A dump truck hit a row of parked cars near Broadway and Divisadero Tuesday in Pacific Heights.

Media: Tyson Winter

Three people suffered minor injuries and at least nine vehicles were damaged when a runaway dump truck, without its driver, barreled down a street in San Francisco’s Pacific Heights neighborhood Tuesday, police said.

The commercial dump truck slammed into parked cars as it careened down Divisadero Street between Broadway and Vallejo Street around 2:45 p.m., said Officer Robert Rueca, a police spokesman. It also hit at least three moving cars, injuring the motorists, Rueca said.

Police were investigating the cause, but Rueca said, “It doesn’t appear to be intentional. The runaway could be mechanical or could be human error.”

The driver was cooperating with investigators, police said.

In an interview, the driver said he had been cleaning up construction debris at a home on Divisadero and turned around to see his truck rolling forward down the street.

The driver, who declined to give his name, said he had placed blocks under the front tires and put the truck in gear, and didn’t know how it had rolled free.

Tyson Winter, who witnessed the incident, posted video to Twitter showing damaged cars surrounded by debris. Vehicles had smashed windows, crumpled bumpers and other damage.

Donna Byrum, who lives on Broderick Street a block west of Divisadero, said as she viewed the damage, “I’ve lived here for 30 years and I’ve never seen anything like this happen.”

Annie Ma and Evan Sernoffsky are San Francisco Chronicle staff writers. Email: ama@sfchronicle.com, esernoffsky@sfchronicle.com Twitter: @anniema15 @EvanSernoffsky