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A Car With A Mind Of Its Own
mindriot writes "When Hicham Dequiedt, driving on a highway between Vierzon and Riom in central France in his Renault Vel Satis this Sunday, was overtaking a truck, his car began accelerating to 120 mph on its own, apparently due to a defect in the cruise control system. Stomping on the brakes proved pointless and, having a magnetic card for a car key, he could not cut the ignition. After calling the police from his cell phone who then attempted to clear the streets of any danger to him, in what he described as the most fearful event of his life, he raced down the highway for another hour before finally managing to stop the car. Read about the incident here or, in more detail, in this article by the German 'Spiegel' (translation). The case is still under investigation. Are we putting too much trust in the increasing number of electronic systems that our lives depend upon?"
Seems simple enough to just shift into neutral and let the engine blow. Unless I'm missing something.
Something smells rotten with this story. Stomping on the brakes didn't do anything, but as he approaches a toll booth, the brakes suddenly work and he's able to stop the car??? Catastrophic system failures don't often repair themselves...
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I wonder if the electronic transmission has "safety sensors" that won't shift to a lower gear if it might cause engine damage. If so, even if you put the selector down to the first gear, the computer would override the driver in order to protect the engine.
Hmm, the computer overriding the human for self-preservation. That could be interesting.....
. 62,400 repetitions make one truth -- Brave New World, Aldous Huxley
I helped out on an accident investigation a few months ago- there were probably 400 yards worth of skid marks, the the driver of the vehicle hit the center barrier 4 or 5 times. I was trying figure out how those skids were left (she wasnt doing 600mph) when someone looked in the car and saw a sandal stuck under the gas pedal, pinning it to the floor. The back wheels were locked up because she was on the brake, but the engine kept the power to the front wheels, keeping the car in motion. Must have been a hell of a ride.
"If you can't steer and/or stop your car with the power off, you need less car."
Did you mean with brakes, or by hand? If the latter, I'm going to be really polite to you.
"Using electric brakes with metallic pads means no brake fade, ever, up to the point where you warp your rotors. There's no brake fluid to take on water and boil, not necessarily in that order."
Fade is gaseous buildup from the pads ablating against the disc, which is why you do graduated braking on a non-fancy car, but personally I wouldn't trust a solenoid to do the force multiplying work of a caliper.
As for the brake fluid taking on water...if you have a non-tight hydraulic system you'll be screwed anyway, let alone getting to the point where you have water in it. Compare the relatively low tech and _reliable_ cylinder and caliper system with the voltages/currents required to produce braking forces and you'll probably notice that there's going to some power applied.
"unreliability of automotive hydraulic systems."
Probably _the_ most reliable portion of the average motor car, if maintained and kept in good repair and not driven with utter faith in the ability to tailgate other drivers at 80mph. Most accidents involving brakes are people locking the wheels at speed.
Oddly Draconis
Too cynical to live, too stubborn to die.
My mom's '83 Oldsmobile Cutlas did this.
I had my licence maybe less than a year, and was driving home from the movies at night on the Boston Post Rd in Westchester county, NY (2 lane street, storefronts on either side.)
All of a sudden the gas pedal went down to the floor on it's own, and the car starts to accelerate from about 30, through 50 and going. Hitting the break did not disengage the cruise control, and breaking a floored car doing 50 does - absolutely nothing.
Just as I was about the turn off the key, the pedal comes back up. The whole way home the car did this. I still remember getting home, being asked what was wrong, and saying "Your fucking car tried to kill me." - this was the first time I swore (on purpose) in front of my parrents.
Next day we take it to the shop, and the mechanic's reaction was "Oh yeah, they do that." Evidently the cruise control wires, mounted on the turn signal lever, woudd fray and short out. Part of the design was the Resume button had priority over the break cut-of switch, so when Resume shorted, you were screwed.
I've met three other people who owned this car, and had the same thing happen to them. One guy, as soon as he said he'd had an 83 Cutlas, I asked "Did it ever go Flying Dutchman" on you, and he knew exactly what I met. His started revving itself next to a Cop at a traffic light. He just got out with his hands up, saying "It's not me, it's the car !", as the car sat there revving itself.
A couple of things to consider:
- The e-brake / parking brake is usually installed on the rear wheels which, due to the pesky laws of physics, only account for about 10 - 20 percent of braking power, depending on the car's configuration.
- At high speeds, it is very possible to over power the brakes. Mind you, auto manufacturers are very careful about sizing the brakes at a much larger power capacity than the engine. This is a no-brainer. However, it is possible to overwhelm the brake materials at very high speeds, causing the braking power to deteriorate. For example, if you ride the brake at 120mph, you'll lose braking capacity. If you then try to stop the car completely, the engine might have more power than what exists in the braking system under its deteriorated state. I had a caliper stick once and it heated everything up so much that I lost braking power on that particular wheel. It wasn't fun.
So the e-brake would definitely not be a choice in this matter. It should be noted that manufacturers have dropped this term and replaced it with "parking brake" for legal and marketing reasons.
Life is the leading cause of death in America.
...if this car had a manual transmission, there'd be no problem. Step on the clutch (why would you downshift instead of just holding the clutch open?), let the rev limiter protect the engine, and step on the brake. Car stops.
Because of this I'm inclined to believe it's an automatic transmission. Shifting it from drive to neutral will disengage it, and again the rev limiter covers the engine while the brakes stop the car. I'd like to see documentation of any automatic transmission that will refuse to disengage at any given engine or car speed, because that auto company would be wiped off the face of the Earth by lawsuits. I doubt such a transmission exists.
All in all, I suspect that the same thing happened here that happens in a lot of cases. I suspect he panicked when he couldn't stop the car and since nobody directly told him to shift it out of gear, he didn't think of it. Also, he managed to stop the car using just the brakes (which is as it should be; the brakes should be strong enough to stop the car under full power, assuming they're in good repair), so I further suspect that if he'd been calmer he could have stood on the brake pedal sooner.
Virg
I was in my dad's 1968 chrysler newport (HUGE car) and was driving 65 or so on cruise control. when i got into town the cruise wouldn't disengage and the 290hp motor was too much for the 4 wheel drum brakes to stop. for some reason the car would not go into neutral. i put the car through all the gears and my speed did not change. i cruised through town braking at about 50 and had a huge line of cops behind me by the time i got out of town, and when i finally got to a point of open road where i could think to switch off the ignition (i was 16, gimme a break) i was promptly thrown on the ground and handcuffed.
one of the officers didn't believe me when i said the cruise control stuck, and asked test the car himself, since it was the only way to prove to him that i wasn't purposely speeding. when he started the car again, cruise was still stuck, and the car was still stuck in gear, and VROOM 65mph. he spun around and hit a tree, steering column peirced his chest and killed him.
they kinda forgot about arresting me after that. cruise control sucks.
is bullshit. Audi owners know it well - 60 minutes did a big thing on it and it basically crushed Audi NA's brand image and sales. They renamed their entire model range twice.
The real cause ?
On the type 44 cars (Audi 4000 and 5000) the gas and brake pedal are close together to make performance driving easier.
Dumb shit americans would hit the gas pedal going for the brakes and rear end people at stops.
CBS fabricated the "expose" on the "problem" completely. Lawsuits were filed and eventually resolved with Audi showing no negligence or fault, but they still changed their pedals in later cars anyway.
My opinions are my own, and do not necessarily represent those of my employer.
This article (in French) has much more information than what we've had until now: http://www.rtl.fr/rtlinfo/article.asp?dicid=225812
Key points translated from the article:
* The driver has tried to use the brakes, but he says they quickly heated up and became ineffective.
* The driver has tried to remove the ignition "key" several times, initially without success.
* Out of ideas and quite afraid, he has called the police, and has soon been escorted by police motorcycles.
* The toll booth had been evacuated and left wide open by the police, all vehicles on the highway (around the toll booth) had been stopped and parked on the emergency lane. Even then, entering the booth at 120 mph would have been quite deadly.
* Fortunately, the driver has stopped the car 12 or 20 miles before the toll booth, by finally managing to remove the smart card that is used as an ignition key on these cars.
* Renault says there are three independant ways the cruise control system can be deactivated: using the brakes; pressing the appropriate button on the steering wheel; switching to neutral gear. The first two are electronic controls, the last one is mechanical.
* Renault says the three systems are fully independant, and it is unlikely they all should fail at the same time. Renault says the car will be brought back to its factories as soon as possible, for inspection.
* The driver was only planning to drive home, a few miles trip, but ended up more than one hundred miles from its planned destination.
In my opinion, he could have stopped the car much earlier, but was panicked. To those who say he should have had no problem removing the smart card, try doing that while controlling a car at 120 mph on a non-empty highway (at one point, he had to overtake a truck by driving on the emergency lane!).
As for the failure, there may be three independant systems, but ultimately, there's only one engine, which can go mechanically wrong.
I drive, amonst other things, a 1988 BMW M5.
:) so thats why i had no power braking as soon as the belt went.
This car has mechanical power steering and mechanical power brake assist. however, it is incorrect to say that power brakes are just a vacuum booster. Many are, but many are not, especially mid 80s german cars that didn't really draw enough vacuum for a vacuum based brake assist. (Some BMW, Audi, and VW models feature non vacuum assist)
Those vehicles have a hydraulic brake booster which is run as a separate output channel from the power steering pump. The power steering pump cant react fast enough for panic threshhold braking, so such cars have a brake pressure accumulator or "brake bomb" which stores pressurized power steering fluid. This pressurized fluid is what provides brake force assistance. Note that the power steering fluid and brake fluid are separate and do not mix; it's just that the brake power regulator uses stored pressure from the PS system to pressurize the brake system.
I recently replaced the brake pressure accumulator on my BMW.
Now, ancient brake technology dissertation aside - i have _very_ relevant experience regarding loss of steering and braking power.
I was on Brainerd International Raceway in Minnesota with my M5. This racetrack has a 1 mile long front straight, and turn 1 is banked. I was entering turn 1 at about 125mph (its a 4 door sedan, give me some slack) and midway through the turn i felt my steering get a bit "funny". I immediately recognized the loss of power steering. KNowing what i know about the car, i checked the brake pedal and found i had no power braking either.
Turn 2 can also be taken in excess of 100mph in my vehicle, but turn 3 is a 110 deegree turn that can't really be navigated above 50mph in a sedan on street tires. So I had no power steering and no power brakes, and i had to slow down 4000 lbs of vehicle, driver, and passenger from in excess of 100mph to about 40 mph.
This was no problem, honestly. You can do the entire back section of BIR without braking once you get past turn 3 if you're running a cool down lap. I really stood on the mechanical unassisted brakes to get speed down by turn 3, and then i was able to drive the car back into the pits.
The problem? The power steering pump is belt driven, and since the power steering pump also pressurizes the power brake system as described above, when the belt snapped, i lost power steering and power braking. My brake presure accumulator, which normally stores enough pressurized fuild to perform 3-4 full brake applications even in the total loss of engine power and brake assist, was faulty (thats why i replaced it a few weeks later
So, the moral of the story is
1) knowing how your car works is helpful. I got a ride over to NAPA, bought a new belt, and was back on the track for the next session. I remained calm even though i had the most difficult braking maneuver on the track coming up in less than 15 seconds.
2) The key to all driving situations is operator skillset and awareness.
Here's another short story:
Once in my 1980 BMW 528i i was cruising along the highway, with cruise control enabled. This was an aftermarket cruise control system, as it did not come on this specific vehicle from the factory. I opted to take an off ramp (which went up hill, as they often do in the midwest) and when i dipped the clutch the engine started bouncing off the rev limiter. Manually cancelling the cruise control had no effect. This took me quite by surprise so i killed the engine and slowed to a stop on manual brakes.
The cruise control cable had stuck. OPening the hood, wiggling the cable returned the throttle to the closed position.
Note that at BMW Club track events, a specific part of the technical inspection is the condition and function of the throttle return spring. Driving at speed requires nuance in the use of the throttle, a stock throttle can be a real problem.
My opinions are my own, and do not necessarily represent those of my employer.