SW Legal studies in Business

Expert Testimony Must Be Based on Accepted Science, Not Conjecture

South Carolina high court reversed a verdict against an automobile company in a sudden acceleration case. The expert testimony about electromagnetic interference that supposedly caused the problem is not based on credible science and should have been excluded at trial.

Topic Torts
Key Words

Product Liability; Evidence; Expert Witness

C A S E   S U M M A R Y

Sonya Watson was driving a 1995 Ford Explorer with three passengers. She stated that she lost control of the vehicle due to sudden acceleration. The car went off the road and rolled, leaving her quadriplegic and killing a passenger. An electrical engineer testified that, in his opinion, the problem was caused by electromagnetic interference (EMI), by which electromagnetic radiation interferes with electric circuits, including the cruise control. He believed that EMI interfered with the electronic controls on the car, causing the cruise control to stay on. The problem could have been prevented by an alternative design in the electrical system. Ford responded that there was no scientific basis for the EMI theory and that tests on that issue have been negative. The jury ruled for the plaintiffs, awarding $18 million in compensatory damages. Ford appealed.


Reversed. The testimony by the electrical engineer regarding electromagnetic interference (EMI) and its effect on the vehicle's cruise control system was not sufficiently reliable to be admissible. The witness had no experience with automobile industry and no experience with cruise control systems. His theory had not been peer reviewed. He had never published papers on his theory or tested his theory. He could not determine where the EMI originated or what part of the system it affected. The expert testified that the alleged EMI malfunction could not be replicated in a testing environment. The documentation supporting this theory was not valid as the theory had been generally rejected in the scientific community. The witness's background in electrical engineering involved massive generators having entirely different electrical wiring systems and different voltage levels than vehicle, and the witness had no experience in automobile industry and had never studied cruise control systems or designed any component of a cruise control system. The trial court should not have allowed the jury to consider such testimony.

Citation Watson v. Ford Motor Co., ---S.E.2d--- (2010 WL 916109, Sup. Ct., S.C., 2010)

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