One teenager is dead and another was seriously injured after a tractor-trailer crashed into the rear of a sedan that was stopped on I-75 in Cobb County, causing several hours of delays Sunday night.

Cobb police said a 2003 Toyota Camry was traveling southbound when it stopped in the fourth lane from the left just south of Delk Road shortly after 8:30 p.m., according to a news release. Police do not know why the vehicle stopped.

Approaching in the same lane was a tractor-trailer, the news release states. The truck crashed into the Toyota, pushing it across two lanes.

The driver and passenger, both 18, were ejected from the Camry, police said.

The driver was taken to a hospital with serious injuries, and the passenger, who has not been identified, died at the scene, police said. The driver of the tractor-trailer was taken to a hospital with minor injuries.

Investigators believe a mechanical issue may have contributed to the crash, according to the release.

Anyone with information is asked to call 770-499-3987.