Talk:Anti-lock braking system

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Observation[edit]

Thought this ancectodal evidence, I must drive, on a daily basis, a vehicle equiped with hydraulically-actuated, four-wheel drum brakes, of the dual-servo, self-adjusting type. Since re-shoeing all four wheels several thousands of miles ago, I have, in a wide variety of braking conditions, experienced no brake fade. Could it be the modern linings? My car is a piece of crap, you dont even know.

I also wish to point out that the brakes lack power assist, which the servo action seem to make up for, and, that braking control driving on ice and snow was much better than what I have experienced on ABS and non-ABS power-assist front disc/rear drum equiped vehicles.-WK-139.78.96.115 01:27, 8 March 2007 (UTC)


Safety during ABS failure[edit]

This is probably something that should be mentioned. Back when ABS was first introduced, cars still had a manual proportioning valve for braking. While this was not as important when a car was equipped with disc brakes on the front, and drum brakes on the rear.. it was absolutely ESSENTIAL when a car was equipped all around with disc brakes.

Without a proportioning valve (anywhere from 65%-75% for the front disc brakes, and the rest to the rear), such a car will receive a 50/50 split in braking power, front and back. This is _very_ bad, as you will soon find the rear of your car attempting to slide in front of you, as it is much lighter than the front. This is especially evident when trying to brake whenever the road is slippery, be it rain, snow or ice.

This is why such a proportioning value exists, and all pre-ABS (and most 80s and 90s ABS systems) still had a value in place. These days, however, ABS is more advanced. ABS can actually detect individual wheel skid, and apply pressure independantly on each wheel, something early ABS could not to. This has lead to the removal of manual proportioning, which means that each wheel in a modern ABS system recieves equal braking pressure, if ABS is offline.

This is bad, very very bad. If ABS malfunctions, not only is the driver (and likely a driver that has never learned to brake without the ABS crutch) without ABS, they now have a car that can not effectively brake in poor braking conditions. While a skilled driver can easily compensate for the rear sliding out of control, it does make the situation more difficult. Even a skilled driver would have to reduce braking power significantly, with 50% braking power at the rear. An unskilled driver, especially one braking without ABS for the first time, would find themselves in serious trouble.

This removal of the proportioning value is a relatively new thing for standard consumer automobiles. Subaru, for example, just started doing it in 2004, I believe. VW and others have been doing it for quite some time, but I believe well under a decade. While on the surface it may appear to make sense (hey, this means we can fully use the rear brakes), this is seldom the case. Front and rear brakes are tuned, matched to the car, the proportioning value meant to prevent skidding of the rear brakes before the front. Many cars had a value that would even auto-adjust dependant upon the weight over the rear axle.

This is all gone now, in an attempt to simplify construction and save costs. I deem it a serious and potentially fatal mistake. Effectively, the "backup system" that ABS had (reversion to manual proporitioning) is now gone. ABS fails, and braking turns into a very dangerous matter.

I think there should be some mention of this, in this article ....

Comments?

Nicely written. You'd have to do a comparison between the safety advantages of a full authority ABS, versus the safety advantages of an ABS that had stopped working but which operates better in that mode. Actually, I sort of agree with you anyway. My specific concern is that if we are cornering at say 0.4 g and apply 0.4 g of braking, without a proportioning valve we have not changed the balanace of the car, that is, it will tend to drift outwards (ie braking is neutral steer). With a proportioning valve we tend to overload the front tire more, so giving more understeer. In an emergency it is probably better to give more understeer to the average driver.

Greglocock 10:51, 22 June 2006 (UTC)

More thoughts on brake proportioning valve. Even if the vehicle does not have a BPV it does still have a natural brake balance, governed by the relative sizes of the pistons. Typically I see 40mm rear pistons, and 60 mm front pistons, ie almost exactly the traditional 70:30 split in braking force, as it is a square law. Alternatively they vary the number of pistons per calliper. I can see no advantage in commonising on the larger size, and obviously the front piston diameter is set by required performance and system pressures, so at a guess production cars with ABS, without BPVs, will still brake in a reasonably balanced fashion if the ABS fails. Greglocock 23:51, 16 September 2006 (UTC)

On 13 google hits for "Antilock brake controller". "Antilock brake system" gets 4,930.

+++Does it work at low speeds? Hi, I have read the car bibles article on braking, which says:

"The hidden gremlin of ABS - what they don't advertise. If you look at the statistics for crashes, a large percentage of them are "fender benders" - low-speed impacts that only do a little damage and so slow that the vehicle occupants are in no danger. Less than 15mph normally. I'll give you one guess what the typical "minimum activation speed" is for ABS. That's right. Your average ABS system is useless much below 15mph. Seriously. Try it yourself. Find an empty road on a slight downhill grade - even better if its on a dewy morning. Run your ABS-equipped car up to about 15mph and jam on the brakes as hard as you can. The car will skid to a stop and the ABS system will remain totally silent."

http://www.carbibles.com/brake_bible.html

Is this true? If so, should it be included in this article. Thanks!! --Turtle 18:38, 1 June 2006 (UTC)

Yes it is true. ABS is deactivated at low speeds because the SAFETY advantage is minimal, but the difficulty of making it work at low speed is very great. A locked wheel is the best way to stop on many surfaces at low speed.

Greglocock 01:31, 2 June 2006 (UTC)


+++Effectiveness.

I don't think you can make the absolute statement that ABS will NEVER increases braking distances on tarmac, wet or dry. The reason I say this is that with ABS the slip velocity oscillates around the optimum. With conventional brakes a truly skilled or lucky driver could hold the wheel at the optimum slip velocity.

Also, the calibration has to be a compromise between wet and dry road conditions. I don't know how much the optimum slip velocity changes with surface water, but would hazard a very informed guess that the optimum slip velocity for wet tarmac is significantly lower than for dry tarmac.

However if you have data that shows otherwise I'd be happy to agree.

Cheers

Greglocock

Background[edit]

Maybe some words on what ABS is supposed to do would be in order. What happens when brakes lock and how does ABS counter this?

Good suggestion. GL

Invention[edit]

The Dunlop "Maxaret" system was introduced on the Jensen FF way before this, in the mid-late 1960s. Just because it didn't have the name "ABS" shouldn't mean the article shouldn't talk of it -- this isn't a Bosch ad. I'm going to be researching the facts on earlier ABS systems to get this article a bit more neutral. —Morven 10:31, Jun 12, 2004 (UTC)

Good call, the Bosch Automotive Handbook has an excellent overview of the Lucas system, which I suspect is somewhat based on the Maxaret. greglocock


++++++++++++++++++++++++++++++++++

First edit by John Gwynne


> How much such systems actually reduce braking distances on bitumen is a subject of debate and depends, in any case, on driver skill. A moderately skilled driver capable of cadence braking would get little benefit from an ABS system compared to a novice driver.

However since few drivers have any significant skills, understandably the real world demands that a lowest common denominator approach is taken.
On what do you base this claim? --JonGwynne 23:18, 8 Oct 2004 (UTC)
Well let's see. What percentage of drivers know how to cadence brake? What percentage of those drivers have the presence of mind to use it in an emergency? Is the product of those two percentages likely to be greater than 50%? Common sense and experience tells me that most people lock the front wheels, and leave them locked. GL



>The recommended technique for non-expert drivers, in a typical full-braking emergency, in a straight line on a highway, is to press the brake as firmly as possible and to steer around the obstructions. However, in real-world emergencies of this sort, a novice driver will rarely (if ever) retain the presence of mind to do anything but stomp hard on the brake pedal and steer straight ahead.

But apparently they will be able to cadence brake? Ridiculous
That's not what I said. Try reading it again.--JonGwynne 23:18, 8 Oct 2004 (UTC)
True, in detail.GL


>Some automotive engineers argue that is a better practice to design a car so that it is more difficult to lock up the brakes in the first place. This is done by making the car lightweight and balancing the braking system so that the force applied by the driver during a "panic stop" would be insufficient to lock the wheels.

Cite? This implies designing a system that does not exploit the full braking potential of the tyre.
That's simply not true. In independent testing, non-ABS-equipped TVRs and Nobles significantly outbrake other, ABS-equipped vehicles. e.g. Recent testing by Autocar Magazine: TVR Tuscan S, 100-0 in 4.15 seconds, Noble M12 in 4.11 seconds. Compare to a lighter, ABS-equipped Vauxhall VX-220 that took 4.72 seconds. Slightly heavier BMW Z4 4.39.--JonGwynne 23:18, 8 Oct 2004 (UTC)
So what? If they are not on the verge of locking the wheel then they are not exploiting the full braking potential of the tyre, /for that vehicle/. I'm not saying that is a bad decision (although the same exercise on wet roads might reveal why that is not such a great tactic). GL
Speaking as someone who has made panic-stops in a non-ABS-equipped TVR Tuscan on a wet tarmac, I don't have any problem with the idea of making a light car with big tires that grip well enough to stop hard when the brake pedal gets stomped on. What's your problem with it?--JonGwynne 01:20, 11 Oct 2004 (UTC)
You are arguing from a very specialised point of view. Demonstrably normal drivers have a greater difficulty in stopping a car successfully in wet weather. GL
I make no claims to exceptional driving ability. My panic-stop (though simulated) in the TVR was just that: both feet on the pedals (brake and clutch) as hard as possible and steering wheel dead center. I was deliberately trying to lock the wheels to see how the TVR would handle it. It never, even for a split second, lost control and stopped in a perfectly straight line faster than I ever hope to stop again. If it hadn't been for the seat-belts catching me, I'm quite certain I would have broken ribs on the steering wheel. My point is that ABS isn't the magic-bullet that some people would like car-buyers to think it is. A properly-designed car can stop just fine without it. And, if a small company like TVR with a shoestring development budget can do this, there is absolutely no excuse for a big carmaker not to follow suit.--JonGwynne 22:49, 11 Oct 2004 (UTC)


>In gravel or snow, there is no question that ABS increases braking distances. On these surfaces, the action of the wheels locking causes them to dig into the material and create a buildup of ahead of the locked wheels which helps stop the vehicle more quickly. ABS prevents this from occurring. Some ABS controllers attempt to mitigate this problem by slowing the cycling time, thus letting the wheels repeatedly, briefly, to lock and then unlock again.

Cite? Can you demonstrate that an ABS that has been calibrated for gravel increases braking distances compared with the average driver on gravel?
Increased braking distances for ABS on friable surfaces is well-established, do you dispute this?--JonGwynne 23:18, 8 Oct 2004 (UTC)
No. Reread my comment. GL
So can we at least return this paragraph to the article?--JonGwynne 01:20, 11 Oct 2004 (UTC)
I'd suggest you lose the first sentence, or modify it along the lines of "In gravel or snow, there is no question that ABS increases braking distances over those that a trained driver can achieve."
Why? That isn't the truth. The truth is that while braking on friable surfaces, who is driving is not the point. The car without ABS is going to stop faster because the locked wheels will dig into the surface and built up an increasing mound of material ahead of the car to aid in stopping. ABS prevents this and increases the braking distance. You want to argue about professional drivers vs novices on tarmac, that's one thing - but this is a competely different situation.

>Another effect of ABS on slippery surfaces is that it helps the driver to maintain control of the car under braking rather than going into a skid. With 4-wheel ABS, the driver is able to brake and steer at the same time in order to avoid an obstacle, without having to worry about entering into a skid. The problem is that in certain situations, it is actually better for the car to go into a spin in order to reduce the stopping distance by coverting forward motion into rotating motion.

Cite? breaks laws of physics. Check out conservation of momentum.
Perhaps you can explain what, for example, ice-skaters are doing when they appear to be able to convert their forward motion into rotating motion (and vice versa), seeing as how you're the physics expert. --JonGwynne 23:18, 8 Oct 2004 (UTC)
If you don't understand that then you shouldn't be lecturing other people on brake systems. The reason circuit driving instructors encourage non ABS drivers to spin off when they have lost control has very little to do with stopping distances. GL
I'll take that as a "no" as in "No, you can't explain it and will now drop the subject"--JonGwynne 01:20, 11 Oct 2004 (UTC)
Incorrect and correct respectively. GL
You can't have it both ways. Either explain yourself or drop it.--JonGwynne 22:49, 11 Oct 2004 (UTC)
As a physics student, and one who wants to help out those not so familiar with physics, here is my opinion: If the wheels are turning, the car will follow a certain path, as determined by the direction of the front (sometimes back as well) wheels (see steering). This only requires a certain frictional force to be supplied by the ground. However, if the car skids, then the maximum frictional force will always be applied, which may stop the car faster. (I haven't read the articles I linked to.) Brianjd 11:35, 2004 Dec 23 (UTC
This is just wrong. When objects are sliding, it's called kinetic friction. when there not sliding, it's called static friction. Static friction is always higher. When a tire is turning on the road, it is not sliding or skidding and has the highest friction. Braking forces can be increased until just before the transition between rolling and skidding. I doubt you've ever been in a physics class in your life...this is high school physics.69.122.62.231 17:45, 13 November 2007 (UTC)
Sounds to me like someone is just a little upset that their ABS sacred-cow has been challenged. The fact remains that there are some serious issues with ABS, including the tendency of inexperienced drivers to be lulled into a false sense of security by them which encourages unsafe driving - I've seen this one firsthand. Now, do you want to stifle legitimate criticism of ABS or do you want to work on a version of the article that tells the whole story? --JonGwynne 23:18, 8 Oct 2004 (UTC)

Perhaps I should add, in certain well defined conditions there is no doubt that a skilled driver can outbrake a standard ABS equipped car. I don't know that a skilled driver could outbrake an ABS that has been set up for that particular condition, mind you. For instance in F1 Mclaren (I think) had a car that had different ABS setups for each corner (from memory) which was banned on its second race. However, for the average driver in realistically variable conditions, including poor road surfaces, moisture, variable camber and obstacle avoidance, combined with the average driver's lack of observation and skill, ABS offers him a better chance of survival than standard brakes, in most situations. Whether it also encourages him to drive harder in the first place is an interesting question. GL

I can't speak to any experimental prototypes that McLaren may have been developing, but the fact is that none of their roadcars were equipped with ABS because Gordon Murray felt that the car performed better without ABS. He has repeated stated in various interviews that if he had to design the car over again, he wouldn't have done anything differently. I can only assume that he includes the car's braking systems in this.
And arguing that a professional driver in a non-ABS car may or may not be able to outbrake a novice in an identical car with ABS set up for exactly that condition is a bit of a red-herring. Fact of the matter is that in roadcars, ABS has to be set up in a generic manner to handle a wide variety of conditions which creates a non-optimal setup for most conditions.
As to your final statement about average drivers under variable conditions, ABS offer a "better chance of survival" only in some conditions and not in others. Remember, there are many difference scenarios where locking the wheels to a lesser or greater extent would be beneficial. Another point that this discussion hasn't yet addressed is the contention that the availability of ABS can act to discourange proper development of a car in general and its brakes in particular. Why should a car company spend the development money to keep weight down and to balance braking performance to the car when they can just slap ABS on the car and say "we're done"?
My point is this: even uncontroversial safety-features like seat-belts are not universally effective - there are conditions in which someone in an accident will be killed *because* they were wearing their seat-belts and would have survived if they hadn't been. Airbags are dangerous to children and even smaller adults - particularly in convertibles during rollover accidents. Traction-control and electronic-stability control systems can (like ABS) encourage novice drivers to drive in an unsafe manner because they have too much faith in the ability of these things to compensate for their lack of ability. These are important issues and should be discussed.--JonGwynne 01:20, 11 Oct 2004 (UTC)
I agree, they should be discussed, but those discussions should not be the main part of the Wiki article. As you can see from my "Effectiveness" entry in this Talk, I am not happy with the absolute claim that ABS is always better. When I find some non-proprietary objective data then I will expand the article. GL
Of course they should. Otherwise the article is just an ABS propaganda piece. The well-established shortcomings and failings of ABS must absolutely be part of any discussion on the subject, wouldn't you say? Wouldn't it be a good idea to discuss some of the reasons why world-renowned automotive engineers like Gordon Murray and Peter Wheeler deliberately designed their high-performance cars without ABS specifically because they wanted their cars to have the best braking systems they could and they determined that ABS was an obstacle to this goal?--JonGwynne 22:50, 11 Oct 2004 (UTC)

+++++++++++++++++++++++++++++++++++++++++++++++

Compromise edit by Jon Gwynne (14 Oct)

Yes, that is better. You do understand that it is not the weight, per se, of the vehicle that reduces the need for ABS in dry conditions? The reason you can get very good braking performance with big tyres on light cars with low CGs is that there is less weight transfer, and the tyres are operating more nearly in their linear range.

I trust you agree that the weight is the most significant factor involved (though obviously not the only one) in determining the speed with which a car can brake itself to a stop on any surface, with or without ABS. Lower weight means less inertia to overcome. All other things being equal or even equivalent, the lighter car will ALWAYS brake faster.--JonGwynne 18:03, 17 Oct 2004 (UTC)
Sort of. If a car were slightly heavier but fitted with much stickier tyres than a lighter one then the heavier car would win. Leaving the tyre out of the equation is to miss most of the point.Greglocock 06:17, 19 Oct 2004 (UTC)

As I said before, I'll rewrite this when I find some published data on the direct effect of ABS on stopping distances, but I'm losing hope. A direct comparison of the same car with ABS switched on and off is not good enough, since the 'off' case won't have been set up correctly.Greglocock 09:45, 17 Oct 2004 (UTC)

Not sure what you mean about the "set up" here. I remember an article in one of the car magazines a while back that compared the braking performance of a car with switchable ABS. If memory serves, it was a Mercedes. So, in many ways probably not an ideal candidate for this test since the brakes were probably pretty easy to lock up - especially in the wet. Maybe that's what you mean by "set up". --JonGwynne 18:03, 17 Oct 2004 (UTC)
Traditional brake systems have brake proportioning valves, and use different calliper geometries (etc) front and rear, so as to give a reasonable brake balance. ABS cars do not need to do this, they can compensate for significant differences in brake performance wheel to wheel, or axle to axle, by altering the line pressure. Therefore an ABS equipped car with the ABS switched off may not have good brake balance (if it was designed to be switched off then this is, admittedly, unlikely). The Merc test would be a good one, can you find it again? Greglocock 06:17, 19 Oct 2004 (UTC)
But I trust you would agree that it would be better for a car (with or without ABS) to have the brakes set up to provide maximum stopping ability without locking the wheels, right? I trust you would also agree that installing ABS on a car allows the designer (if they choose) to not spend any effort setting the brakes up for maximum stopping abillity because the ABS will prevent any of the wheels from locking up. In other words, you seem to be saying that ABS is a band-aid fix for sloppy engineering. Is that right? Incidentally, I agree with that statement.--JonGwynne 17:56, 21 Oct 2004 (UTC)


Meanwhile here's a couple of references
http://www-nrd.nhtsa.dot.gov/vrtc/ca/capubs/sae1999-01-1286.pdf
Thanks for the link. Unfortunately, they don't make clear the methodology of the studies they cite. I did some digging on the Kahane study and it turns out that it was a simple survey of data from FARS (Fatal Accident Reporting System). There doesn't seem to be any investigation of why (or even *if*) ABS was the determining factor in the reduction of accidents. But, even granting his assumption that ABS was the sole cause for the reduction in accidents, even Kahane admits, when referring to the NHTSA's own tests, "Stopping distances decreased substantially with four-wheel ABS on wet surfaces, but decreased only slightly on dry pavement and increased considerably on gravel"--JonGwynne 17:56, 21 Oct 2004 (UTC)
http://www.ibmwr.org/prodreview/abstests.html
You did know that this was for motorcycles only which, because of their weight and wheel-configuration, have more of an issue with wheel-lock under braking.
Which demonstrate pretty conclusive evidence that ABS is beneficial in the wet, at least.Greglocock 06:33, 19 Oct 2004 (UTC)
I'm not sure I'd agree that is was conclusive, but I would say that it is very suggestive. The problem is that the other aspects of cars have also been improved since ABS was introduced in road cars. Brakes, tires (compound and tread-design), suspension, chassis-balance, etc. have *all* improved dramatically in that same period. To give sole or even primary credit to ABS for the overall improvement in performance is to make an unwarranted (though obviously appealing) assumption.--JonGwynne 17:56, 21 Oct 2004 (UTC)

ABS and NON ABS[edit]

ABS only stops a person from locking up the brakes which in turn would make the car stop quicker then if the person had locked up the brakes. A car with bigger disk pads and disks all round could stop faster then a car with ABS on a car with smaller disk pads and disks. But only if the brakes on the first car without ABS was not locked up. Skidding or sliding makes you lose control of the car and will take longer to stop. Also the road conditions and tread type on the wheel will be a great factor in the stopping distance. Richard Mendoza

The article contradicts this - under some conditions, locked wheels build up material in front of them, stopping the car faster. Brianjd 11:48, 2004 Dec 23 (UTC)

The common average driver[edit]

This discussion is all very interesting, and quite possibly more informative than the article itself. :) But I'm curious how often the average driver encounters a "friable" surface. I've only encountered gravel in parking lots and back country roads, not exactly places where I usually need to worry about high-speed skids. And the snow-covered roads here in northern Ohio are always packed down solid due to the amount of traffic, and I don't see how a locked wheel is going to dig into the snow in any capacity. Am I missing something obvious here? (And as far as spinning reducing momentum, even if that's true, how often does one have room to spin around uncontrolably on a highway or city street?)

Further, being someone who admittedly knows zilch about cars and only a scant bit of what I learned in high school physics, this article leaves me with the impression that antilock brakes aren't worth it and are ineffective on snowy and icy roads. "The primary benefit of ABS on such surfaces is to increase the ability of the driver to maintain control of the car rather than go into a skid—though loss of control remains more likely on soft surfaces like gravel or slippery surfaces like snow or ice." If this is truly the case, then every manufacturer of antilock brakes should be sued for false advertising, because as far as I'm told, the main purpose of antilock brakes is to prevent skids on snow and ice. So what, are we only supposed to use ABS on wet roads? Or is that one a lie too? I'm not trying to be snarky here, I really would like to know -- I'll be purchasing a new car this year, and had previously thought ABS would be a no-brainer for Ohio winters, but now I'm not so sure. Leaving out ABS would mean saving a few thousand dollars because I could get a lower edition of the model I want.

If you're buying a new car in the US, I doubt that ABS is going to be offered as an option (i.e. something you can safe money by leaving off). Also, even for someone like me who is highly critical of ABS, I am the first to admit that on certain types of cars, it is good to have. In fact, if we really want to get into hair-splitting here, my beef isn't with ABS per se, but with the tendency of car designers to use ABS as a substitute for better car design. Ideally, cars would be lighter and would, therefore, stop more quickly and safely with or without ABS. Without ABS, car companies would have considerable incentive to make cars lighter and more responsive. But with ABS, they simply don't have to. It is cheaper and easier to slap ABS on the car than it is to cut 1,000 lbs from the curb weight. If you're buying a car with Ohio winters in mind, I would recommend looking hard at Saturn. Their use of plastics for body panels has a double benefit - corrosion resistance and cheap/easy replacement in the event of a fender-bender. --JonGwynne 05:50, 21 Jun 2005 (UTC)
Interesting. I can't speak for all car manufacturers obviously, but the car I'm particularly interested in is the Honda Civic, because of its excellent safety ratings and good gas mileage (for an automatic... actually the difference between the manual's and automatic's gas mileage isn't that much). In the case of the Civic, ABS is only offered in the EX trim level, which is $3650 more than the Value Package, but since the EX also throws in other features I can't say for certain exactly how much ABS is adding to the cost. In reality I would probably be going for at least the LX though, so the difference is really only $1900 for me, which is still a nice chunk of change. I have a few friends who bought Saturns in the past few years and they seem to be pleased with them as well. --Birdhombre 12:22, 21 Jun 2005 (UTC)
Also, what our Aussie friend says below about taking driving lessons is an EXCELLENT idea for someone who is going to be driving in tricky winter conditions. There is absolutely no substitute for experience. If I were a passenger in a car, I'd trade all the electronic gizmos in the universe for a driver with a clear head and experience in keeping/regaining control of a car on a slippery road. So, especially if you have a family, ask the dealer if they have a winter-driving class they can sell you as part of the price of the car. You want to get out in a controlled situation where you can practice what to do if the car gets frisky on you. --JonGwynne 05:58, 21 Jun 2005 (UTC)

One last thing, then I'll shut up. Every person I've talked to about antilock brakes (also all non-experts) gives the explanation that, "it's better to tap the brakes repeatedly when you skid on snow and ice, but the ABS computer can do it a lot faster than your foot can, so it's more effective." Is that an oversimplification, or just incorrect? The article doesn't seem to explain it this way, as far as I can tell. But if this is the popular conception among the public, perhaps this notion should be debunked in the article. --Birdhombre 18:36, 15 Jun 2005 (UTC)

That's a simple explanation but not terribly inaccurate. Think of it this way: If you want to stop as quickly as possible, what's the ideal way to do it? Answer: To press down on the brake pedals just hard enough so that the tires don't break traction and start to slide rather than turning. Right? On a dry, grippy surface, this usually isn't a problem. But when things get slippery... that isn't as easy to do because it would require the ability to predict the future (i.e. "If I press harder on the pedal, will the tires lock?"). So, in the real world, there are two options. One is for the driver to manually "pump the brakes" (i.e. press the pedal repeatedly as quickly as possible) - sometimes called "cadence braking". This allows the brakes to work a portion of the time by releasing and then reapplying them repeatedly. The other option is to let an ABS computer do this for you automatically. The computer has a sensor on each wheel and when you put on the brakes it makes sure the wheels keep turning. If one of them stops turning, it assumes that the wheels has locked and releases the brakes for that wheel. Then when the wheel starts turning again, it reapplies the brakes... it then repeats this process potentially hundreds of times every second and, depending on the car, possibly does it independently for each wheel. So, not only is ABS faster than your feet and brain could be, it would also require you to have four feet and four brake pedals in order to try to match it.
The heavier a car is and the more power-assist there is in the brake system, the more benefit the driver will get from ABS. The reasons for this should seem obvious - heavier cars have more mass to stop and are more likely to skid in the first place. Also, heavy vehicles are more likely to have higher-powered hydraulic brake systems which make it more difficult to get the kind of fine control needed for effective cadence-braking. --JonGwynne 05:50, 21 Jun 2005 (UTC)

Reply to "The common average driver"[edit]

All good questions.

Friable surfaces - in Australia (where I live) only about 20% of the roads are paved. The vast majority of back country roads are colloquially known as gravel roads, consiticing of hard packed gravel. Conventional ABS does not like this stuff at all.

So far as hard packed snow goes, I don't know, we don't get much here, what I wrote is the conventional wisdom.

ABS faces the same problem on a flat sheet of ice as you, there is virtually no grip. That's just a fact of life. What it can do is to make sure that when you try and steer at least some grip is available for that, whereas if you lock the wheel then turning the steering wheel has no effect.

I'd say the main advantage with ABS is that in dry, damp, greasy, wet and some snow and ice conditions they offer increased controllability. On snow, and friable surfaces, they are probably less good than a reasonably skilled driver familiar with the conditions, who is not panicking. The last is a significant point.

I'd say for a normal driver in normal traffic conditions in non frozen conditions on sealed road ABS is an extremely positive safety system. I would specify it on my own car in preference to side air bags, which cost about the same.

Your friends don't understand about driving on loose snow. You don't tap, you brake hard, release, steer, straighten the wheel, brake hard, etc etc. It is a learned skill, I'd go on a driving course if I were you. I believe that a driver who has mastered this will probably be able to outbrake an ABS equipped car in some conditions, if he is wide awake.

Greglocock

The effect of ABS on loose ground has been tested with a Mitsubishi Pajero several years ago (in the sand dunes of some desert; the braking tests were done while driving down a sand dune). Without ABS, the car would dig into the sand and come to a rather abrupt stop. With ABS, the car would not lose any speed during the downhill section. This behavior is independent of the driver skill. Of course, both results (with and without ABS) are perfectly acceptable in such sparsely populated areas like the Sahara desert :-) --Klaws 10:02, 17 November 2005 (UTC)


Effect of vehicle weight[edit]

"It is worth noting that the heavier a vehicle is, the more it will benefit from ABS. This is particularly true of vehicles with less-sophisticated hydraulic braking systems where fine control is not as easy as with the more developed braking systems. Conversely, lighter vehicles, especially sports cars with highly-developed braking systems without ABS can outbrake comparable vehicles even with ABS."

In my opinion the overall meaning of this paragraph is bordering on hogwash. The last sentence is OK, but the first sentence is unmitigated tripe. Does anyone have any real evidence that heavy vehicles need ABS more than light ones? There may be some sort of valid idea in there, in which case it needs to be expanded. If there is any evidence for it, I guess the idea might be - "for a given set of tires a heavier vehicle is more likely to benfit than a light one.". But I still can't really justify that.

The middle sentence just seems to be flim-flam to me.


--Greglocock 22:44, 5 August 2005 (UTC)

Some types of "heavy vehicles" benefit from ABS in a somewhat different way. Yes, I'm talking about trucks and vans. When a truck is not loaded, the rear wheels will lock easier. So when a truck driver leavews a loading bay, the brakes will behave differently than maybe a few minutes ago. ABS relieves the driver from adjusting his braking power to the load. The same is, btw, true for Traction control systems. I checked it with different Merced-Benz Sprinters in both empty and fully loaded conditions (on wet tarmac). Yo, I guess any observers would have thought "Man, look at that idiot...where did he learn to drive...did he learn to drive?", but that didn't keep from conducting this important scientific experiment. ;-) --Klaws 10:02, 17 November 2005 (UTC)
That is what Electronic brakeforce distribution (EBD) is for - it appropriately apportions braking effort based on vehicle loading - efectively replacing the load sensing valves or pressure limiting valves for the rear brakes. -- Teutonic_Tamer (talk to Teutonic_Tamer) 10:07, 14 May 2008 (UTC)

Operation / effectiveness[edit]

I moved the para discussing the pulsing feel and driver responses from effectiveness to operation as it seemd to me more a development of the arguments in operation than the preceeding para in Effectiveness. I also referenced the (directly relevant) Munich & Copenhagen taxi driver experiments discussed in risk compensation.

Thanks for that. Interesting stuff

Greglocock 03:46, 11 November 2005 (UTC)

Operation - Detection needs more info?[edit]

In the article, it states:

The electronic unit constantly monitors the rotation speed of each wheel. When it senses that any number of wheels are rotating considerably slower than the others (a condition that will bring it to lock1) it moves the valves to decrease the pressure on the braking circuit, effectively reducing the braking force on that wheel and causing a characteristic pulsing feel through the brake pedal.

and I'm sure that's how some ABSs work.

However the How Stuff Works article mentions a system that senses a rapid deceleration in the wheel to activate. (btw: this system seems to me to make a lot more sense - it wouldn't be fooled by multiple wheels locking up)

Can anyone verify this?

Budbrake[edit]

unless anyone can find proof of the opposite I suggest that the Budbrake is not an ABS device. It is a brake proportioning system. ref http://www.bikeforums.net/archive/index.php/t-83704.html . I'll give it a week and then rv the advert for Budbrake.


Greglocock 03:24, 16 January 2006 (UTC)

History of ABS systems[edit]

I just wanted to point out that soem Ford vehicles starting in the early 1970's had a "SurTrak" braking system, and in fact the Lincoln Mk IV article directs to this one. There is no mention of this system at all in the article, which is curious since this would predate the Mercedes introduction by several years. Any thoughts? --Mfree 16:16, 12 July 2006 (UTC)

Awfully bosch-centric[edit]

Lots of other brake skid control systems have been used, including analog systems. A poster already mentioned the Ford/Lincoln system of the early 70s. Another was the Chrysler system used initially on the '71 Imperial. Brake pressure modulation was achieved through remote mounted vacuum servos (like power brake boosters) and cylinders under control of an electronic module. Very clever, moderately complicated, and quite effective from everything I've read. —Preceding unsigned comment added by 146.6.202.126 (talkcontribs) 21:04, 24 July 2006

Fair enough, so why not add your information to the article? The reason the article is Bosch-centric is that Bosch publish the most information on ABS, and (at a guess) supply most systems that are used. Greglocock 02:39, 25 July 2006 (UTC)

The 0-100-0 Test[edit]

This test is a very poor indicator of braking performance. For most cars the 0-100-0 test result is mostly a test of power to weight ratio, not primarily braking performance. The only cars for which it is truly a test of braking performance are those which are traction limited for the entire run, which discounts any production car. Also, what on earth is a comparable car? Same tires, same engine, same gearing, same suspension, similar weight?

Note that I agree, a good skilled driver, in a straight line, on dry roads should be able to beat ABS. Demonstrably in the wet in turns even very skilled drivers have problems where ABS would help. That's one of the reasons they 'banned' it in F1

Greglocock 02:15, 12 September 2006 (UTC)


If you consider the braking segment of the test, certainly that would be a good indication of braking performance. That's one of the reasons the test is set up as a "0-100-0" test - as opposed to quarter-mile sprints and other such things in which folks from North American like to indulge. Wouldn't you agree? --SpinyNorman 04:08, 12 September 2006 (UTC)
OK, so do you have access to these split times? If so can you put together a comparison? The only information I have seen that looks like a halfway reasonable comparison is the motorbike one, where, braking from high speed, the BMW rider could beat the BMW ABS, but the Yamaha guy could not beat the Yamaha ABS.
To be honest this article needs a rewrite, as there is too much scrappy information in there (the locked brake comparison is silly for example), I'd suggest : quick desrciption, history, longer technical description of typical current system, advantages, disadvantages, studies of impact on accident rates, would be a better format. For the latter section I have seen (but need to find again) a pdf with a breakdown of accidents across 5 states Greglocock 05:19, 12 September 2006 (UTC)
No, even the number of the breaking segment doesnt's indicate "anything": Aerodynamics start playing a role in how much force the tyre can transfer to the road above 30mph and those forces increase with square of the speed - other Factors are the Tires (wider and softer is better), the Suspension (how "constant" is the contact between Tyre and road) ..
Unless you test _exactly_ the same car once with ABS and once without, those numbers don't tell anything about the general capabilities of ABS.
And considerd that a good driver may be able to hold one Tyre at the optimal point (10-20% friction), since he just has one Pedal the 3 other Tyres most likely are not exactly at the optimal Point - ABS however can break every Tyre individually... (on a motorbike the Situation might be a little different, since the rider actually can controll every single Tyre - at least on most of the bikes) —Preceding unsigned comment added by 14:18, 16 September 2006 (talkcontribs) 80.128.179.237
I don't think you are right, threshold braking is possible, is regularly practiced, and is demonstrably better than ABS at stopping in a straight line in the dry. If you were to take a production car and switch the ABS off then these days you would probably find the rear locking up too early, since we no longer bother with a brake proportioning valve. So, you'd actually need to set the non ABS car up properly first. Incidentally the brake proportioning setting is surface dependent, so fine tuning the brake proportioning is in itself a driver aid. If I get time (unlikely) I'm going to investigate whether I can beat the ABS in an ABS car by using threshold braking, as opposed to mashing the pedal, which is the recommended technique. Incidentally can you sign your posts in future? Greglocock 22:36, 16 September 2006 (UTC)

Too automotive-centered - more about aircraft[edit]

I couldnt find a similar article for aircraft anti-skid systems - i guess this could be something somebody could add - their is hardly anything on this topic in this article 81.221.177.166 07:56, 27 September 2006 (UTC)

There's a 1954 Flight advertisement for the original Dunlop Maxaret system here: [1] —Preceding unsigned comment added by 86.112.203.140 (talk) 13:04, 14 April 2009 (UTC)
If I get a chance, I'll paraphrase some of the basic information in my repair manuals at work. Most of the anti-skid devices in aircraft are painfully manufacturer specific. 184.153.196.39 (talk) 00:22, 3 November 2010 (UTC)

I believe that the Lear Jet, first marketed in 1963 was equipped with antilock brakes. This may have been the first vehicle to universally use an ABS system, and I'll keep looking for verification...to be added later Homebuilding (talk) 13:23, 27 March 2012 (UTC)

When did anti-lock brakes become more widespread?[edit]

We need something on when anti-lock brakes became more widespread.

Also, do all vehicles nowadays come equipped with anti-lock brakes? We should include something along those lines as well. —Preceding unsigned comment added by SkinnyZan (talkcontribs) 05:08, 29 October 2006

this article needs to be looked at. it's full of confusing mistakes!69.122.62.231 02:28, 2 February 2007 (UTC)
Anti Lock Brakes do come standard on a lot of vehicles, but they are still an option on a decent number of of other vehicles as well. —Preceding unsigned comment added by 72.236.173.22 (talk) 18:26, 19 September 2007 (UTC)

This article is poorly organized and unclear[edit]

As an individual who is not car savvy and reading this article for the first time, I'd like to voice my concern that it is a bit disorganized and unclear. It starts out OK, but seems to degenerate into a jumble of conflicting information about whether or not ABS is good or bad. Could someone please reorganize it and make it more concise? Maybe a "pro" and "con" section? Right now it is very difficult to come away from the article with any clear sense of the subject matter. 68.61.241.9 01:40, 3 February 2007 (UTC)DB

ABS and braking distances.[edit]

Sigh. After skim reading through some of the comments above, I was compelled to reply myself. There is a massive debate about whether or not ABS reduces stopping distance (or more specifically, braking distance). Well I'm not a mechanic or a scientist so I'm not going to be the one to say whether or not it does, but what I CAN say, is that you are all missing the point. The anti-lock braking system was designed for one purpose: to allow the driver to steer the vehicle whilst applying maximum braking pressure. It was NOT designed to reduce braking distance, although this is possibly a side-effect of ABS.

If a child runs out in the road in front of you, your first instinct is to brake as hard as you can and steer to avoid them. Without ABS, there is a high chance your wheels will lock, thus causing the steering to have zero effect, and therefore you hit the child. With ABS, you brake as hard as you can and steer, since the anti-lock brake assist computer is ensuring the wheels do not lock at the same time as keeping a high amount of braking force on them, you are able to steer away from hitting the child.

OK: so you argue that locked wheels will stop a vehicle faster than ABS can. But who cares? I'd happily sacrifice a metre or two if it meant I was able to steer around the obstacle I was aiming to avoid, because why does it matter if it takes you longer to stop, since you've already swerved around it anyway?

For the less enlightened of you, I suggest you take a look at this video. --Janipewter 12:24, 8 August 2007 (UTC)

Yes I agree that if what you are trying to avoid is a randomly moving object, ABS is clearly the better choice. HOWEVER, if you are just trying to stop (ie you are coming up on a busy intersection and you have a red light), you don't need to steer around anything... You just need to stop! There have been plently of times that I have come up on intersections on a snow packed road, and the ABS has completely over reacted because the tires naturally don't grab as well on flat snow. As a result I've sliped into the intersection because the car thought I was doing an emergency stop and had to avoid something, when really, I just wanted to stop in time for the red light...

I'm a pretty "clear headed" driver, and I would NEVER be going fast enough on a residential road (where a child might run out) that being able to steer would be an asset. To me, if you are going 60mph on a highway and you see an accident happen right infront of you, yes, ABS is good because you obviously don't have enough time to completely stop since you are travelling at such a high rate, so being able to steer is still good! On a 20mph city street, the kid has to run out at the VERY last second for you to not be able to brake the car normally anyways (because it's a low rate of speed)... Therefore, if the kid runs out right at the last second, I doubt there is enough time for your brain to say to your head "turn the steering wheel!" much less "hit the brake!". Last summer I was involved in a crash, where a person made a left turn from the opposing direction, right in front of me at the last second... It was so sudden, that I didn't even have time to get my foot to the brake before I hit the side of their car... I was only travelling at probably 20mph, and there just wasn't enough time to react because she pulled out maybe 10 feet infront of me...

All those videos of ABS working on a snow covered track somewhere are misleading too... Only an idiot would jam on a non ABS brake, thus causing the typical skid/fishtail. The ABS cars always stop right infront of the pylons! The only problem is that they are probably going at about 40mph and then jam on the brake... I'd like to see a slow speed ABS stop on snow... It would "shudder" right over the pylons! --mmmfloorpie 14:14, 31 January 2009 (UTC)

In my book someone who repeatedly ends up sliding through an intersection for the same reason is rather a long way from being a clear headed driver. YMMV. Greglocock (talk) 22:18, 31 January 2009 (UTC)
This winter when it snows I will make a video comparing stopping distances on loose surface with, without, and while interrupting ABS function. I have a switch which can disable ABS on the fly in my vehicle (which I use while racing, mostly), and I've tested this before. I assure you that ABS causes a HUGE increase in stopping distances on loose surfaces. On tarmac the difference is negligible, and the benefits certainly outweigh the drawbacks for an average driver.

History Section Nearly Plagiarized...[edit]

http://www.absbrakes.co.uk/

The only difference is the 3rd paragraph was switched up a little...this was only the 2nd result when ABS was searched on google. It should probably be rewritten/cited, but i don't have the time to do Either, unfortunately, at this moment. —Preceding unsigned comment added by 72.236.173.22 (talkcontribs) 18:24, September 19, 2007

  • Well spotted, it looks like the majority of the article is copied from that site. 62.31.71.203 00:49, 28 September 2007 (UTC)

The (BMW) standard fitment section/line circa 1986[edit]

The article states that BMW were the 1st to fit ABS as standard. IIRC it was Ford who in 1985, a full year ealier fitted ABS as standard across the range to its Granada & Scorpio cars. —Preceding unsigned comment added by 86.128.81.243 (talkcontribs) 22:39, 18 November 2007

Yes, for the Granada and Scorpio ONLY, not over the entire vehicle line. M-B and BMW introduced ABS (as standard) on the 7-Series and S-Class (W126) sometime in the early 1980s. OSX (talkcontributions) 04:56, 9 February 2009 (UTC)

I was really surprised to see that there is no connection to Mercedes-Benz in this article since the company has been a pioneer in many areas of automobile safety. Daimler-Benz became the world's first motor manufacturer in August 1978 to officially launch the second-generation anti-lock braking system and to offer it as an option from December 1978 – initially in the S-Class. Since 1984, ABS has been standard equipment on Mercedes-Benz passenger cars. Mercedes-Benz also adopted a pioneering role where ABS for commercial vehicles was concerned. As early as 1981 ABS was offered for compressed-air brakes, a joint development with Wabco. ABS has been standard equipment on all touring coaches of the brand since 1987 and on all trucks of the brand since 1991.

I am not German but would like to have the facts right. If one reads the German version of Wikipedia then one notices that the articles are not the same though they do share some information (facts). — Preceding unsigned comment added by Runarsson (talkcontribs) 14:38, 2 December 2012 (UTC)

What do you mean by second generation? Are you sure that isn't just a marketing term? Germans are pretty gullible by and large when it comes to asserting engineering prowess by a German company. Greglocock (talk) 20:28, 2 December 2012 (UTC)

original German language[edit]

The term "Anti-lock Braking System" was originally coined by Bosch, and the correct German term by Bosch was Anti-Blockier System, hence the ABS acronym. Bosch never actually included the word "brake" in their name. -- Teutonic_Tamer (talk to Teutonic_Tamer) 10:55, 9 June 2008 (UTC)

That may be — have you some documentation to support this account of the origin of the term? — but it seems Antiblockierbremssystem is in wide, accepted, and formal use; see here, here, here, here, here, here, here, and here. If you don't see the word immediately, just do a page search on the partial word antiblockier. Unless there's some solid documentation that Antiblockiersystem is correct and Antiblockierbremssystem is not, it will be best to refer to both in the article. —Scheinwerfermann (talk) 18:08, 9 June 2008 (UTC)

Is there any evidence that the English acronym ABS derives from the German name? Because I think it is much more likely that the English abbreviated form would be derived from the English full form: Anti-lock Braking System. Indeed, this is the position taken by the folks at Merriam-Webster [2] , American Heritage Dictionary, and Random House Dictionary [3]. The claim that the English abbreviation is derived (independently) from the German full form and not from the English full form is highly dubious from a lexicographical point of view. nohat (talk) 03:47, 19 September 2009 (UTC)

If the abbreviation were from the English it would be ALB. It isn't. Greglocock (talk) 08:08, 19 September 2009 (UTC
ALB would be the abbreviation for Anti-Lock Brakes. But that's not what it stands for. ABS stands for Anti-lock Braking System, the title of the article. nohat (talk) 01:31, 20 September 2009 (UTC)
ISTR Honda used the abbreviation ALB, but it never caught on.Mr Larrington (talk) 13:56, 14 July 2010 (UTC)

The OED says " ABS n. [perhaps originally after German ABS, initialism < the initial letters of Antiblockiersystem] Motoring anti-lock (occas. anti-locking) braking (or brake) system." (ABS, n. Third edition, June 2011; Oxford English Dictionary. Online version March 2012.)

It does only say "perhaps", but still, it's the OED and this article can't very well ignore the premier authority on etymology without very good reason.--Dennis Bratland (talk) 17:35, 3 May 2012 (UTC)

Maybe, to get some clarity on this issue, are there any noteworthy prior uses of the abbreviation ABS previous to Bosch's system of the same name? The significance of Bosch as a major third-party automotive supplier using this name was that they would sell to (and develop/adapt for) each manufacturer worldwide who would like to integrate such a system into their vehicles, as opposed to earlier systems that were developed internally by one company (Chrysler, Ford, Citroen...) and thus not available for, nor meant to be integrated into, competitors' vehicles. These earlier systems all used their respective protected names (Surebrake, Sure-Track...), which could never catch on too much as they were limited to that brand of cars. The Bosch ABS system on the other hand was first integrated (1978) into the Mercedes S-Class, and in 1979 became also available on the competing BMW 7-series. It was soon used by a large number of car manufacturers worldwide who could use this technology without having to go through their own costly development process, and it was always called ABS. That must have done *something* to spread the usage of this abbreviation, right? I'd suppose the abbreviation ABS itself was probably chosen over the competing German abbreviation ABV (Automatischer Blockierverhinderer, which is in use in German transport law and would have to be translated into something like Automatic Locking Prevention, thus requiring a different abbreviation), since it could refer to both the German and an English term (helpful for international sales of the system) - albeit not very elegantly, as the most central term of the English abbreviation, "lock", is not actually abbreviated, hence all the people confusing this abbreviation with "automatic braking system" and the likes. 77.184.167.43 (talk) 11:18, 11 May 2014 (UTC)

Skid control[edit]

Is it true what I've heard? With ABS, drivers can steer out of trouble while braking, they tend to steer to avoid & go right off the road... TREKphiler hit me ♠ 04:36, 1 September 2008 (UTC)

braking distance[edit]

When panic strikes there is no steering. Give up the dream and get real. We need brakes that can stop a car faster. The ABS systems on cars today all fail in the required mission. So then they changed the mission. Pulsing the brakes doesn't work. The brakes need to be moderated instantly by reading the point where kinetic friction turns to dynamic friction on that road at that time. That is the maximum amount of braking that can be supplied through the wheels. After that, air bags in the front grille and whatever else can be used to stop the vehicle. If retro rockets need to be employed, then so be it. The insurance companies should pay for some of the research. Which they do. But the old thinking has to go. —Preceding unsigned comment added by 69.122.62.231 (talk) 01:31, 13 October 2008 (UTC)

A rather more realisic alternatoive to your retro rockets is to use intellignet cruise controls, using millimetric radar or cameras to slow the car to prevent it colliding with the one in front. That's happening now. no need to increase mu.Greg Locock (talk) 02:22, 13 October 2008 (UTC)
I think you mean 'reading the point where STATIC friction turns to dynamic'. Kinetic and dynamic friction are the same thing. Don't confuse it with viscosity. NoHenry (talk)

The video from janipewter.[edit]

Stock baloney. More nonsense for your amusement. You're driving along and listening to the radio or on your cell. Bang a kid is in the way. You need to stop yesterday. If you could drop a hook you'd do it.

What is locking?[edit]

This whole article about anti-lock brakes assumes the reader knows exactly what locking is and what causes it. I have no idea. Therefore I have no idea what it is anti-lock brakes are trying to achieve! 78.105.78.36 (talk) 07:05, 6 August 2009 (UTC)

Can ABS be defeated?[edit]

The line "On a very slippery surface such as sheet ice or gravel, it is possible to lock multiple wheels at once, and this can defeat ABS (which relies on comparing all four wheels, and detecting individual wheels skidding)." is not entirely correct. In many systems there is a speed sensor attached to the speedometer that detects any high-rate drop in the indicated speed, not compatible with the vehicle's known maximum braking performance, which the computer may interpret as a moving-vehicle-with-locked-wheels situation. Aldo L (talk) 14:23, 8 March 2010 (UTC)

Nonetheless some vehicles that are on the road exhibit this problem. For instance I have a Lexus 400 that will happily drive into a ditch rather than stop on a gravel road. Greglocock (talk) 04:57, 9 March 2010 (UTC)

There are issues with ABS on ice, snow and loose gravel that increase stopping distance. Unless the road surface is known, and the computer programmed to compensate properly, you will not overcome this. --THE FOUNDERS INTENT PRAISE 17:13, 23 April 2010 (UTC)

Suggestion: ABS and the effect on tires[edit]

One thing that I noticed wasn't discussed is the relationship between ABS and tire life. On any hard surface, if you were to make a panic stop in a non-ABS car and skid, the locked-up tires can develop flat spots (or even fail completely) where the tire was in contact with the road. Such is not the case with ABS as the tire is essentially rolling all the time, preventing tire damage.

Geforcefly (talk) 04:37, 19 April 2010 (UTC)

Article Quality[edit]

Without getting into the technical bits and trying to factually pick the article over (honestly, I went to school for that already, never again), why does the last few portions look like copy-pasted junk that someone never proofread? I'd put it together myself but it looks like a safety article that got pasted in with no formatting control, and most of it seems irrelevant for a wikipedia entry. Furthermore, "especially when the USA government requires all 2008 and later automotive sold in USA must equip CAN bus.[13]" is not entirely accurate. Vehicles between 8,500 and 14,000 US Pounds GVWR may use SAE J1939, which would include most 3/4 ton pickups and upward. Some newer half tons might fit in there too, but I'm not sure.


Maybe it'd be better to just remove all of the junky portion and start over? It's barely readable as it is, let alone wiki-ey..

Addendum #1: And we seem to have pretty much neglected power-boosting, accumulators, and air brake ABS. The first two I really can't see where to point you except OEM system manuals; as for air brake ABS, I believe Bendix published an "Air Brake Manual" that was available in PDF format for a long time. I can't seem to find it anymore, however. 24.59.103.114 (talk) 22:41, 5 July 2010 (UTC)

Go for it, that section has been tagged for 2 years, by rights it should be deleted! Greglocock (talk) 01:07, 6 July 2010 (UTC)

Done. Chris Cunningham (user:thumperward: not at work) - talk 17:57, 7 December 2010 (UTC)

Terminology: "car" versus "vehicle"[edit]

It seems the term 'car' and 'vehicle' are used interchangeably throughout this article. Although a quick check with the Merriam-Webster On Line dictionary leads me to think that this does not result in the incorrect usage of either word it does seem to me to be of poor style. Furthermore it may seem to come readers that a car is a more specific term than vehicle -- in North America a 'car' strictly speaking would be considered a relatively small passenger vehicle in comparison to a 'truck' which is often marketed as a larger vehicle aimed at transporting construction materials. —Preceding unsigned comment added by NoCoolNamesRemain (talkcontribs) 03:02, 25 July 2010 (UTC)

factual problems[edit]

In the second paragraph of this article someone has written:

"ABS offers improved vehicle control and increases stopping distances on dry and especially slippery surfaces, on loose surfaces like gravel and snow-on-pavement, it can slightly increase braking distance while still improving vehicle control.[1]"

I checked the provided citation and could not find any evidence that anti-lock braking systems can slightly increase braking distances on dry surfaces. All evidence I could find (particularly section 2.4, which refers to track testing of abs systems) suggests that abs systems either slightly decrease or have no effect on stopping distances on dry pavement compared to non-abs systems. The text I quoted is probably just a typo, but we need to double check ourselves and make sure everything we write is factually true. If there are no objections, this sentence should be changed.

Cly8419 (talk) 22:50, 24 October 2010 (UTC)

ABS-equipped cars are able to attain braking distances better[edit]

See [4] page 23, paragraph 3. ... ... for most manoeuvres stopping distances are smaller ... However ... Also, stopping distance on snow and gravel are greater in ABS vehicle. ... --mj41 (talk) 21:36, 26 February 2011 (UTC)

How ironic that an article on Anti Lock breaking is locked[edit]

Could someone edit the article to replace, "...various different..." with either, "various" or, "different". I won't be able to sleep nights while it remains as it is. —Preceding unsigned comment added by 81.187.233.172 (talk) 18:44, 27 March 2011 (UTC)

This article has a lot of quality issues re early history of anti-lock brakes[edit]

The earliest automotive application of anti-lock control of braking that I'm aware of is on Duesenberg automobiles in the late 1920s, though it was a mechanical system and obviously not electronic ABS. Someone else may have done it before Duesenberg. Bendix Corporation in the U.S. had some of the earliest patents on electronic anti-lock braking for aircraft landing gear in the 1930s and I believe their system may have been fitted to Douglas aircraft beginning around 1935. Is there someone out there who is sufficiently well-versed on this topic to clean up this article? — Preceding unsigned comment added by Arcas2000 (talkcontribs) 05:39, 21 August 2012 (UTC)