California courts addressing product liability lawsuits utilize two alternative tests for assessing whether the product at issue contains a design defect.  The trial judge determines which test will apply, based on whether consumers will develop expectations about the product’s characteristics from their everyday use and experience.  If the product’s characteristics are outside the purview of an everyday consumer, then the judge will apply the risk-benefit test rather than allowing the jury to judge the product’s design based on their own experiences under the consumer expectation test.   The choice of the design defect test is often hotly disputed by the parties because the risk-benefit test requires the introduction of expert testimony before a jury can find a product’s design “defective.” 

The Ninth Circuit on March 20, 2017, affirmed that California’s risk-benefit test, and not the consumer expectations test, provides the proper standard for determining the existence of a design defect in product liability allegations regarding vehicle roof strength.  In Edwards v. Ford Motor Co., the plaintiffs claimed that their Ford Explorer’s roof lacked sufficient rigidity and presented an unreasonably dangerous condition.  The evidence in the case indicated that the vehicle’s roof experienced eight inches of vertical intrusion into the Explorer’s cabin during a multiple-rollover crash. The plaintiffs claimed the roof performed inadequately and caused blunt force injuries that killed the driver.  According to the plaintiffs, proper design of the truck would have resulted in less than three inches of roof crush under the circumstances of this crash. 

At trial, the plaintiffs sought to prove the Explorer was defective by arguing that it failed to meet consumer expectations.  Ford countered by moving to exclude evidence and argument related to the consumer expectation test.  The trial court grated Ford’s motion and instructed the jury exclusively on the risk-benefit test for the design defect claim.  Unlike the more permissive consumer expectation test - wherein a jury is allowed to use their own experiences in determining whether a product failed to meet a reasonable consumer’s expectation – the risk benefit tests takes a holistic view of the risks and benefits of the design of the product in question and requires expert testimony.  Following the trial court’s exclusion of the plaintiffs’ consumer expectation evidence and use of the consumer expectations jury instruction, the jury returned a defense verdict.

The 9th Circuit on appeal found that the lower court correctly instructed the jury on the risk-benefit test, noting the “lack of consumer expectations regarding the extent to which the Explorer’s roof would crush in a multiple rollover accident.”  The Court reasoned that vehicle operators simply do not have a sufficient understanding about vehicle roof strength from ordinary use of vehicles: “Drivers’ everyday experiences do not allow for the formulation of reasonable expectations as to the degree that a vehicle’s roof should crush during a rollover.”  That analysis requires insight from experts such as structural engineers.  Introduction of such evidence, in turn, renders the risk-benefit test for design defect liability to be necessary.

This ruling helps advance the developing principle in California that the risk-benefit test is the exclusive method for assessing defect in vehicle crashworthiness claims.  Because vehicles employ advanced technologies and multiple occupant protection devices, product liability crashworthiness claims must depend on expert analysis.  With increasingly complex vehicles incorporating multi-layered protection strategies, the everyday experience of product users often will not provide a sufficient basis for assessing whether a vehicle has a design defect in its crashworthiness systems.