Automotive safety expert witness advises on stuck car accelerator

An automotive safety expert witness with a background in mechanical and automotive engineering discusses automobile accidents caused by stuck accelerators. This case involves a man and his son who were killed and several of their family members were permanently injured when their rental car was hit from behind by another vehicle. The driver of the offending vehicle, who was returning from a family function with his pregnant wife and other relatives, said the car suddenly accelerated as he was exiting the highway. The brakes did not work. The vehicle was estimated to be traveling 90-mph when it impacted the victims’ vehicle, which was stopped at the end of an exit ramp.

The driver was convicted of vehicular homicide and sentenced to prison. It wasn’t until after vehicles made by the same manufacturer were being recalled for similar acceleration problems that the driver won reversal of his conviction under the industry-specific Lemon Laws. The victims then sued the auto manufacturer for wrongful death, design defect and failure to warn, among other claims.

Question(s) For Expert Witness

1. What was the chief cause of this accident?

2. Were there safer designs that could have been used at the time the vehicle was built?

Expert Witness Response

The accident was primarily caused by a defect in pulleys in the vehicle’s cruise control systems. A cable runs from the gas pedal through two plastic pulleys connecting the cable to the cruise control assembly. The cruise control assembly is encased in plastic, which, when exposed to heat causes the pulleys to stick. This causes the throttle to remain open, causing the vehicle to accelerate. Additionally, due to their design, these pulleys and their bracket warp over time, causing misalignment of the cable. This exacerbates the heat-related throttle problem.

The defect could have been remedied by using one of three better designs: metal pulleys instead of plastic pulleys, separate cables for the cruise control and throttle, instead of pulleys to relay one cable, and moving the throttle pulley assembly higher and further from heat sources inside the engine compartment.

The expert is a consulting engineer in the automotive safety field. He has a master’s degree in mechanical engineering and previously worked as an engineer and vehicle designer at Big 3 auto makers.