Toyota’s troubles with reported incidents of unintended acceleration, and its ongoing recall of some of its vehicles, have been a staple of news reports for a few weeks now. But there is an interesting article in today’s edition of the Washington Post that talks about how the engineering challenge that Toyota faces is manifested in an even more difficult communications and public relations problem. (That Toyota has not handled the problem particularly well is a different issue.) Some of the problems that have been reported, as the article points out, may well have been due to operator error — what systems support people sometimes call PEBKAC (Problems Exists Between Keyboard And Chair). But given the number of reports, it seems plausible, at least, that there is some more fundamental problem.
In essence, a significant part of the problem stems from the very considerable complexity of a modern automobile. Now, I am not an automotive engineer, but I do have some technical background; and the last car I drove regularly that I was reasonably confident that I understood was a 1967 Volkswagen Beetle. Contemporary cars have substituted electronically-controlled fuel injection, engine timing, throttles, power steering, and lots more for the simple mechanical devices that I sort of understood. These vehicles contain dozens of microprocessors, each running thousands of lines of software; a typical modern car contains on the order of 20,000 distinct parts. That all adds up to a lot of places where things can go wrong.
The process of identifying and fixing a car problem today has become like the process of diagnosing other complex systems: the body, in medicine, or a piece of software. The first challenge is to be able to make the problem occur:
The only way to credibly figure out why something fails is to attempt to duplicate the failure under observable conditions. This is the engineering method.
Even getting to this stage can be very difficult. Defects may manifest themselves only under specific and unusual circumstances, or may depend on what software engineers call “race conditions”: variations in the precise timing of a series of events. Realistically, no matter how thoroughly a system may be tested, it is almost impossible to ensure that no such problems remain:
If you put a lot of parts together to form a complex electromechanical machine and make it talk to itself via software, it can behave, sometimes, in ways you cannot anticipate. It can fail for reasons you cannot anticipate.
Anyone who has used a personal computer is familiar with the problem. It is the reason, for example, that, years after the software was initially released, Microsoft is still fixing bugs in Windows XP.
Toyota has not helped matters by some of its responses to the problem. It has insisted from the beginning that the problem was due to either badly-fitted floor mats, or to a defect in the accelerator pedal assembly, and has ruled ot any problem with its electronic throttle control. To me, this has always seemed a bit suspect, since the nature of the problems in some reports made me think immediately of possible software problems when I first heard of the issue. If the root cause of the problem is in software, it will probably not be easy to find.
In a sense, we have brought problems like this on ourselves. We want to have incredibly sophisticated technological goodies, which incorporate thousands of components in very complex relationships, packaged so that we can use them without having to understand how they work. We have the idea that everything can be made simple, if it is just fitted with the right sort of simple interface. As Neal Stephenson says in his extended essay, In the Beginning Was the Command Line, this idea would seem bizarre in other contexts:
… imagine that book reviews were written according to the same value system that we apply to user interfaces: “The writing in this book is marvelously simple-minded and glib; the author glosses over complicated subjects and employs facile generalizations in almost every sentence. Readers rarely have to think, and are spared all the difficulty and tedium typically involved in reading old-fashioned books.”
At this point, it seems safe to say that neither Toyota nor anyone else really knows what is behind all these reported problems. It would probably be a good thing, though, for everyone to keep in mind that there are hard problems that arise in the real world; and they cannot be made easy be declaring them so.