Design defects.

AuthorOwen, David G.
PositionSymposium: A Tribute to Professor David Fischer

    The concept of design defectiveness lies at the heart of products liability law. A product's design concept predetermines the extent to which use of the product will result in human injury, and modern products liability law rests fundamentally on the premise that manufacturers are fairly held to answer in the courts for the basic safety of their products' designs. Yet judicial oversight of a manufacturer's design choices is a relatively new phenomenon. Design defect claims under any theory of liability were infrequently entertained by courts early in the twentieth century, (1) and only in recent decades have courts begun to adjudicate with any frequency the reasonableness of product designs in accident litigation.

    Finding an acceptable definition for what constitutes a "defective" design is a difficult task. Elusive as an elf, the true meaning of "design defect" has largely escaped capture by court or commentator, and the search therefor leads inexorably to consternation and confusion. The quest for understanding design defectiveness perennially vexes courts (2) and accomplished products liability lawyers (3) attempting to unravel design defect problems; delights law clerks, (4) young associates, (5) and law students (6) furnishing them with an occasion to display their erudition; and provides fertile grist for law professors (7) aspiring for the renown that accompanies discovery of the key to any riddle wrapped in a mystery inside an enigma. (8)

    Just as strict liability in tort is the dominant liability theory in major products liability litigation, design defectiveness is the dominant claim in most major products liability cases. (9) Manufacturer design determinations involve a multitude of safety-related choices, including decisions on the types and strengths of raw materials and component parts, the manner in which such materials and parts are combined, whether safety devices will be included, and the overall product concept. A frequent claim of design defectiveness is the absence of some type of adequate safety device, such as a sufficient housing surrounding a power lawnmower, (10) a mechanical guard or electrical interlock cut-off device on a dangerous machine, (11) or a "safety" on a gun. (12) Much automotive products liability litigation challenges the design of motor vehicles, including the extent to which their designs are sufficiently "crashworthy" to provide their occupants adequate protection in the event of a crash. (13) In addition to such typical design danger claims, numerous other forms of design hazards may give rise to claims of defectiveness--such as allergenic latex gloves, fabrics not treated with flame-retardant chemicals, drain cleaners comprised of unnecessarily caustic chemicals, products whose moving parts are made of metal too soft to last throughout the product's useful life, tampons that are too absorbent, coffee that is too hot, raw asbestos comprised of toxic fibers, and tell-tale mechanical heart valves that emit excessive noise. (14)

    In the early stages of modern products liability law, courts commonly viewed the notion of product "defectiveness" as embracing a single principle applicable to any type of case. (15) As products liability law has matured, (16) however, most courts (17) and commentators (18) have come to understand that meaningful evaluation of the acceptability of a product's dangers logically turns on considerations that vary contextually depending upon whether the problem was one of manufacture, design, or the absence of sufficient warning. (19) Early in the evolution of products liability law, observers recognized that determining how and why a design danger should or should not be characterized as "defective" was at once the most important and baffling problem in this entire field of law. (20) For this reason, much of the search for a general definition of "product defect" was in fact a search for the meaning of defectiveness in design, (21) as explored below.

    Determining how to evaluate the acceptability or defectiveness of a product's design is difficult in part because a product's design is the essence of what the manufacturer decides to make and sell. A manufacturing defect is truly a mistake, one that results from some fault in the production process whereby a particular product deviates from the manufacturer's own "blueprint" specifications of the intended and correct design. Quite to the contrary, a charge that a product is defective in design challenges those very specifications on the ground that the design engineers, in their conceptual rendition of the product, failed to take safety into adequate account. Consequently, challenging a product's design challenges the decision of the manufacturer's engineers and managers to develop and sell a product containing a particular type and level of danger. Thus, unlike a manufacturing defect claim, which implicates merely a single product unit, a design defect claim challenges the integrity of the entire product line and so pierces to the very core of the manufacturer's enterprise. For this reason, design defect claims are of greatest concern to manufacturers, since a judicial declaration that the design of a particular product is "defective" condemns the entire product line.

    Judicial evaluations of manufacturer design decisions encounter other difficulties, too. Far more than in manufacturing and warning defect cases, design cases require courts to second-guess a manufacturer's analyses of consumer market preferences. Some commentators have challenged the propriety of courts displacing multi-faceted engineering and managerial determinations of this type with judicial fiats rendered in the litigation arena. (22) Be that as it may, courts around the nation have come to adjudicate the sufficiency of product designs on a regular basis.

    This Article examines the tests of design defectiveness developed by the courts, particularly in applying the doctrine of Restatement (Second) of Torts [section] 402A. The Third Restatement's definition of design defectiveness is examined in Part VIII. (23)


    Manufacturers and other sellers (24) are subject to liability for defective design under each of the major theories of liability. Thus, as is true with respect to other types of defects, product suppliers are subject to liability in negligence, for negligently making and selling products that are defectively designed; (25) in implied warranty, for selling products that are not fit for their ordinary purposes, and hence "unmerchantable," because they are defectively designed; (26) and in strict liability in tort for simply selling products that are defective in design. (27)

    Regardless of the theory of liability, whether a design is "defective" is typically the central issue in litigation associated with a product's design. Indeed, the Products Liability Restatement proposes that liability in such cases be grounded solely on the notion of product defect rather than on traditional theories of liability such as negligence and strict liability in tort. (28) Strict liability in tort, of course, is defined principally in terms of a product's "defectiveness." (29) Yet proof of a defect in a product's design is just as important in cases brought in negligence inasmuch as a manufacturer hardly can be at fault for selling a product with a safe design, a design that is not defective. (30) Moreover, in the great majority of states, and even in most cases brought in the Empire State, (31) proving that a product design is dangerously unmerchantable under UCC [section] 2-314 amounts to precisely the same thing as proving that the product is "defective" (or "unreasonably dangerous") under Restatement (Second) of Torts [section] 402A. (32)

    In considering the concept of design defectiveness, it is crucial to remember that a manufacturer's liability for harm from a product's design characteristics, even if labeled "strict," is not absolute. As the strict manufacturer liability principles of Greenman v. Yuba Power Products, Inc. (33) and Restatement (Second) of Torts [section] 402A spread across the nation in the 1960s and 1970s, (34) courts and commentators searched mightily for standards or "tests" of liability that would stop liability well short of absolute. (35) Although early test formulations generally failed to distinguish between the various forms of defect, most of the early cases struggling with the meaning of defectiveness involved dangers in design. (36) Consequently, the evolution of early strict liability tests generally involved a search for appropriate methods for separating product designs that were adequately safe from those that were not.

    All courts judge the adequacy of a product's design upon one of two basic standards, or some combination thereof: (1) the "consumer expectations" test--whether the design meets the safety expectations of users and consumers, and/or (2) the "risk-utility" test--whether the safety benefits of designing away a foreseeable danger exceed the resulting costs. The following section examines [section] 402A's original test, the consumer expectations test. The fundamentals of the risk-utility test are then considered in Part IV, which explores the appropriate factors weighed in a risk-utility balance. Part V next inquires into the critical role of feasible design alternatives in risk-utility decision-making. The blending by some courts of the consumer expectations and risk-utility tests is investigated in Part VI; the Wade--Keeton prudent-seller hind sight test, based on constructive knowledge of a product's design dangers, is explored in Part VII; and the Products Liability Restatement's treatment of the design defect concept is examined in Part VIII.


    The consumer expectations test was the first standard for evaluating design defectiveness, and it remains a persistent, if embattled, liability test in at...

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