QUOTE (Ray Bell @ Mar 14 2010, 20:32)

I've turned an engine off in a car with power steering... I didn't crash, even though I was totally unused to power steering at the time (back in the seventies) and it surprised me...
I've frequently switched off and used the brakes before hitting them again to pull the car up to a stop.
These things won't kill you if you know you're going to have to put more muscle into them. But an engine screaming away putting full power through the drive train can do a lot of damage.
This seems to be what the average driver doesn't realise...
It's one thing to knowingly turn off your engine when you know what is going to happen. It's something completly different to have you engine suddenly turned off because the controls are easy to be affected by mistake.
QUOTE (imaginesix @ Mar 14 2010, 21:42)

This response is symptomatic of the "everything can be dangerous" approach to design that we live with today. It's the reason Toyota put a 3 second delay on the kill switch and ironically it's reason people died. It's a whole "you're not smart enough to operate this device, let us do it for you" mentality that concludes with the operator's sometimes tragic response of "WTF is this damned thng doing no AAAAHHHHHHHHH....."
Instead of button A (or switch, lever, knob, pedal..) performing function A, it suggests function A to the Big Brain who decides according to criteria outside the operator's knowledge whether or not to perform function A. This is what resulted with the throttle opening increasing for a few seconds at the same time as I commanded it to decrease on the Mazda 3 I test drove years ago. Now that I think about it, that is a textbook instance of Unintended Acceleration, though no floor mat or driver error was involved.
I firmly believe that a properly designed human interface will give the vehicle operator physical feedback to signal to him when it is overriding his command. No buzzers or lights or soothing calm voices, just raw physical feedback. In the case of my Mazda 3 incident the pedal should not have been allowed to move further than the throttle butterfly was being commanded. In the case of the Toyota Start/Stop button, it should either work instantly, or depress gradually over 3 seconds as the timer counts down, or be replaced with a more suitable input device altogether.
If highly trained pilots are crashing because of confusion with their FBW planes, what chance is there for everyday drivers on the roads if the same thinking is applied?
You can't introduce safety features which possibly can end up doing more damage than they prevent.
Also keep in mind that there is no direct link between throttle position and pedal position, and what about cars without throttles?
QUOTE (McGuire @ Mar 14 2010, 23:11)

It was never a problem until a few automakers adopted the asinine practice of placing a giant boy-racer start button in the center of the dash. If the ignition switch is placed where it belongs, within easy reach of the driver and no one else, there is little to no danger of the ignition being switched off accidentally. You may recall that cars were built this way for many decades and the incidence rate of safety problems with this layout was essentially nil -- even with a locking steering column.
We don't need a big start button in the center of the dash. It's stupid and juvenile and serves no useful purpose. If having one means the engine stop function must also be compromised, that is even more stupid and juvenile. Someone, anyone: Tell me how that makes the least bit of sense whatsoever.
A lot have happen since the conventional ignition switch. The mechanical ignition key got assisted by an electronics to prevent thefts, this 'electronic key' then replaced the mechanical key. From there the step to a starter button is quite small, and it is convienient for the driver. A lot of things have been introduced over the years in cars just because it's convienient for the drivers. After all, had these cars had manual tranmissions, the driver could just have pressed the clutch pedals instead of turning the engine off!
QUOTE (McGuire @ Mar 15 2010, 12:13)

We've been through this before. NHTSA never made any such determination. Toyota tried to make the same claim you are about the NHTSA's findings. NHTSA then demanded a retraction from Toyota and got one.
From Ray LaHood's testimony to congress:
"NHTSA has not been able to establish a vehicle-based cause for unintended acceleration events in Toyota vehicles not covered by those two recalls. The exception was a recall of model year 2004 Sienna vans in 2009 due to a defective trim problem that could, if loosened during servicing, entrap the accelerator at full throttle."
QUOTE (McGuire @ Mar 16 2010, 12:48)

I have way too much experience with automotive electrical systems to believe that. When electrical design fails and two circuits cross, the resistance between them cannot be predicted. What the Exponent technician/lawyers are describing is not, strictly speaking, a short circuit. By definition, a short circuit occurs when a malfunction removes the load from the circuit, and the usual outcome is a blown fuse or breaker due to over-current. These are crossed circuits. No over-current, no blown fuse.
True short circuits due to crossed wires with bare insulation, etc, are generally not a huge safety problem in automobiles because the load capacity of the false connection is generally very low, often lower than the rating of the fuse. The flaw burns into the clear even before the fuse can open. Or the fuse blows and the circuit simply stops working. Crossed circuits are another matter -- the circuits are carrying their normal load, simply the wrong ones. And here we have 5V signal circuits with bugger all of 15 milliamperes on the line. It may be helpful to think not in terms of a specific resistance but its reciprocal, conductivity. What happens when a multi-pin terminal connector body fills up with oil, dirt, coolant, salt, and water? Or when two wires rub together until their insulation is bare, allowing two conductors to barely touch as the vehicle vibrates? The measured resistance will not be ~0 ohms or >1000 ohms. It will vary wildly as the two wires vibrate together and when the critical resistance is met, say ~200 ohms, the malfunction will occur. So you don't need a special or extraordinary failure to duplicate this malfunction. You need only a very ordinary failure -- two wires rubbing together.
Call it whatever you want, to have two wires crossed and then two additional wires crossed with the correct resistance of 200 ohms is too unlikely. If the resistance is higher or lower than 200 ohm the fault will be detected; to have the resistance vary wildly as you put it doesn't cut it. It's exactly 200 ohms or bust. Also, if this was the reason for SUA in Toyotas, we would have seen the same issue in other cars aswell, since many cars function the same way.