The girl was in an argument with her father at about 5:15 p.m. on westbound Highway 80 east of Appian Way.
Her father, a 57-year-old San Pablo man, pulled over to the right shoulder and had slowed the car to about 10 mph when the girl jumped out, Maguire said.
She sustained several lacerations and was knocked unconscious when she landed.
Her father stopped and called for help. By the time emergency crews arrived, the girl had regained consciousness. She is expected to survive her injuries, but she was airlifted to Children's Hospital as a precaution, Maguire said.
Traffic was backed up for about an hour while crews responded to the incident.
The CHP does not expect to file charges or issue citations in connection with the incident, Maguire said.