Woz says there's an acceleration problem with his Toyota Prius
news.cnet.com
news.cnet.com
OK, back on topic. There's all this talk of cars accelerating out of control. Almost any car with disc brakes is able to overpower its own engine... for a little while. The biggest problem is that a wide open throttle means there is no manifold vacuum, so the brake hydraulics will be unassisted after pumping the brake pedal a couple of times. If the car is still at speed and the throttle is wide open, it will to be a lot harder to stop.
The problem of uncontrolled acceleration is due to a failure of multiple systems in ways that car designers didn't predict. All of the following are required for a car to accelerate uncontrollably:
1. An automatic transmission. In a manual the driver will hit the clutch and brake pedals to decelerate.
2. Hydraulic brakes powered by manifold vacuum. Electronic-assisted brakes are less reliable overall, but they will work reliably if the car's throttle is wide open.
3. Keyless ignition and lack of a BIG RED KILL SWITCH in a standardized location. Industrial equipment has them. Motorcycles have them. Why don't cars have them?
Each of these things alone seems like a sound decision. Automatic transmissions let drivers focus on driving instead of shifting. Hydraulic brakes are usually reliable, and they use manifold vacuum that would otherwise be wasted. Keyless ignition is convenient. But together these systems (coupled with a panicked driver) can fail in unexpected ways. I'm not trying to excuse Toyota, just pointing out that this sort of thing could have happened to any car company.
I also don't agree with your point about point #3 being a sound decision on its own. Keyless ignition is convenient, but there's no reason not to have a kill switch besides aesthetics. And they probably could have designed an aesthetically-pleasing, small kill switch.
Moving up a level of abstraction is only great when it works the way it's supposed to, and there should always be some sort of manual override for the rare, untested cases when it doesn't.
I agree that cars should have kill switches, but I forgot to mention a disadvantage of them: killing the engine kills power steering. If a driver accidentally hits the kill switch they could have trouble avoiding obstacles or making a turn. Motorcycles don't have power steering and riders are familiar with the kill switch.
Are you sure that power steering requires the main engine, or does it use a different power source? Perhaps the kill switch could disable everything except power steering, unless it's held down? I've read that turning the car off using the key doesn't disable power steering unless it's turned all the way, so that would provide similar functionality.
Some newer models (usually hybrids) power the hydraulic pump with an electric motor, and a few cars have purely electric power steering (just an electric motor, no hydraulics). In these types, a kill switch could be set up to stop only the engine, not the electrics. The battery could power the car long enough to stop safely.
What happened to the good 'ol days of harikiri (http://en.wikipedia.org/wiki/Seppuku)? I'm not really suggesting that Toyota top brass should start sharpening their knives ;) But if anyone following this story over the last year or two can say that there isn't a coverup afoot here, I'll eat crow. The proverbial heads should be rolling at Toyota.
[edit] typos
If the Toyota guys can't find it then - yes - they should ask someone who can find it.
I can only hope for a mighty public outcry and backlash against these opaque practices. It's one thing to convert more systems from mechanics to electronics. It's another thing to wrap the entire thing in secrecy and obfuscation. Ralph Nader should be leading the charge on this.
However if he can reproduce this quite easily then there is probably a software bug. And Toyota can't afford a recall. Honestly this just has to be taken to courts, its the driving force of our economy.
It doesn't mean that he is necessarily right, but he is definitely worth paying attention to.
proverbial
Does your software take into account bad sci-fi premises?
We are limited in our ability to fix bugs of that kind. Banning alcohol would probably the wrong thing to do and probably no work. What might work is automating transportation. We can at least fix the bugs there.
That's rich. That's another way of saying ... societies with people in them have bugs.
Yeah, my wife last night had a bug ... she kept wining that I work too much. If this escalates we'll probably end-up like other people getting divorced ... which could lead me into getting drunk and into a car crash. If people only automated those cars, I wouldn't have to worry about it.
Problem is, that's not a bug I can fix ... next time I'll get some automated robot that doesn't mind me working so much ... hope she doesn't BSOD on me though.
> We are limited in our ability to fix bugs of that kind. Banning alcohol would probably the wrong thing to do and probably no work. What might work is automating transportation. We can at least fix the bugs there.
No, it would only give those people with God-syndrome some sense of control.
[ http://www.multinationalmonitor.org/hyper/issues/1987/05/wat... ]
Also, why is accelerating during the park->drive transition more dangerous than sudden acceleration at speed? Seems to me like the really high speed case would be deadlier to car occupants and those around them.
Wikipedia only contains "official" "facts". There is no evidence on either side of the story, so Wikipedia just reports whatever Audi said. Complaints were limited to a specific make and model of vehicle. Would it not be rather unlikely that people who can't tell the gas from the break drove that one make and model? It really isn't important either way - the fact is that it had a real impact on their public perception and sales.
Seems to me like the really high speed case would be deadlier to car occupants and those around them.
Cars moving > 25 MPH are generally found in environments specifically designed for this purpose. Cars in "park" are generally inches from other cars, walls, people, pets... a fraction of a second travel from danger. It doesn't take much speed to fatally pin someone between a car and something else.