The screams of women and children didn't cause a 100-year-old driver to stop as he backed his large powder blue Cadillac onto a sidewalk across from an elementary school and hit 11 people, including nine children.

So people began pounding on his windows screaming for him to stop, a witness said.

Alma Solache said she was buying her children an afterschool snack just before the accident outside a south Los Angeles school.

"He was not paying attention," said Solache, 24, adding that it was at least two or three seconds before the vehicle halted and people began pulling children out from beneath the car.

Detective John Meneses told the Los Angeles Times that two victims remained hospitalised in stable condition today (NZ time).

Children's backpacks, shoes, candy and loose change were strewn about the scene behind a discount grocery store across from Main Street Elementary.

Police said the driver, Preston Carter, was being very co-operative and drugs or alcohol were not a factor in the crash.

Carter talked to television reporters after the crash some five miles southwest of downtown Los Angeles. He said he has a driver's license and will be 101 years old September 5.

"My brakes failed. It was out of control," Carter told KCAL-TV.

Asked about hitting the children, Preston said: "You know I'm sorry about that. I wouldn't do that for nothing on earth. My sympathies for them."

Carter was pulling out of the grocery store parking lot, but instead of backing into the street, he backed onto the sidewalk, police Capt. George Rodriguez said.

"I think it was a miscalculation on his part. The gentleman is elderly," Rodriguez said. "Obviously he is going to have some impairment on his decision making."

In 2003, an 86-year-old man plowed into an open-air street market in Santa Monica, California. Ten people were killed and 63 injured.

The US National Transportation Safety Board found the probable cause of that accident was "unintended acceleration" when George Weller stepped on the gas pedal instead of the brake, and then panicked and continued on through the crowd.

A criminal court jury, however, convicted Weller of 10 counts of felony vehicular manslaughter with gross negligence, not buying the defense argument that he was simply a befuddled old man.

According to California's Department of Motor Vehicles, people over age 70 must renew their driver's license in person, rather than via the Internet or by mail. Older drivers can also be required to take a supplemental driving test if they fail a vision exam, or if a police officer, a physician, or a family member raises questions about their ability to drive.

Rodriguez said the collision was being investigated as an accident, and Carter was not under arrest. He has a valid driver's license, Rodriguez said.

- AP