A motorcyclist possibly driving under the influence nearly died in a collision with a sedan in El Segundo, police said Monday.

The 7:50 p.m. crash Sunday shut down the westbound lanes of Rosecrans Avenue near Pacific Avenue for several hours for an investigation.

Witnesses told police the 48-year-old motorcyclist was headed north on Sepulveda Boulevard and then turned west on Rosecrans. He crashed into the rear of the sedan, which was stopped for a red light at Pacific.

The motorcyclist, whom police say was possibly under the influence, was described as having substantial life-threatening injuries.

The driver of the car was not hurt.