Accident reconstruction research

Research / Rollovers And SUV

SUV's, Ford, Firestone, and Physics Versus Statistics

With charges of blame being spread around, each side of the issue seem to use statistical accident data to make a case. Statistics do have a place and in the right place are legitimate analytical tools. Statistics, however, unless the number of samples is extremely large, are lacking in many ways. Even then, unless all data uses the same baseline are subject to a very large number of potential probabilistic errors. For example, age, sex, size of a driver, load in the vehicle, air pressure, and condition of various vehicle components at a time of a crash, may have a great deal more to do with results than tire and vehicle design.

SUV's are not just other passenger cars. Weight, higher center of gravity, and a much stiffer suspension are but some elements which makes SUV's a much different vehicle than your average passenger car. The "physics" of SUV's are likely to have a great deal more to do with the cause of crashes than just tire design, or other simplistic elements drawn from statistical data.

There is a little, or no question, that tires played a part in the case of Ford's SUV crashes; there is even less doubt that the actual design and how it effects the physics, which simply means stability of the SUV.

It is time that when causes of crashes are investigated, presented to Congress, or discussed by the media, the finger pointing stops, statistics are put in their subservient place, and the relation between the vehicle physics and crashes becomes the focus of assessing the problem. When one examines the physics of a vehicle, integrating ALL components, including tires, suspension, and general design, then the causes of problems can be established and dealt with in an effective manner.

Dan Goor
XSCi
ARC Member, Colorado

Submitted June 30, 2001