What's with the "Kangaroo stops"?

November 26, 2006 12:18 PM

Why do American cars apparently lurch forward when the the driver gets out?

Watching American films and TV shows, it looks like any time someone stops a car, kills the engine and gets out, the car lurches forward about a foot.

What gives? Are American gearboxes (automatic boxes?) crap or can actors just not drive?

It's not something I've ever seen on the roads in England or in European films and I don't think I've ever seen a European or Japanese model do it on film either.

posted by twine42 to travel & transportation (35 comments total)

I can say that I've never noticed this, ever.
posted by mrbill at 12:21 PM on November 26, 2006

Americans are more likely driving automatic transmissions. They're probably not engaging the emergency brake, just putting it in park. So the car will lurch forward until the slack in the gears is used up, then stop suddenly.
posted by Brian James at 12:23 PM on November 26, 2006

Please give an example of a TV show or film where this happens. I suspect I'm not the only one who has absolutely no idea what you are talking about.

For starters -- wouldn't that cause the car to crash into something in front of it? How does the driver get out of the car without getting smashed by the door? How would the car magically know to move forward when the driver gets out? It just makes no sense at all.
posted by xil at 12:25 PM on November 26, 2006

I, too, am in the "what the hell are you talking about?" group.

Yes, when you put an automatic transmission vehicle in Park and then let off the brakes (which is a common approach), the car will usually shift a bit while dropping on to the parking pawl, but this is rarely more than an inch in my experience.
posted by baylink at 12:34 PM on November 26, 2006

I should have explained. I think this would happen because, first, the driver presses the brake to bring the car to a stop. While pressing the brake, he puts the car in park. He then gets out. The brake, now released, is no longer stopping the car. If there is any slope at all, the car will roll slightly until the slack in the transmission is taken up, when it will jerk to a stop suddenly. If you engage the emergency brake, this won't happen, but my experience has been most people don't use it.
posted by Brian James at 12:35 PM on November 26, 2006

What Brian James said. I see this in real life all the time so I am sure it happens in movies, and, since automatic transmissions are much less common in other countries, it is likely American movies have more of this -- which, if you aren't used to it, might well seem odd. (note that the foot can stay on the brake pedal until the driver is almost out of the door if they brake with their right foot).

I doubt the estimate of "an inch" is accurate - to me it does seem like the whole car sags forward, and it is quite noticeable.
posted by Rumple at 12:40 PM on November 26, 2006

It's not an American car thing, it's an American driver thing. Most Americans drive automatic transmission cars, and don't use the parking brake. Instead, they just put the car into Park on the transmission, and then release the foot brake, and get out of the car.

However, putting a car's transmission into Park isn't like putting on the parking brake, it doesn't halt the car exactly where it is right then: it releases a pin, which drops into the driveshaft or some other part of the transmission. However, since the pin doesn't always line up with the hole that it's supposed to go in, sometimes the car rolls a bit before the pin engages and locks the wheels. If the driver keeps their foot on the brake until they're about to get out, then the car rolls as they're stepping out.

I've heard competing theories as to whether this is bad on the parking pin (sometimes it can shear, apparently) and whether one should use the parking brake even in an automatic transmission car on level ground.

Drivers who have, or have learned on, manual transmission cars typically use the parking brake and thus the car doesn't roll.
posted by Kadin2048 at 12:42 PM on November 26, 2006

As an american, I would like to say I have never seen this either. I have seen cars rock back and forth ~an inch when quickly put into park when the vehicle was fully stopped, but I have never seen a vehicle roll AS, or AFTER the driver exits the vehicle.
posted by SirStan at 12:47 PM on November 26, 2006

As Brian James says, it's people driving automatics and not using the brake - I do this myself - although a foot in length is an exaggeration. And FWIW, I'm European and I drive a Japanese car - if that helps you with your bias in any way.
posted by forallmankind at 12:47 PM on November 26, 2006

People asking for examples - I'm sorry but I can't think of any examples which I can actually show you. Unless quoting '57 minutes into Die Hard 17' is going to help anyone.

It could be an automatic gearbox thing, but like I said, I've not seen it over here, which would add some weight to the emergency brake theory (assuming that a parking/hand/emergency brake are the same thing) since I don't know anyone who doesn't use one, regardless of the manual/auto thing.

I've never noticed it in Auto boxes that I've driven (almost all of which have been UK spec Fords).

To clarify the 'as people get out' statement, don't forget that most of those shots are when people are in a hurry, so I may be blurring the line between engine cut off/getting out/foot off pedals timings.
posted by twine42 at 12:58 PM on November 26, 2006

I've done this--that is, once in a while I keep my foot on the brake, put the car in park, and then step out of the car while my right foot is still on the brake.
posted by Jeanne at 12:59 PM on November 26, 2006

Nope, he's right. Once you notice it, you'll see it all the time. Look out for it in movies and TV.

From my experience it is exactly a result of an automatic transmission and no footbrake applied.
posted by A189Nut at 1:14 PM on November 26, 2006

People in movies are probably especially likely not to set the handbrake, because the extra motion would slow down the action unnecessarily.
posted by mbrubeck at 2:06 PM on November 26, 2006

I know my car does this, especially if I don't let up on the brake until I have turned the engine off. If I let up on the brakes and THEN turn the engine off it's less apparent.
But it's never been nearly a foot. More like three to five inches.
(I drive a '92 Buick, by the way)
posted by raygan at 2:07 PM on November 26, 2006

As a British person I've noticed this a lot in American movies (probably older ones moreso), though I always figured it was the driver stalling the car - i.e. in a manual transmission car braking to a halt (or almost halt) but not holding the clutch down at the same time. My best guess was they were just being lazy, or not used to driving a manual car. From my memories of films, it seemed like at least 3 to maybe 8 inches.
posted by MetaMonkey at 2:17 PM on November 26, 2006

It happens when people don't use the e-brake when parking auto-box cars. The weight transfer of the individual getting out is not secured through the breaking mechanism and is "eaten up" by the parking gear. This is not good for the tranny (not especially bad, but not good!).

To avoid this, when you're about to turn off your car, put it in neutral, engage your e-brake. Let go of the car break. Move the car into Park mode. No stress on the tranny. No lurch

Voila
posted by stratastar at 2:21 PM on November 26, 2006

Okay... so apparently my idea of a foot is nearer to six inches.

No-one tell Mrs Twine... she'll be heart broken.
posted by twine42 at 2:36 PM on November 26, 2006 [2 favorites]

For the record, I know exactly what you're talking about twine! :)

I think it's a mixture of the slack in the transmission (as mentioned above), and the fact American cars have such bouncy suspension compared with European/Japanese cars.

This slack-takeup is a lot more noticeable when the car is still bobbing up and down for about a minute after it stops!
posted by derbs at 3:23 PM on November 26, 2006

Brian James gave the correct answer ages ago. Second post. He couldn't be any righter.
posted by lockedroomguy at 3:45 PM on November 26, 2006

yeah, it's definitely the automatic. I remember being surprised by that when I came over here from europe the first time as well.
posted by krautland at 4:07 PM on November 26, 2006

Just agreeing that this is a common thing in american movies, but its just that they are lazy and don't use the handbrake, just put it in Park.
posted by lundman at 4:40 PM on November 26, 2006

Can someone give a reference to a movie and timestamp so I can see this? A youtube link would rule too.
posted by SirStan at 4:59 PM on November 26, 2006

Bah, nothing you see in the movies is accidental, they do it for effect. There's a whole rich history of car-related effects and devices. How many times have you noticed a scene shot through the front window where the rear-view mirror has been removed, or how many times have you heard tires squealing furiously in loose dirt? Yes the technical root of it is driver/transmission behavior but the little bounce on exit thing is purposely done to add to the sense of action.
posted by scheptech at 5:12 PM on November 26, 2006

Another angle: this can happen with a manual transmission. If you take your foot off the clutch before the engine has totally stopped, it will lurch forward. And "about a foot" is not too far off the mark. I have seen this used in movies for either comic effect, or someone in a hurry. Just throwin' it out there.
posted by The Deej at 5:13 PM on November 26, 2006

It isn't a movie thing. I've seen it in the street and done it myself many times.
posted by A189Nut at 6:17 PM on November 26, 2006

This can happen when people get out of a car in a hurry, and in movies, there are a lot of people getting out of cars in a hurry.

As you can imagine, if this really happened regularly, there would be quite a few injuries, unless the driver was always the last one out. But it doesn't. Does the Hummer on Entourage roll forward when the crew gets out? Does the SUV on The Wire that Avon Barksdale rides around in lurch when the driver gets out?

I'm an American, and I always engage the parking break before I get out of the car, no matter what kind of transmission the car has. Not doing it would be like Roger Rabbit listening to the first part of 'shave and a haircut' and leaving it alone.

And yes, giving an example of a movie in which it happens would make a huge difference.
posted by bingo at 6:18 PM on November 26, 2006

As you can imagine, if this really happened regularly, there would be quite a few injuries, unless the driver was always the last one out.

The foot-lurch is an exaggeration. The inch-lurch is more like it. You see it in TV not just the movies. The detectives pull up to a crime scene in progress, car decelerates to an almost-stop, door flys open, cops bounce out, car settles into rest position, all in one well-timed smooth motion. Actually probably something to do with suspension slack as well. If we're talking about the same thing... which maybe we're not... ok yeah, an example of the foot-lurch might help.

In any case, re. parking/emergency - it's the same thing and one good reason to use it regularly as a parking brake. Keeps things working properly for the time it's needed as an emergency brake.
posted by scheptech at 6:49 PM on November 26, 2006

Also consider that large American cars generally have a softer suspension. Besides the Brian James answer above (which is 100 percent correct), the effect the exaggerated with big cars that settle on their shocks and springs, like cheap American cop cars used for cop movies where guys are jumping out of cars in a hurry.
posted by frogan at 7:29 PM on November 26, 2006

I'm acutely aware of this whenever I parallel park, and usually compensate for the slight lurch forward (I live on a serious downhill).
posted by drezdn at 9:28 PM on November 26, 2006

Even when I park my automatic 1960's car on a hill, (and never use the e brake) my car only rolls about four inches in park. So yeah, it does happen all the time...as for the e brake thing being a lazy thing, my e brake is poor so I have to constantly tighten it when I use it on a regular basis, and I would rather have it serve it's purpose as an emergency brake should my 1960's single master cylinder drum brakes fail me.
posted by Holy foxy moxie batman! at 9:47 PM on November 26, 2006

I should mention that I don't use the parking brake as I live in fear of leaving it accidentally engaged.
posted by drezdn at 6:31 AM on November 27, 2006

Driver error. It really isn't an effect of the parking brake either. The proper way to park on an incline is to keep the foot on the brake and then put the car in park. Gently let up on the brake before getting out of the car. In shows like Cops, the officer will usually jump out of the car ASAP after shoving the gear box in park, sometimes without even coming to a complete stop. It's not good for the tranny and is pretty dangerous but sometimes time is of the essence?
posted by JJ86 at 6:46 AM on November 27, 2006

I've only seen that used for comedic effect in movies.
posted by electroboy at 7:07 AM on November 27, 2006

I've noticed it before. Seems like it occurs most often in a 70s era cop movie. Bet it happens a couple of times in every Dirty Harry movie. Might be to emphasis the "nothing matters but what I need to do to catch this guy" attitude of the 70s era movie cop.
posted by Carbolic at 1:20 PM on November 27, 2006

lol, they could be forgetting they are in gear and letting out the clutch like I did the other day!
posted by occidental at 10:12 PM on November 27, 2006