An investigation into a tour bus crash last week on Interstate 80 just north of Fairfield revealed a combination of driver error and partial brake failure, according to the California Highway Patrol on Wednesday.
The crash took place May 23 after the driver of the United Coach Tours bus, 38-year-old Yunzho Ma, swerved from the fast lane of the freeway across the traffic lanes to the right and off the roadway, just east of the North Texas Street overcrossing, according to the CHP.
More than a dozen people reported minor to moderate injuries after the bus shot across the shoulder and through a barbed wire fence before finally stopping on a road that boarders the freeway.
“It’s a two-fold situation,” said CHP Officer Rick Weaver, the crash’s investigating officer.
Ma told officers at the scene that she had been having problems with the bus’ brakes prior to driving off the roadway, according to the CHP.
Following the accident, Weaver said the bus was put up on blocks and a complete vehicle inspection was performed by the CHP. According to Weaver, investigators found that the bus’ right-rear brake pad had been worn very thin.
“The bus had not been properly maintained,” Weaver said, noting that that was something the company was responsible for. “The driver doing the check out would have no way of knowing that without taking off the wheels.”
Still, Weaver said the bus had some braking power, and the failure alone was not responsible for the crash.
“I think she probably could have pulled safely to the shoulder,” Weaver said before adding that nothing was in the path of the bus to warrant the driver to perform such “drastic” maneuver.
However, because of this discovery, Weaver said the CHP is calling for a full inspection of the South San Francisco terminal where the tour bus is based.Authorities added that Ma was also exceeding the posted speed limit, and is thought to have been driving approximately 70 mph at the time of the crash.Weaver said that although the driver has been determined to be at fault, it has not yet been determined if she will be cited.