(CNN) — Early evidence points to driver error as the reason a 2005 Prius sped into a stone wall on March 9, according to federal investigators.
“Information retrieved from the vehicle’s onboard computer systems indicated there was no application of the brakes and the throttle was fully open,” according to a statement from the National Highway Traffic Safety Administration.
The statement suggests the driver may have been stepping on the accelerator, instead of the brake, as she told police.
Note to CNN: Information retrieved from an onboard computer is not reliable in cases where the computer itself is a suspect in the crime. No one is claiming that ghosts are causing the cars to go out of control. And there is no evidence yet that a mechanical failure is the culprit, despite the NHTSA looking hard for that evidence. Alcohol is also not a factor in these specific cases (or else we wouldn’t even be talking about them). That leaves two big possibilities: sober experienced people are suddenly forgetting how to drive OR something is wrong with the software or electronics that controls the cars.
If the software that reads the control inputs has the right kind of fault in it, it may occasionally lose the ability to read and react to control inputs. It is easy for a computer programmer to imagine a situation where the part of the system that records the control settings is working fine, while the part that acts on them is failing. That would be consistent with the facts of this case. Moreover, the problem may be transient, leaving no evidence that it happened.
We don’t know what happened. We may never know. But there is no reason to assume that the computer is infallible. Computers are designed by fallible people.
Joe Strazzere says
While I agree with your point about the fallibility of computers (how could I not?), I have two issues with what your write.
“That leaves two big possibilities: sober experienced people are suddenly forgetting how to drive OR something is wrong with the software or electronics that controls the cars.”
James – certainly you would agree that there are more than two possibilities?
– sober experienced people can make mistakes
– sober experienced people can (either mistakenly or intentionally) report what they did falsely
– there is something wrong mechanically that hasn’t yet been uncovered
[James’ Reply: Sure. I was speaking imprecisely. There are more possibilities than two. But none I can think of that are plausible.
Sober, experienced people can make mistakes, but that particular mistake seems implausible to me. I have stepped on the accelerator by accident, when I wanted to touch the brake, but when that happens I immediately get off it and move my foot to the brake.
This is easy enough to check. All the NHTSA has to do is looks at the statistics. Does this problem happen significantly more often with Toyotas than with other cars? If so, then something about Toyotas is probably a contributing cause. My understanding is that this is exactly why the NHTSA has opened the investigation and why Toyota has done its recalls. Toyota admits that it has a problem and claims that it knows why the problem occurred, but their explanation does not explain the facts of the cases.
Yes, people can report falsely. But that doesn’t explain why these incidents are happening in the first place, or happening to Toyota owners more than others. Unless you are saying that Toyota owners are more likely to lie.
Yes, there may be something mechanical. They should keep looking for that, but unlike software, mechanical faults are pretty difficult to hide, and typically do not vanish without a trace afterward. But yeah, it’s possible.
Look, my business is software testing, and I detect an unwarranted faith in computers. That is the spirit of this post.]
And although the title of your post indicates otherwise, we don’t really know what CNN believes. We only know what they wrote.
[James’ Reply: We don’t even know that, I suppose. But do you have an alternative plausible explanation for them to declare, based solely on the computer log, that the driver was lying about the incident?]
Joe Strazzere says
Unfortunately, we occasionally see in the news where older drivers of Toyota and non-Toyota automobiles drive them through storefronts, front porches, etc. If I ever accidentally step on the accelerator, I too quickly correct my mistake. I hope I continue to do so as I get older.
I’m not saying that’s what happened here – I certainly have no way of knowing. But I am saying that it’s not completely implausible.
[James’ Reply: You’re right, it’s not completely implausible. I’m not seeing a balanced treatment in that article, though. I’m supplying some balance.]
Software testing is my business too. I agree with you about unwarranted faith in computers. But I also constantly read about “computer glitches” being blamed on all sorts of problems – usually without proof, and usually as a dismissive, excusing argument “What more could you expect us to do? Those silly computer screw up all the time. We aren’t to blame.”.
[James’ Reply: In this case, the dismissive excusing argument is the opposite. How about let’s not have a dismissive excusing argument in either direction? CNN should have reported that the computer showed no indication of trouble, but that, of course, the computer may have caused the trouble. They could also report that the driver says she didn’t do anything wrong, but, of course, she may be lying or mistaken.
But Joe, they used their loudspeaker of the media to suggest that the driver is lying using evidence that should have been presented more skeptically.]
I don’t know what is to blame in these cases. I don’t know if we’ll ever find out for sure. Either way, I hope we do.
[James’ Reply: Yep.]
Joe Strazzere says
Recent stories seem to indicate that no software issues have been found (at least so far).
[James’ Reply: I’d love to work on that project. I’m glad they are digging into it. The thing I find most interesting is the big spike in complaints that then tapered off. This either suggests that lots of people are imagining things, or lots of people are experiencing things that they usually ignore or workaround unless there’s a lot of public attention that encourages them to come forward.]
Joe Strazzere says
James – the NHTSA has reached their conclusion after a 10-month study.
As far as the big spike in complaints, the Washington Post wrote:
“The publicity that enveloped the federal investigations – which led to the recall of more than 8.5 million cars and congressional hearings that hauled Toyota President Akio Toyoda to Capitol Hill – “was the major contributor to the timing and volume of complaints.””
[James’ Reply: I have skimmed the report. There was strangely little there are the software. I don’t see indications that much was done to examine the software. Basically, there are a few hand-waving statements about static analysis tools. Yeah, right.
It certainly is interesting, however, that we haven’t seen a continuing rash of high profile problems with acceleration. Certainly the problem is rare, whatever it is.]
Bill Wake says
From 2013, an article describing severe process and code problems reported at the (a?) trial: http://www.safetyresearch.net/blog/articles/toyota-unintended-acceleration-and-big-bowl-“spaghetti”-code