Traffic on northbound Highway 99 was initially blocked, but all lanes were subsequently opened, Bradley said.