SAN DIEGO -- A motorist escaped injury Tuesday with the help of passers-by after her car veered off a Gateway-area road and into a canyon, where it burst into flames.

The driver, in her late 60s or early 70s, was heading up a hill on Ash Street when her older-model BMW sedan stalled and began rolling backward shortly before 9:30 a.m., according to the San Diego Fire-Rescue Department.

The vehicle jumped a curb near 38th Street, careened down a brushy slope, crashed to a stop and caught fire, SDFRD spokesman Maurice Luque said.

The driver managed to get out of the sedan and make her way back up the embankment with the aid of several witnesses, who helped direct her out of the way of the spreading flames, Luque said.

It took firefighters less than 10 minutes to extinguish the blaze, which blackened a roughly 90-square-foot area. No homes were threatened.

Investigators set the monetary loss of the car and its contents at $3,500.