Runaway car - Is this feasible?

[GlennB]

My point to all this is, when electronics are controlling so much of the vehicle, there needs to be a way for a driver to immediately override them. Especially the start/stop button. Three seconds is a long time to have to hold that button down while your car is accelerating out of control.

Can I bookmark this for the next time I'm getting beaten up by techno-freaks in a 'totally autonomous car' debate here?

 

[MRC_Hans]

My point to all this is, when electronics are controlling so much of the vehicle, there needs to be a way for a driver to immediately override them. Especially the start/stop button. Three seconds is a long time to have to hold that button down while your car is accelerating out of control.

Three seconds does seem to be a long time. OTOH, a very short reaction also has some dangers, and it MUST be a contol you are used to operate, otherwise you may not find it in time (I rarely use my horn, and when I want to, the opportunity is usually over by the time I locate the button)(On my latest car, it is back in the middle of the wheel, where it used to be ).

Perhaps a two-stage function would be a good idea: Normal push on the start-stop has a delay, a really hard push (you'll be surprised how hard even a weak person can push a button in a panic) is immidiate shut-down.

Hans

 

[McHrozni]

The only difference with older model Citroëns is that they used they hydraulics of the suspension and the power steering. <nitpick>

They used to have hydraulic breaking as well. It's quite possible they discontinued that, though.

You're right, the power assistance would fail if you cut the ignition. Still, it was a freeway, so you can coast to a stop without much steering required.
You can still brake and steer, it just requires more strength.

Doesn't power steering progressively disengage at higher speeds anyway, or is that just an option on slightly better equipped cars? It's desirable in any event.

McHrozni

 

[Careyp74]

Can I bookmark this for the next time I'm getting beaten up by techno-freaks in a 'totally autonomous car' debate here?

I can imagine your grief, even when the article in the OP explains that all of this was happening during an emergency call to the cops, people are still calling BS.

 

[screensnot]

Here is a link to the Mark Saylor Lexus crash story. It includes the audio of the 911 call. *Warning* The audio clip is disturbing (to me at least).

http://www.momlogic.com/2009/09/911_call_released_in_stuck_accelerator_crash.php

 

[LTC8K6]

In response to some spirited debate and some odd claims on another board when the Lexus event occurred, I actually went out and did some full throttle braking tests on 2 different vehicles.

The Lexus requires you to hold the stop/start button to kill the engine when the car is in motion. The Lexus also has an odd auto shifter arrangement which can make it hard to find neutral when you are in a panic and unfamiliar with the car.

Lexus ES350 shifter in neutral. I think the driver was unfamiliar with the shifter and simply couldn't find neutral. Also, Toyota's drive by wire system apparently does not recognize brake/throttle conflicts.

At any rate, I did some full throttle braking tests on 2 different vehicles:

2008 Jeep GC 4X4 Limited 5.7L Hemi with 4 wheel discs and 5800 miles on it. Full time 4wd.

It has all the gadgets including brake assist, electronic throttle, hill start assist, hill descent control, traction control, stability control, tip start, etc. It is a CAN bus vehicle.

Tip start is similar to push-button start.

I went over to a local highway to see if my Jeep would stop at full throttle and learned a few things. I warmed the brakes up with a few stops and a little bit of dragging.

Was going downhill on an on-ramp with no one anywhere near me.

Brought it up to 60 gradually and then floored it. Let it go for a bit and then braked firmly with my left foot only, holding the throttle down with my right foot.

Braking action was strong and the Jeep slowed dramatically. It got down to about 5 mph pretty quickly, engine still roaring, but otherwise undramatic.

At about that point, the electronic throttle lamp came on and the computer dropped the engine to idle.

So, barring a brake failure, I can stop my 5.7L hemi at full throttle from highway speeds with just my left foot on the brake.

Also, the Jeep's computers recognized the throttle/brake conflict pretty quickly and set the throttle at idle.

Just did the promised light application of brake and throttle with my Jeep while moving. It did indeed recognize the conflict and try to save me. Throttle light came on and power was reduced.

At a stop, the computer allowed me to brake torque.

While moving, it intervened fairly quickly.

1996 Lumina LS 3100 V6 front wheel drive 160HP Disc/Drum ~48,000 miles - poorly maintained with an occasional anti-lock light and occasional sticking drums. Original pads and shoes. Old tires that need replacing on the front. It was about 50 degrees out, so fairly cool.

First test was with stone cold brakes. Held the car at 60 and then floored it. Braked with left foot only, holding throttle down with right foot. Very obviously going to take a while to stop. Braking action weak but clearly effective and the car did stop. Much weaker braking than I expected and much weaker than my Jeep.

Second test shortly after the first to test with heated up brakes. Much stronger braking action this time, same result. Obviously going to take longer than normal but clearly effective. Stopped quite a bit quicker this time.

Third test was to see how good the brakes were now that they had two panic stops on them. This was done with the throttle at idle from 65mph. Braking action was strong and normal.

Did a 4th full throttle test after the brakes cooled a bit. Similar results. No problem stopping.

Went about my business for a while to let the car return to normal and then did 4 more tests on the way back. These tests were to see what effect pumping the pedal had.

Held the car at 60 for a bit, then floored the throttle. Pumped the brake pedal hard 4 times and on the 5th pump I held the brakes on. Pedal was hard and high but I still seemed to have power assist. Seemed to take longer but otherwise the results were similar. I still clearly had effective brakes and they still were clearly going to stop the car, and they did.

Basically same results for the next 3 tests. I did the same thing, pump 4 times and then hold on the 5th. The brakes seemed to get more effective with some heat in them, as I would expect.

I never lost the brakes and it was always obvious that I had effective, if weaker, braking.

There was never any question in my mind that the brakes would stop the car.

Again the Lumina returned to normal quickly and the brakes acted normally after the 4 tests.

There were no apparent ill effects on the car and no warning lights. The engine temp remained normal. The transmission shifting was normal at all times.

 

[LTC8K6]

The key to stopping the car is to get on the brakes hard the first time and stay on them hard while you steer the vehicle and try to find N or kill the engine.

If you attempt to control the vehicle's speed with the brakes, instead of trying to stop the vehicle, the brakes are likely to overheat and fade and quit working.

 

[Kestrel]

The point about cutting the ignition is that it would then disable power steering, breaking, stability control etc, or so I understand.

Doesn't turning the key off also lock the steering column?

 

[Damien Evans]

According to reports.

He called Ford and the Police. They advised him to turn off the ignition, and put the car into neutral. The software over rode his ability to do so. He could not put it into neutral, nor turn off the ignition. He was talking to them and doing what they said. I can't believe it was something to dodge a fine, he nearly lost his life.

Sorry, but no. There is no way the software could have stopped him from turning off his engine, even if everything else he said was true, which I very much doubt.

 

[Careyp74]

Doesn't turning the key off also lock the steering column?

Turning it enough to cut power to the engine won't, but turning it all the way will. I believe that many, if not all cars now will not allow you to turn it all the way unless the car is in Park.

 

[Damien Evans]

I can imagine your grief, even when the article in the OP explains that all of this was happening during an emergency call to the cops, people are still calling BS.

People are calling BS because his story is just not plausible. Oh, and if he was on the phone there's a law he's broken right there (unless he had a handsfree system, which very few people do)

 

[Sir Robin Goodfellow]

It would require several unusual failures to happen at once. The shifter should always be easily pushed forward to neutral, and in most vehicles you can turn the ignition off while still in drive. The steering wheel should never lock in any key position but off. The default mode for cruise control is non-functional if any electrical problems should occur. I suppose if the cruise control circuitry somehow overheated, for example, it might cause some weird fault like non-disengagement. Still, it's a stretch to think that the cruise control could lock on and the ignition switch and a mechanical shifter linkage would fail at the same time. I guess it's possible, just very unlikely.

I agree the guy probably panicked. He may have tried to turn the key off but turned it the wrong way.

 

[Damien Evans]

Turning it enough to cut power to the engine won't, but turning it all the way will. I believe that many, if not all cars now will not allow you to turn it all the way unless the car is in Park.

Not all, but, yes, many, perhaps even most.

 

[MRC_Hans]

Doesn't turning the key off also lock the steering column?

A conventional key has an intermediate position that cuts the engine but does not engage the wheel lock. SOmetimes you need to take the key out to engage it. I'm not sure about key-card systems, but I'm pretty sure any car will allow you to cut the engine without engaging the wheel lock.. A lot of things become rather tricky without it.

But yes, I heard a story about this guy who did economy driving, setting the car in neutral and cutting the engine when going down-hill (long ago, manual transmision, rear-wheel drive, you can do that), and explaining the technique to his passengers, he actually took out the key and held it up. - Came a turn in the road ....

Hans

 

[qayak]

IThe Lexus loaner car has a push-button to start/stop the engine (no key needed). When the vehicle is moving, you need to press and hold the start/stop button for three seconds in order to kill the engine.

I don't think this is right. It takes three seconds to start the car but not to turn it off. I have one in the shop today, I will try it.

Toyota did a massive recall because of the car mat problem.

 

[qayak]

People are calling BS because his story is just not plausible. Oh, and if he was on the phone there's a law he's broken right there (unless he had a handsfree system, which very few people do)

Exactly! He could dial the phone but not turn off the ignition . . . right!

 

[screensnot]

The Lexus also has an odd auto shifter arrangement which can make it hard to find neutral when you are in a panic and unfamiliar with the car.

I agree that that Lexus shifter is a bit unusual and possibly confusing. Especially because the position closest to the "N" is not neutral, it's upshift.

But with an entire minute to think about it, you'd think they'd have figured it out. Plus, the car the Saylor dropped off for repair was also a Lexus, so I'm guessing it had the same shifter.

They also knew the road was going to end at a 'T' intersection, so I'm surprised that they would try putting it in park as a last resort.

For a while I would have bet that the Lexus electronics kept the transmission in drive, even though they tried all positions on the shifter. But, with the recent release of the statement by the guy who saved himself in the same car just three days earlier, I'm not sure anymore (that guy put it in neutral to get the car stopped).

 

[screensnot]

I don't think this is right. It takes three seconds to start the car but not to turn it off. I have one in the shop today, I will try it.

Toyota did a massive recall because of the car mat problem.

From what I hear, when the car is in motion (or maybe just in gear) it takes 3 seconds to shut it off. Apparently, a 'safety' feature to keep you from accidentally shutting the car off when you don't want to.

 

[Beerina]

The key to stopping the car is to get on the brakes hard the first time and stay on them hard while you steer the vehicle and try to find N or kill the engine.

If you attempt to control the vehicle's speed with the brakes, instead of trying to stop the vehicle, the brakes are likely to overheat and fade and quit working.

The brakes win over the engine. Now stopping from high speed, I can't say as to the overheating issue. I would hope they're engineered to be able to stop a car from max speed, under full throttle, before failing, though. Airplane brakes and wheels are required to do this -- maximum landing speed, like 220 MPH + full load weight and under full throttle, they have to be able to stop the plane and not burst into flames for 5 minutes or something.

It's a fascinating test to watch, and incredibly impressive.

 

[Shrike]

They used to have hydraulic breaking as well. It's quite possible they discontinued that, though.

Sorry, that's what I meant. Same hydraulics for brakes, steering and suspension. Nowadays only on the expensive models.

Doesn't power steering progressively disengage at higher speeds anyway, or is that just an option on slightly better equipped cars? It's desirable in any event.

Well, disengage. The amount of assistance gets less, because you need less at higher speeds (you only make small adjustments).