FONTANA, Calif. — Two adults and two children were killed in a highway crash outside of Los Angeles on Friday after one car smashed into another vehicle that had overheated, the California Highway Patrol said.

The Honda sedan that overheated had pulled to over to the side of Interstate 10 in Fontana, and one of the women inside called her husband for help, said Officer Jesus Garcia of the California Highway Patrol.

By the time he arrived, his wife was dead.

She and two children who were inside the Honda were killed when a Nissan Frontier veered off the highway and slammed into the Honda and a Toyota Tacoma that had stopped to help, Garcia said.

The male driver of the Tacoma also was killed.

The Nissan’s driver and the driver of the Honda were taken to a hospital.

It’s unclear why the driver of the Nissan veered off the highway, but that there were no skid marks before the impact, Garcia said.

He said the husband and son of the woman killed arrived at the scene shortly after the crash and were inconsolable.

“All you can do is try to keep them calm and not let anybody see the body as it lays,” Garcia said, adding that officers were able to cover the victims with blankets before family arrived.

Traffic on eastbound Interstate 10 was backed up more than 5 miles, with two lanes remaining closed throughout the afternoon.