Soule v. General Motors Corp., 8 Cal. 4th 548, 34 Cal. Rptr. 2d 607, 882 P.2d 298 (Cal. 1994)
Soule v. General Motors is a cornerstone California products-liability decision that recalibrates the relationship between two Barker v.
In a crashworthiness design-defect case involving complex vehicle systems and technical causation, may the jury be instructed on the consumer-expectations test, or is the plaintiff limited to proving defect under the risk–benefit test supported by expert evidence?
Under Barker v. Lull Engineering Co., a design defect may be proven by either: (1) the consumer-expectations test, which asks whether the product failed to perform as safely as an ordinary consumer would expect when used in an intended or reasonably foreseeable manner; or (2) the risk–benefit test, under which, once the plaintiff proves the design was a substantial factor in causing injury, the burden shifts to the manufacturer to prove that, on balance, the design's benefits outweigh its inherent risks. Soule limits the consumer-expectations test to cases where the product's performance in the circumstances is within the common understanding of ordinary consumers; when design choices and their safety implications are technical, complex, and beyond common experience—as is often true in crashworthiness claims—defect must be evaluated under the risk–benefit test with expert evidence. Crashworthiness (enhanced-injury) doctrine permits recovery for design defects that increase or enhance injuries in a foreseeable accident, even if the defect did not cause the accident itself, subject to ordinary causation principles and comparative fault defenses.
The consumer-expectations instruction was improper in this complex crashworthiness design-defect case and its use was prejudicial. The judgment based on that instruction was reversed and the matter remanded for a new trial limited to proper risk–benefit evaluation.
Soule is the leading California authority confining the consumer-expectations test to truly lay-understandable failures and directing complex crashworthiness design claims to the risk–benefit test. It shapes pleading strategy, expert proof, and especially jury instructions: trial courts must decide as a matter of law whether consumer expectations meaningfully apply to the particular design-performance issue. The case also integrates crashworthiness doctrine within Barker's framework and reinforces burden shifting under risk–benefit once causation is shown. For law students, Soule illustrates the interaction of doctrine (design defect and enhanced injury), evidence (need for expert testimony), and procedure (instructional error and prejudice) in products liability.