One Louisiana teen has been charged with assault and another with saving the day: The first knocked a school bus driver unconscious and the second prevented the bus from crashing.

The 26-year-old female driver had stopped the bus Thursday afternoon to exchange words with a student who was unruly, said Baton Rouge Police Department spokesman Cpl. L'Jean McKneely.

The driver told authorities the 15-year-old boy then walked up behind her and punched her several times in the head, knocking her unconscious, McKneely said.

The bus started to move after the unconscious driver's hands and feet slipped off the wheel and brakes, said Keith Bromery, a spokesman for East Baton Rouge Parish schools. He said after the 15-year-old fled, the 14-year-old male student ran forward and stepped on the brake, put the bus in park and called 911.

The 15-year-old boy's mother later turned him in to police. He is charged with battery of a bus driver, second-degree battery and aggravated obstruction of a roadway. Authorities said they did not know if the teenager had an attorney. The Associated Press does not generally identify juveniles accused of crimes.

Local news media reported that school officials have suspended the 15-year-old pending an expulsion hearing, and that the 14-year-old was congratulated by transportation officials for trying to protect his fellow students and get medical help for the bus driver.

The bus driver was recovering at home after being treated at a hospital for moderate injuries, local news media reported.