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Optional Safety Devices: Delegating Product Design Responsibility to the Market

34 Pages Posted: 24 Feb 2014 Last revised: 1 May 2014

James A. Henderson Jr.

Cornell University - Law School

Aaron Twerski

Brooklyn Law School

Date Written: February 24, 2014


Early in the development of a robust system of products liability law, American courts delegated most of the responsibility for assuring the safety of product designs to the market. Except for designs that failed to perform their intended functions and thus should be said to be dangerously self-defeating, most courts rejected claims that products were legally defective because they could have been designed more safely. As long as the relevant risks were obvious or product sellers supplied adequate warnings of hidden risks, product purchasers, not courts, determined how much design safety was appropriate. And then came the products liability revolution. Spurred by the adoption of strict liability under § 402A of the Restatement (Second) of Torts, courts began in the 1970s to question, and then to reject, the idea that adequately-informed consumers always make sensible decisions regarding product design safety. Thus arrived a new era in American products liability in which courts began independently to review the reasonableness of manufacturers’ product design choices, thereby second-guessing decisions reached in the market. In fairly short order courts abolished the patent danger rule and opened their doors to a broad range of fault-based design defect claims.

Perhaps the most significant exception to the general pattern of courts overriding markets by engaging in broad product design review — a controversial subject upon which this essay focuses — concerns optional safety devices with respect to which purchasers, not courts, often make controlling decisions. The issue of when courts should delegate responsibility for product design safety is complex. What has been lacking to date is a structured approach to this issue. This essay, for the first time, pulls together the various strands of rationale offered by the courts into a coherent approach, concluding with a proposed Restatement section with comments. Work remains to be done in applying the suggested approach to future cases. The authors believe that this essay provides an important starting point for further development.

Suggested Citation

Henderson, James A. and Twerski, Aaron, Optional Safety Devices: Delegating Product Design Responsibility to the Market (February 24, 2014). Arizona State Law Journal, Vol. 45, p. 1399; Brooklyn Law School, Legal Studies Paper No. 298. Available at SSRN:

James A. Henderson Jr. (Contact Author)

Cornell University - Law School ( email )

Myron Taylor Hall
Cornell University
Ithaca,, NY 14853-4901
United States

Aaron D. Twerski

Brooklyn Law School ( email )

250 Joralemon Street
Brooklyn, NY 11201
United States

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