Automotive Transmission Malfunction Blamed For Parking Lot Collision

This case involves the driver of a mid-size SUV. The driver was parked in the parking lot of a large shopping plaza. After a period of time, the driver decided to turn off the vehicle. When he turned the key to the “off” position, the car immediately began to roll back into oncoming traffic. The driver tried to stop the vehicle by jamming the transmission into “park,” however it did not stop. The driver crashed into another car and both parties suffered injuries. An expert in automotive transmissions was sought to opine on whether the transmission to stop the vehicle malfunctioned.

Question(s) For Expert Witness

1. Please briefly describe your experience with transmission controls.

2. Have you specifically worked with transmission defects in similar vehicles?

Expert Witness Response E-024234

I have 30 years of experience in the automotive industry, starting as a mechanic and advancing (with appropriate education) to a high-level international troubleshooter in manufacturing problems. I hold master's and doctoral degrees in ergonomics, from an engineering perspective, and I have spent 10 years teaching automotive engineering, including modules on drivetrain and automatic transmissions from a design viewpoint.

My first impression is that the driver of the vehicle may have contributed to this situation, but I'd have to know a lot more about it to reach any positive conclusions.The simple reason why the vehicle could not be put into "park" is likely that the engine was shut off, so there was no hydraulic pressure within the transmission to move the internal components. There was also no power to the transmission controls to move the necessary solenoids to effect the shift. Because of the design of the park pawl, it's next to impossible to shift into park while the vehicle is rolling anyway. Also, without the engine running, there is no engine vacuum to operate the power brake booster. In this condition, it would have been difficult to stop the vehicle with his foot while properly seated and able to apply full leg muscle force.