R. Scott King, BSME ::::
Case Synopsis: Operator of a late model Ford vehicle was involved in a multi-vehicle incident wherein his vehicle reportedly accelerated suddenly and unexpectedly. Witnesses reported hearing the engine “roar” suddenly while the operator reported he could not slow the vehicle despite his insistence of firmly applying the brakes. Fortunately, no injuries were reported; however, there was substantial property damage, including four parked vehicles and a shopping cart corral.
Expert Analysis: Subject vehicle was equipped with two event data recorders (EDR) that were accessible using factory-approved and authorized equipment. One such data recorder captured data associated with the incident and provided engineers with approximately 25 seconds of pre-crash data. According to the data, the operator started the engine, applied the accelerator, shifted the automatic transmission from park to drive, than fully accelerated the vehicle. At no time, according to the data, did the operator apply the brakes thus suggesting operator error, not a mechanical malfunction, as a contributing factor; however, in the words of the late Paul Harvey, “And here now, the rest of the story”.
The incident vehicle was also equipped with a Brake/Transmission Shift Interlock (BTSI) mechanism, which, according to the National Highway Traffic Safety Administration, is effective at reducing reports of sudden acceleration incidents (SAI). Normally, the BTSI system requires brake pedal application prior to shifting. Testing on the incident vehicle revealed this system was inoperable. Thus, the operator was able to shift from park while depressing the accelerator pedal, and accelerating the engine.
Conclusion: Claims of sudden acceleration incidents (SAI) have existed for many years. Until recently, manufacturers had no way to determine if such incidents were the result of operator error or a mechanical malfunction, such as a cruise control or transmission failure. The EDR now has the potential to speak to this decades-old debate. In the instant case, the EDR established clearly that the incident was the result of pedal misapplication; however, the data and post-incident inspection also indicated clearly that the error was facilitated by a failure of the BTSI system.Categories: Case Studies