Understanding Sudden Toyota Acceleration

As a materials and manufacturing engineer with decades of experience analyzing manufactured product failure and as a Toyota vehicle owner, I am saddened by the lack of experience and knowledge shared with Congress and the public on the problem of sudden acceleration.

When products fail due to systemic design, materials, or manufacturing flaws, large and statistically significant levels of problems emerge fairly quickly. This is definitely not the case with the Toyota problem. With many millions of Toyota models driven even more millions of miles, had there been an inherent flaw in materials or manufacturing design, we would have seen thousands of instances of sudden acceleration. Literally, it would have been practically a daily event happening across the country on many Toyota models. But in fact, just over 1,000 Toyota and Lexus owners have reported since 2001 that their vehicles suddenly sped up on their own. This is a tiny and tiny percentage of Toyotas.

This rare problem of a runaway car is not analogous to a severe case of bacterial contamination of a major food product that causes many thousands of cases of food poisoning in a relatively short period of time. It is even more difficult to find the cause of.

Understanding this nature of the defects also means that the supposed solutions to replace the floor mats and accelerator pedals are sheer nonsense. In fact, I was not surprised to read today that there have already been cases of sudden acceleration in cars that had received fixes from Toyota. More than 60 Toyota owners have complained to the National Highway Traffic Safety Administration about the cars already repaired under Toyota’s two major recalls, saying they are not repaired and their throttles may still get out of control.

While the agony and suffering of sudden acceleration accidents and deaths is acknowledged, the statistically rare occurrences of this problem also need to be appreciated. Only in this way is it possible to understand that the final explanation – and the solution – of the sudden acceleration problem will be a failure or non-systemic defect in a critical component. In other words, a random defect in a material or some unusual and rare 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 that are 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 rare defect in a raw material or manufacturing process that would not show up in routine quality control testing of raw materials or components. The fact that so many different Toyota models over many years have been found to be defective means the likelihood that a particular problem component will be made in a specific factory that has been used for quite some time. In addition, the defect, obviously, does not usually affect the behavior of the vehicle, but only manifests itself in some rare conditions, not yet determined.

Rita Taylor of Fort Worth, Texas experienced uncontrolled acceleration, took her car to a Toyota dealership and had the floor mats removed. A few months later he had another terrifying escape episode. The same goes for Eric Weiss in California, who also had a second episode months after the first and after removing the floor mats. Others who have not died and continue to use their Toyotas have also had repeat events. Therefore, perfectly normal vehicle performance is possible between leak events.

Make no mistake, the precise cause of such a sporadic event is incredibly difficult to pin down and even harder to remedy. Extremely intensive and expensive research is required. It’s the classic needle-in-a-haystack problem.

If my thinking is correct, then it is insane to believe that replacing the floor mats or accelerator pedals can solve the problem of sudden acceleration. However, there is one aspect of the sudden acceleration problem that is also crystal clear and in some ways even more aggravating than the acceleration problem. This is the absence of an override system that absolutely prevents fuel from being fed to the engine when the brakes are applied while a car is accelerating. It is gratifying that the federal government is seriously considering requiring such an override system on all vehicles. An effective override system could, in the long run, be a quicker and more cost-effective solution than chasing the defect, especially for the modernization of many millions of vehicles.

Alternatively, finding the cause of the sudden acceleration problem requires a standard fault analysis methodology, that is, obtaining absolutely all Toyota vehicles that have experienced sudden acceleration. Then, meticulously examine through microscopic and other analyzes and test all critical components of the electronic system (called by Toyota the Electronic Throttle Control System with intelligence). Think of it as an autopsy.

This does not appear to have been done. In contrast, the firm contracted by Toyota tested various ordinary vehicles and components. One of the lead authors of the Exponent report said that they did not examine any vehicle or component that had the involuntary accelerations. This is meaningless if the defect is rare and therefore your finding that there was nothing wrong was meaningless. Worse still, it was a deception and a distraction.