The development of a modern transportation product requires that the safety of the product be considered at every stage of its life, from initial design to ultimate product disposal. Virtually all of the decisions that can positively effect product safety are made during the product design stage with most of the critical decisions being made early in the process. As a result, early incorporation of system safety into the design process has been shown repeatedly to result in safer products.
Incorporation of formal system safety programs into ground transportation vehicle design programs is comparatively recent. Historically, in both the automotive and the heavy goods vehicle industry, product safety has been provided through consistent over design of evolutionary system elements to ensure correct functioning under repeated exposure to worst case stresses. The degree of over design has been confirmed through a combination of experience with previous generation products, testing, and where warranted, through stress analysis techniques such as finite element analysis. As advanced technology, particularly computer control of an increasing number of on board systems, has been incorporated into new vehicle designs, traditional approaches to ensuring product safety are no longer adequate for all elements of vehicle design.
This paper discusses system safety as an applied methodology that, when incorporated into the design effort for vehicle components, feeds back to the design team an ongoing assessment of the relative risks of potential design alternatives. A discussion of the relationship of system safety to the overall safety surrounding vehicle use is provided. Specific discussions of some of the design approaches driven by the integration of electronic systems into vehicle design are given, as is a top level discussion of the way that system safety must be incorporated into the design team effort to be effective. Specific analysis techniques are presented and discussed at a summary level to impart an understanding of how the output of these analyses can be used to measure the risk of a specific design implementation and allow it to be controlled.
