Los Angeles Fire Department spokesman Brian Humphrey said Sunday that the toddler was properly restrained in a car seat when the sedan slammed into a pole on State Route 118 in Mission Hills.
He said the impact was so severe that rescuers spent more than hour cutting the car apart to get to the driver. She was pronounced dead at the scene. Her name and relationship to the child were not immediately released.
Humphrey said the boy was taken to a hospital in fair condition.
The California Highway Patrol shut several lanes to investigate, causing traffic in the San Fernando Valley to back up for miles.