Can you steer a runaway car with the engine turned off?

March 13, 2006 5:43 AM

Runaway cars: After reading this recent story about a BMW that got stuck in gear with the accelerator jammed down, I don't understand why he didn't just turn the ignition off. Is it true that he'd have been left unable to steer?

It's not mentioned in that article, but I heard elsewhere that he didn't turn the engine off because the car had power steering, and he'd have been unable to steer the car.

I always thought that power steering was just a bit of assistance. The steering wheel is still physically connected to the wheels, isn't it? What am I missing here?

posted by chrismear to Travel & Transportation (45 answers total)

Best answer: Power steering does assist; if the power steering gives out, then you just have to turn the wheels manually, which is a bit harder, but still not a lot.

More likely, the power steering wasn't involved at all; in many cars, if the key leaves the ignition and the steering wheel is turned, it locks. To unlock it you have to put the key back in and jiggle it. I think that is a theft-deterrence deal, and would be really inconvenient in the given situation.
posted by duende at 5:47 AM on March 13, 2006

Hit the brakes, pull the parking brake and shift it into neutral. End of story.
posted by JJ86 at 5:59 AM on March 13, 2006

Read the article.
posted by RustyBrooks at 6:08 AM on March 13, 2006

I don't drive a stick shift much, but could he have put his foot on the clutch and kept it there until the car stopped, then turned the car off?
posted by RustyBrooks at 6:10 AM on March 13, 2006

Best answer: Yes, with the clutch in, the car's going to just coast. Same as putting it in neutral. Then apply the brakes.

Turning off the ignition will lock the steering wheel. But if you turn it off for a second, until the engine dies, then turn the key back into the "on" position (without restarting the engine), your steering will work. It may just feel very heavy without power steering in action. Same is true for the brakes, you might get one easy pump, but your second pump will feel very heavy and it will take a lot of pressure to slow the car down.
posted by knave at 6:14 AM on March 13, 2006

That story really stinks, by the way. I find the whole thing extremely hard to believe -- the combination of mechanical failures is just too convenient here. All modern cars have brakes that can overpower their engines. No mention in the article of whether he tried to turn the damn car off, either. Over the course of 60 miles, you'd think that would occur to him.
posted by knave at 6:18 AM on March 13, 2006

RustyBrooks, "I took my foot off the accelerator because it's automatic - but I wasn't slowing down at all." It's not a stick shift.
posted by knave at 6:20 AM on March 13, 2006

I kind of thought it might not be, but then he said he couldn't put it in neutral because it was stuck in gear. That could still mean an automatic, I guess, since I suppose even on my auto car I can put the car into neutral while I'm driving (not that I've ever tried, but I bet you can)

(Also he didn't say it was AN automatic, but that it (taking his foot off the brake) was automatic. I still kind of think it must have been an automatic car.
posted by RustyBrooks at 6:24 AM on March 13, 2006

er, taking his foot off the accelerator.
posted by RustyBrooks at 6:25 AM on March 13, 2006

Most cars have some sort of block to prevent shifting into neutral when the RPM is high, but if you try hard enough you can probably do it. The engine will explode like a bomb though.
posted by JJ86 at 6:30 AM on March 13, 2006

Regarding the original question... in my last 2 cars at least, I could not turn the car off without putting it in park first.
posted by RustyBrooks at 6:31 AM on March 13, 2006

Try driving a car without power steering. It is an excersize in forearm strength (parking is even harder!). I've driven many cars with no power steering (from a beatup Honda Civic Cx to a Ferrari F40). It is a luxury/safety aide, along the lines of ABS.

In this case, the gentleman could have easily gotten out of the situation unless their was a physical transmission failure with the gear being unable to be accessed by the clutch. In that case, putting down the clutch might have dropped the tranny out of the car!
posted by stratastar at 6:50 AM on March 13, 2006

That doesn't make any sense at all. If it's an automatic, it doesn't have a clutch. Even if it was a manual, with a clutch, your statement doesn't make any sense at all. Finally, even if any of it made sense, I'd rather blow up my transmission than nearly die in a fiery wreck.

Cars without power steering are easy to steer as long as the car is rolling faster than 10mph or so. In fact, power steering systems typically cut out at higher speeds for this reason. It's only when the car is nearly stopped that it's hard to steer.
posted by knave at 7:07 AM on March 13, 2006

It would be nice if the story had better explained which model and year BMW it was. The more recent, computer-laden, drive-by-wire systems always struck me as a bad glitch waiting to happen.
posted by Thorzdad at 7:12 AM on March 13, 2006

Most cars have some sort of block to prevent shifting into neutral when the RPM is high

I have never heard of this; is it a new feature? My 2002 car can be shifted to neutral at highway speeds, as can several other late-model cars I know of.

Some years back, Audis had a problem just like this. Several instances of cars racing off with their drivers furiously pressing the brake were documented. One story I read had a lady break her key off in the ignition trying to stop the engine. A highway cop had to get in front of her and smoke his brakes to stop the car. Audi never admitted any problem other than "driver error", but it almost destroyed their market in the U.S.
posted by Kirth Gerson at 7:34 AM on March 13, 2006

I thought this story sounded bogus the moment I read it. There was a similar story a couple of years back which turned out to be a hoax.
posted by unSane at 7:40 AM on March 13, 2006

Re Knave: I didn't read the article and didn't see that the car was auto. Yes steering a car on a highway with no powersteering is not hard as long as you're used to it, but at slow speeds (as I said with parking) it can be a handful if you're not used to it.

Blowing up the transmission isn't an issue of mechanical failure; you could drop it out of the car and injure anyone behind you (for example, throwing a car into reverse while coasting at 70mph can easily drop the tranny down to the ground, possibly crashing your car and anyone behind you) but i guess if you're in a situation of life-threatening peril, you need to take your chances?
posted by stratastar at 7:43 AM on March 13, 2006

Some of the comments in this thread seem misinformed, as if the commenters have never experienced the conditions described in this story. I have experienced both (a) a stuck accelerator and (b) brake failure, and let me tell you that both suck ass.

My stuck accelerator came about fifteen years ago as I was driving to work on the freeway at midday. Without any warning, and for no apparent reason, my accelerator kicked in and my car was out of my control. I'd only been driving for four years at the time, and had no idea what to do. I tried to brake, and that slowed my speed so that I could pull to the shoulder, but the car was still traveling at 30-40 mph, the engiine at full throttle. Shifting into neutral (on a manual transmission) did halt forward progress, but the engine was revving so hard I was afraid it would blow. I didn't get to test anything further because all of a sudden the accelerator went back to normal. I turned off the car and just sat on the side of the freeway for several minutes, my heart pounding. I was scared to drive. (The car never had this happen again.)

About five years ago, I had my brakes — which were in perfectly fine repair — give out after coming down a steep hill. My passenger and I glided through a stop sign at 40mph, thankful that there was no other traffic. The car rolled to a stop, and we got out. The brakes smelled terrible.f

I can easily believe somebody who was experiencing a stuck accelerator also experiencing brake trouble, and this story does not sound far-fetched to me. A stuck accelerator sucks.
posted by jdroth at 7:46 AM on March 13, 2006

The issue isn't that he couldn't shift into neutral at high speed, it's that he couldn't shift into neutral while the car was accelerating. Usually when shifting you take your foot off the gas, he couldn't do that here.

Also, it does say that his brakes worked somewhat for awhile, until they wore out.

I'm not convinced either way.
posted by joegester at 7:52 AM on March 13, 2006

Re Joedg: you can shift into neutral with your foot on the gas (it would be similar to a speed shift).

Jdroth's comment seems very pertinent to the discussion. His strategy pretty much sumarizes what you should do in the situation.

In a manual, you definitely would want to get into neutral to stop the progress, but as he said, the engine will get decimated by continuously redlining it!

I've never turned off a car while it was not at idle revs, but desperate times call for desparate mesaures
posted by stratastar at 7:56 AM on March 13, 2006

knave writes "Turning off the ignition will lock the steering wheel."

Only if you remove the key.

knave writes "All modern cars have brakes that can overpower their engines."

Not true on many, many cars, you need a lot of brake to arrest 350hp.

RustyBrooks writes "in my last 2 cars at least, I could not turn the car off without putting it in park first."

What model of car was this? I know most (all) cars made in the last 10-15 years won't let you start if you aren't in park/neutral (auto) or the clutch is depressed (manual) but I'm not aware and have never driven any car that wouldn't let you turn it off in gear.
posted by Mitheral at 8:03 AM on March 13, 2006

Best answer: Most cars I have driven have atleast a 3 point ignition system, Off, Auxilary, On (auxillary unlocking the steering wheel and allowing electronics to operate). I've turned my car on and off numerous times while driving, as well as shifted out of drive to neutral and back again. I've even shifted from drive straight into reverse by accident at low speeds. (I drive a newer Honda Accord) I get very suspicious when someone says they can't stop their car.
posted by blue_beetle at 8:09 AM on March 13, 2006

His brakes didn't fail, they were allegedly insufficient to get the car to stop. He said the brakes were holding him at 70mph for a while, leaving a trail of smoke behind him. Probably burned the pads right off, or maybe melted the rotors.

Mitheral, every car I've driven locks the steering wheel with the key in the off position. I haven't owned a BMW though. The only way to unlock it in most Japanese cars is having the key in the on position. I have plenty of experience doing that.

And I agree with Mitheral, I've never seen a car that can't be turned off in gear.
posted by knave at 8:23 AM on March 13, 2006

In a manual, you definitely would want to get into neutral to stop the progress, but as he said, the engine will get decimated by continuously redlining it!

Again, this is better than dying. Also, the engine has a rev-limiter for a reason. It could probably bounce off the rev-limiter for hours without hurting it too badly.
posted by knave at 8:25 AM on March 13, 2006

Power steering is for low speeds. On a good BMW I doubt there is much if any assist at speeds in excess of 100 mph. He should have turned off the engine.
posted by caddis at 8:26 AM on March 13, 2006

the article said it was a 318, which is a small 4-cylinder engined car (unless it had been modified) - maybe 150BHP. on my car I can certainly turn it off in gear (sometimes I forget :-) - for purposes of this discussion, it's a probably-newer 528i) but I've never tried turning it off at speed. I can turn the wheel until I shut it all the way off (which I can't do with it in gear, I can only kill the engine) and remove the key, at which point it locks. figure he probably freaked out and didn't try it.
posted by mrg at 8:26 AM on March 13, 2006

All modern cars have brakes that can overpower their engines.

That would mean that no one in a modern car, anywhere, ever, has had the experience of driving a short distance with the parking brake on before they notice and take the brake off. If you were correct, the brake would overpower the engine and you'd be simply unable to move.
posted by ROU_Xenophobe at 8:27 AM on March 13, 2006

Whatever his issue, this story illustrates yet one more advantage of manual transmissions.
posted by caddis at 8:32 AM on March 13, 2006

ROU_Xenophobe, the parking brake affects the rear wheels only. The rear brakes are responsible for about 10% of your total braking power. The front brakes are where it's at.
posted by knave at 8:35 AM on March 13, 2006

ROU_Xenophobe, the parking brake affects the rear wheels only.

Or the front wheels on some cars. Or a puny set of pads on the driveshaft on some other cars. And the reason rear brakes contribute less stopping power has more to do with weight transfer than with design.

Let's not make too many generalizations, OK?
posted by Kirth Gerson at 8:59 AM on March 13, 2006

Best answer: Another version, where he says he was afraid to turn off the ignition over concern that the PS would make the machine unsteerable. And another version with comment from BMW to the effect they don't see why he wouldn't have been able to shift into neutral. BMW is going to inspect the car, but it burned in the crash so the evidence may be gone.
Other versions, take your pick.
posted by beagle at 9:19 AM on March 13, 2006

stratastar: Ok, having done this I know that an automatic transmission will NOT drop out of the car, fly loose or do any such silly shit when thrown into REVERSE at over 60 MPH, much less neutral. It will simply kill the tranny as the friction disks inside and the planetary gears chew themselves to pieces. I also did an autopsy on the 4t60e this happened to. Sever INTERNAL damage only. If somehow (and this is damn near impossible) it really locked up, the worst you would face is a broken driveaxle (for FWD) and at best, serious one sided braking from the locked drive wheel. Let's not forget that this assembly is being driven by a FLUID COUPLING in the form of a torque convertor. For this to happen the torque convertor locking solenoid would have to be engaged and this little electronic part would have to EXCEED THE TENSILE STRENGTH OF THE ENTIRE DRIVETRAIN FROM ITSELF TO THE DRIVEWHEEL. Your modern automatic transmission has no chance of flopping out of your car, whatever speed you're driving. That is, unless you loosen all the mounts.
posted by IronLizard at 9:42 AM on March 13, 2006

Whatever, there are too many pissy/picky people in this thread. What I've said is true in 99% of cases. I didn't say that weight transfer is the reason, but that doesn't make what I said wrong. Jesus. I'm bowing out here.
posted by knave at 9:42 AM on March 13, 2006

knave writes "Mitheral, every car I've driven locks the steering wheel with the key in the off position. I haven't owned a BMW though. The only way to unlock it in most Japanese cars is having the key in the on position. I have plenty of experience doing that."

It doesn't unlock until you get to ON but does it lock when you go to OFF or when the key is removed? You've got me thinking now I'm going to start testing. I know my 66 doesn't lock (no steering wheel interlock at all). My 4X4 doesn't lock unless the ingnition is in the off position and the key is removed. My Fiero needed the key to be removed and had a steering column typical of 80s GM products. Same column on my Buick. However I can't say for sure what the behaviour on my Caravans are.
posted by Mitheral at 9:45 AM on March 13, 2006

There was also a made for television movie about something similar aptly named "Runaway Car". Anyone else remeber this (terrible) movie? It involved an unlikely series of events that caused an old car to do something like this with several passengers inside.
posted by IronLizard at 9:55 AM on March 13, 2006

IronLizard writes "Ok, having done this I know that an automatic transmission will NOT drop out of the car, fly loose or do any such silly shit when thrown into REVERSE at over 60 MPH, much less neutral. It will simply kill the tranny as the friction disks inside and the planetary gears chew themselves to pieces. I also did an autopsy on the 4t60e this happened to. Sever INTERNAL damage only."

In stratastar's defense the differential housing on a Dodge FWD A-413[1] for example, will not stand up to the differential cross pin exiting the carrier. Losing the cross pin retainer will cause grevious internal and external damage to the transaxle resulting in much of the final drive components and housing being deposited on the pavement. The retainer could fail under the forces exerted by a drive to reverse shift. Not quite loosing the whole transmission but the results are similiar. Simliar failure modes are available to many modern transmissions.

More spectcular is what happens when you loose a front ujoint if the drive shaft isn't restrained by loops.

[1] (and all finals from the same family, manual and automatic)
posted by Mitheral at 10:21 AM on March 13, 2006

I didn't say that weight transfer is the reason, but that doesn't make what I said wrong.

You implied that parking brakes did not have sufficient holding power to stop a car from moving, and supported that by saying they were rear brakes (often, but not universally true), and that rear brakes contribute a small portion of stopping power, which is true but largely irrelevant, since the question was not stopping a moving car, but holding a stopped car. Weight transfer does not affect the holding of a stopped car. So yes, it does make what you said wrong.

If challenging inaccuracies and sloppy wording makes me pissy/picky, so be it.
posted by Kirth Gerson at 10:35 AM on March 13, 2006

Regarding the Audi myth, it was proven by several car magazines, using random drivers, hidden cameras, and lots of testing, that every case where someone said the car started accelerating on it's own, the driver had actually put their foot on the accelerator instead of the brake, in panic, and just kept pressing harder, instead of getting onto the right peddle. The final conclusion was that the reason this kept happening in the audi's was the peddles were too close together.

The classic example of how brakes are stronger than engine is power braking to smoke the tires before a drag race....
posted by nomisxid at 10:43 AM on March 13, 2006

Response by poster: This has cleared things up a bit for me. In the cars I've known (admittedly not many), the steering wheel only locks when you actually remove the key. I didn't realise some cars lock the wheel as soon as it's in the 'off' position. That would explain his reluctance to switch it off.
posted by chrismear at 10:45 AM on March 13, 2006

Response by poster: It would be nice if the story had better explained which model and year BMW it was.

They said it's an 'R' reg, which means about '97/'98 over here.
posted by chrismear at 10:47 AM on March 13, 2006

More spectcular is what happens when you loose a front ujoint if the drive shaft isn't restrained by loops.

The vehicular pole vault. Always a favorite.

Also: Remind me never to buy a dodge.

The classic example of how brakes are stronger than engine is power braking to smoke the tires before a drag race....

This wouldn't include the mass of the car traveling at speed. It's done from a standstill and quite different from stopping a vehicle at high speed with the engine pulling forward simultaneously.
posted by IronLizard at 10:59 AM on March 13, 2006

Best answer: I have owned 2 BMW 3-series automatics, and I find this story to be extremely fishy. I don't believe it any more than BMW does (if you read the diplomatically worded comment at the end of the article.) You can certainly turn the engine off without locking the wheel (the BMW ignition has 5 positions; the relevant one is 'off') and you can certainly shift into neutral while the car is moving and even accelerating, although I've never tried it under very heavy acceleration
posted by ikkyu2 at 2:49 PM on March 13, 2006

odinsdream writes "The vehicular pole vault. Always a favorite.

"Which mythbusters showed to be physically impossible."


Mythbusters proved: A 1967 plymouth fury didn't flip when it's loose driveshaft hit a pothole at fifteen miles per hour.


posted by IronLizard at 3:10 PM on March 13, 2006

It's easy to recognise that hindsight is always 20:20.

That said, I struggle to accept the story as it stands.

However, no-one has really mentioned the actual driver, as opposed to the car - I appreciate the initial question was more of a technical leaning, but it's drifted a bit since the start of the thread - the guy in the car actually totalled it at a ton+ when he ran out of road. (I think all reports match on that)

So, either he *did* have a problem that he was unable to find a solution to, or he was suicidal.

Assuming the former, see my comment about 20:20 above; and if the latter, the Police have made unequivically clear that they will *not* be bringing charges to bear - ergo they have no reason to either disbelieve the mechanical aspect, nor question the mental health of the driver.

Given the Police escort that ensued, and the fact that all Traffic cars in the UK are video equipped, I suspect we will get to *see* what happened eventually, which might change peoples perspectives somewhat.

There was a case recently of a Renault I believe having the same problem - the one with a key card rather than an ignition key - which, of course, cannot be removed or postion altered whilst the engine is running. Subsequent findings following the manufacturers post-evaluation have been little mentioned to the point of being suspicious; again though, charges were not brought.

Me? I'd'a stuck it in neutral and let the engine blow, or flicked the ignition to stage 1; anything to reduce the final impact speed... fingers crossed none of us ever have to manage such a situation.

"Let's be careful out there."
posted by DrtyBlvd at 8:35 PM on March 13, 2006

It is possible that the engine would win over the brakes, if you did not try to stop but rather tried to slow down the car gradually. The brakes would then overheat and become useless. However, when applied correctly, the brakes will stop any car even under full power. Turning the ignition off would also have worked and whlie the power steering would have turned off, that would nto have affected the cars maneuverability all that much. The main problem in this situation is panic. It's very easy to panic when your car suddenly starts accelerating. So, as usual, this accident was a combination of technical and human error. As the story tells it, he did call the police from the moving car which is probably why they don't think he is lying.
posted by insomnus at 5:55 AM on March 14, 2006