The accident occurred around 8:30 a.m. near East San Bernardino and North Towne avenues in Pomona, according to Los Angeles County Fire officials.
Police said a 22-year-old Pomona man riding in the car died on the scene. The car’s 31-year-old female driver was seriously injured.
There were no passengers on the bus at the time of the accident, officials said.
The North Towne Avenue offramp of the eastbound San Bernardino (10) Freeway was closed for an investigation.