Also pilots get proper training to handle their vehicles, car drivers not so much.
The point is, most of the options you've listed there really may be computer-mediated in modern cars. (And yes, I've heard that there's a strong correlation between unintended acceleration and older drivers, and that a lot of those cases really are driver error. But I don't think you're making that case here.)
The drivetrain spins the electromechanical motor at all times, adding drag. The drag is not just from the added mass of rotation, but also a dynamic resistance caused by electrical properties of the motor being varied in different ways so that the computer can achieve either regeneration (by temporarily changing modes to allow the motor and circuitry to act as a generator, usually during a coast downhill or to a stop), or additional braking (by electrically braking the motor, using the energy stored in the batteries, to add further resistance to the drive train at the cost of heat generation and range reduction).
If a check engine light that has to do with the electromechanical subgroups of your prius comes on (indicating a fault) those systems are disabled, meaning that the car is more or less non-hybrid during those times. Braking will feel stiff, and the car sluggish, but it is by no means dangerous to drive (unless you consider the new learning curve for the cars' performance profile to be dangerous, which it is.)
Also : Your emergency brake is indeed fully mechanical, but on newer models they may be released electromechanically via a command, i'm unsure. I haven't worked on one since the second generation.
p.s. you forgot a sub group. Your steering rack is also electromechanical. One of the first of its' kind in production. Meaning, if you ever experienced a total blackout, your steering would, too, become much more resistant. This , however, isn't considered to be a safety hazard, because at speed the steering rack does little to assist the driver. the forward momentum takes care of that. The steering assistance is mostly there for parking lot situations.
(source : I was at one time a toyota technician, and my back still remembers the recall on first generation prius battery packs, they weighed 124lbs and were way awkward to remove.)
All of these functions are electronic on the Prius (and indeed on every hybrid car that I know of that's on the roads). The balance between regenerative and regular friction braking in particular requires quite a bit of computer code and calibration to get right.
Vehicle tests confirmed that one particular dead task would result in loss of throttle control, and that the driver might have to fully remove their foot from the brake during an unintended acceleration event before being able to end the unwanted acceleration.
Every one of those approaches you suggested are, in many modern cars, fully software driven. And the article even shows an example of how a bug in the software can only be resolved through the exact opposite of what a rational person would do in a crisis.
I think the only actual mechanical failsafe left is the handbrake. Please tell me that's still sacred...
source: I have tested this at ~30-40 mph and nothing about that experience leads me to believe that it would be safer if I had been going faster, and at full throttle.
So you're probably right, it's a stretch to call the handbrake something useful in emergencies when in reality it probably wouldn't perform that function.
I don't drive cars, so i have no idea if that would conflict with normal uses of the handbrake. Perhaps it could have a position beyond the normal brake-engaging position that did this? So that if someone panics and yanks on it as hard as they can, they get the result they probably want.
Yuck!
>Luckily most the features you listed are usually implemented in separate ECUs.
What concerns me would be how the systems handle unexpected inputs.
In the article it notes that the only way to end one unexpected acceleration event was to stop using the brakes. I'm not sure if the vehicle in question has separate controllers, but if it doesn't that's a real concern that unexpected input from one tickles a bug in another.
Fair enough, but as far as I know not a valid point in this specific case.
>>Braking is a software function
Yes, but a completely separated system. The odds of both software systems failing simultaneously is getting in the hash collisions domain...
>>most Americans drive automatic (software) transmissions.
Again a seperate system, and you still have a neutral position.
Are you sure? It seems sensible to me that accelerator inputs would factor heavily into the braking system, so it seems very sensible to me that an unexpected condition in one could translate over to the other - as the article noted the only way to undo one unexpected acceleration condition was to completely remove your foot from the brake pedal. Sounds like cross-over to me...
>you still have a neutral position.
... which is likely just a software input to the transmission computer.
In all likelihood the only non-electronic failsafe is the handbrake, which I still think is a direct mechanical connection in almost all cars.
Not on my Nissan Leaf. The brake lever is a switch that turns what I assume (based on the noise) is a small motor to engage the rear brakes. As far as I can tell, everything is electronically controlled. Brakes, accelerator, "ignition", "transmission" (both in quotes because the Leaf really has neither), parking brake. If there's a firmware failure, there's not a mechanically-operated fail safe to save me.
It isn't, really, in a lot of newer cars. You have a brake override system [1] that can reduce the power output of the engine by various means.
[1]: http://auto.howstuffworks.com/car-driving-safety/safety-regu...
The gearshift in the Prius is totally electronic, and it does not allow you to switch into neutral if you're traveling above a certain speed.
I don't think this is correct (at least for 1997 - 2009 models). Could you offer a citation?
Edit: this made me curious, so I did some cursory research and found this:
http://answers.yahoo.com/question/index?qid=20100204083409AA...
According to one commenter, to shift into neutral when driving you can do one of the following:
1. Press the park button
2. Shift into reverse
3. Hold the shifter in the neutral position for 3 seconds
A video posted by a different commenter shows the driver holding the shifter in the neutral position for not quite 3 seconds, but still longer than is required to shift the car into other gears (and if my memory is serving me right, longer than is required to shift into neutral when stopped).
In any case, the most obvious way to shift the car into neutral did not work for us, and it's unlikely a panicked driver would think to try any of the methods listed above.
Aircraft investigation is really good at overcoming hindsight bias and looking at human factors in a more objective way. What seems absolutely logical for you to type, having read about these incidents before, might not be as obvious to a driver who hasn't read about unwanted acceleration but is suddenly experiencing it.
Of course, if the computer is busted, I'm assuming the long button press will be sent to /dev/null.
That is what sucks about cars with power steering, they don't get any of the benefit a car built with no power steering does.
Getting that boat of a minivan around the next corner in traffic was both entertaining, dangerous, and probably the best upper-body workout I got that year.
http://answers.yahoo.com/question/index?qid=20091121085512AA...
http://www.cliosport.net/forum/showthread.php?623742-06-Clio...!
Yes, better driver training could have made some of these faults less serious. Either by fully braking properly, switching into neutral, or other techniques. That doesn't excuse the faults though.
Software that ensures safety like this really ought to be mandated to be open-source.