Michael Anthony Meza, 32, of Pomona was found dead in a car toward the bottom of the White Avenue exit.
California Highway Patrol officers discovered Meza at about 12:30 a.m when they investigated a car parked on the side of the roadway, authorities said.
The Los Angeles County Fire Department pronounced Meza dead at the scene with multiple gun shot wounds to his upper torso.
A rear passenger window of the vehicle was shot out, according to police.
Police officers have not determined where the shooting occurred. They have also not said whether the man was the driver or a passenger of the car.
A motive for the shooting is unknown and police have no suspect leads at this time.
Anyone with information on this incident can call detectives at 909-620-2095.
Pomona police officers did not return requests for comment.