WASHINGTON, D.C. — School buses and other heavy vehicles should be equipped with technology to prevent unintended acceleration, the National Transportation Safety Board (NTSB) concluded in a report adopted in early September.

The agency said that a brake transmission shift interlock device, which requires the driver to apply the brakes to shift out of park, would have prevented a 2007 school bus loading zone crash in Falls Township, Pa., that injured 20 students. The bus suddenly accelerated at a high school, struck several students and then crashed into a retaining wall.

In its investigation of that accident, NTSB determined that the probable cause was a pedal misapplication by the driver. Pedal misapplication occurs when a driver depresses the accelerator instead of, or in addition to, the brake pedal.

Contributing to the occurrence of pedal misapplication in the Falls Township accident was the driver’s unfamiliarity with the school bus, NTSB said. It was a substitute bus, and the pedals were different from what the veteran driver was used to.

Now NTSB has called on the National Highway Traffic Safety Administration (NHTSA) to require brake transmission shift interlock devices in heavy vehicles susceptible to pedal misapplication. The board also recommended that NHTSA conduct an analysis of pedal configurations in heavy vehicles and study the effect of pedal design on the driving task.

Additionally, NTSB recommended that the National Association of State Directors of Pupil Transportation Services and the National Association for Pupil Transportation advise their members of the dangers of pedal misapplication and to consider driver refresher training and suggested mitigation strategies.

Brad Barker, shop supervisor at Park City (Utah) School District, agrees with the recommendation to require brake transmission shift interlock devices. As a member of the National Congress on School Transportation’s subcommittee for school bus specifications for 2010, Barker proposed that the devices be mandatory on all buses equipped with air brakes.

The committee voted against the proposal. Barker said the dominating feeling was that although it’s a good idea, it should be an option. But the NTSB findings seem to support his case.

“I feel that such a proposal, if passed, would enhance the safety of every school bus equipped with air brakes and help prevent such accidents as [the Falls Township crash],” Barker said.

NTSB held a public meeting Sept. 1 on its special investigative report on pedal misapplication, which also covers the fatal 2005 school bus crash in Liberty, Mo. The driver in that accident lost control of her bus and hit two vehicles. Two motorists died, and at least 23 students were injured. The driver reportedly told officials that she could not stop the bus.

The NTSB investigated and determined that the probable cause of the accident was a pedal misapplication by the school bus driver.

In addition to brake transmission shift interlock devices, the NTSB’s report on pedal misapplication covers event data recorders. The agency reiterated and reclassified two 1999 recommendations to NHTSA to require event data recorders on school buses and motorcoaches, and for NHTSA to work with other government agencies and industry to develop standards for on-board recording of bus crash data.

At press time, a synopsis of the report was available online at www.ntsb.gov under “Board Meetings.” The full report was scheduled to be available within several weeks of the Sept. 1 meeting, the NTSB said.