As a materials and manufacturing engineer with decades of experience with failure analysis of manufactured products, and as an owner of a Toyota vehicle, I am saddened by the lack of expertise and insight shared with Congress and the public about the sudden acceleration problem.
When products fail due to a systemic design, materials or manufacturing flaw, large and statistically significant levels of problems emerge fairly rapidly. This is definitely not the case with the Toyota problem. With many millions of Toyota models on which even more millions of miles have been driven, if there had been an inherent materials or manufacturing design defect, then we would have seen untold thousands of cases of sudden acceleration. It literally would have been virtually a daily event happening all over the country in many Toyota models. But, in fact, little more than 1,000 Toyota and Lexus owners have reported since 2001 that their vehicles suddenly accelerated on their own. This is a tiny, minuscule percentage of Toyotas.
This infrequent runaway car problem is not analogous to a serious case of bacterial contamination of a major food product causing many thousands of cases of food poisoning in a relatively short period. It is even more difficult to find the cause of.
Understanding this nature of defects also means that the so-called solutions of replacing floor mats and gas pedals are sheer nonsense. Indeed, it did not surprise me to read today that there have already been cases of sudden acceleration in cars that had received fixes by Toyota. More than 60 Toyota owners have complained to the National Highway Traffic Safety Administration about cars already repaired under the two major Toyota recalls, saying they aren't fixed and their throttles can still race out of control.
While recognizing the agony and suffering of sudden acceleration accidents and deaths it is also necessary to appreciate the statistically rare occurrences of this problem. Only by doing so is it possible to understand that the ultimate explanation and solution to the sudden acceleration problem will be a non-systemic flaw or defect in a critical component. In other words, either a random defect in a material or some unusual and infrequent deviation in a manufacturing process of some critical component. Only such a situation can logically explain so few sudden acceleration problems in so many millions of cars being operated for many more millions of hours and miles.
In my professional opinion, the likely scenario is a defect in a semiconductor chip used in the electronic control system. A defect that was caused by some infrequent flaw in a raw material or manufacturing process that would not show up in routine quality control testing of raw materials or components. That so many different Toyota models over many years have been found defective signifies the likelihood of a particular problem component made in a specific factory that has been used for quite a while. Moreover, the defect obviously does not ordinarily impair vehicle performance but only manifests itself under some infrequent conditions, as yet undetermined.