The ABS discussion thread

[stringbh]

Originally Posted by DerAlte

.. fine differences, but essentially they are the same.

But, which one would you bet on in a given (say, emergency) situation? OT, I actually wanted to ask a similar question regarding Airbags as well.

Originally Posted by DerAlte

They are usually mortified of getting even a scratch, and are over-cautious.

err, oops ! then you will be disappointed big time, by my upcoming ownership thread

I did thorough research about ABS (thanks to tbhp) and came to the conclusion that I will not put money on a car without ABS. It eventually increased by budget, but, so be it.

Originally Posted by DerAlte

No, no, almost every one in family and friends advise one to get a beat up 2nd hand car first - so that if you bang something the cost is less.

(only pun intended) only for cars ?! how come we don't sponsor the same concept to much more important things in life, like girl friends !

[FlatOut]

The driver psychology involved with increasing a car's safety in interesting. People tend to reduce their safety limits when driving cars which they know are laden with airbags, abs systems, stability control etc. That is to say, they drive up to a limit of safety, so with a car with many safety features they may feel they can travel faster in poor conditions. An additional problem is that people with expensive cars laden with safety-tech may wish to demonstrate their superiority of their machine by driving faster, overtaking more etc. We are all susceptible to this, and must be aware of it.

Education should be a primary method of improving road safety. A car with poorly-maintained brakes, worn or cheap tyres, worn or cheap suspension componentry will still be unsafe no matter how many electronic aids you add to it, although of course, marginally less unsafe.

As I mentioned earlier, a car with a spike protruding from the steering wheel would be driven with the ultimate care and attention.

[DerAlte]

Originally Posted by stringbh

But, which one would you bet on in a given (say, emergency) situation? OT, I actually wanted to ask a similar question regarding Airbags as well. ...

Both - this is a critical function, and neither company will compromise on that. Ditto for Airbags.

Incidentally, neither company *makes* these systems. Usually an automotive systems company does that, like Bosch, Denso, Delphi, etc. The car company defines the interfaces and functional specifications, which in reality are based on the Vendors' previous generation systems anyhow.

This is not a difference between shirt brands where there could be a difference in the cloth used, which affects reliability and functionality of the shirt.

[Jeroen]

Originally Posted by FlatOut

I know of a couple of people who have disconnected their steering wheel airbags - they're both highly skilled and experienced drivers.

Well, they might be highly skilled and experienced but they lack common sense and if anything, understanding of the statistics involved.

But it's a free country, so if they think their skills and experiences offer, statistically, a better protection, by all means go ahead and disconnect those airbags.

Jeroen

[FlatOut]

In the late 80s and early 90s, ABS systems were improving quickly, and more expensive cars often had later systems which were an improvement on previous incarnations. Now that the technology is mature, I imagine all the systems work extremely well, although some may be more suited to certain situations than others.

I would suggest that the difference in ability between two different ABS setups is far less than the difference when comparing two otherwise identical cars but with different quality tyres and shock absorbers fitted.

Originally Posted by Jeroen

Well, they might be highly skilled and experienced but they lack common sense and if anything, understanding of the statistics involved.

But it's a free country, so if they think their skills and experiences offer, statistically, a better protection, by all means go ahead and disconnect those airbags.

Jeroen

Sure, I wasn't defending their stance, but adding detail. Their take is that they do not want to be involved in a high speed loss of control where the steering wheel explodes in their face and prevents them from using the car's controls to prevent a worse impact from occurring.

Mod Note: Please use the EDIT or MULTI-QUOTE buttons instead of typing one post after another on the SAME THREAD!

To know how to multi-quote, click here.

[Jeroen]

Originally Posted by FlatOut

Sure, I wasn't defending their stance, but adding detail. Their take is that they do not want to be involved in a high speed loss of control where the steering wheel explodes in their face and prevents them from using the car's controls to prevent a worse impact from occurring.

No problem, you should have to defend them, I don't even know them.
But somebody should tell them that statistically speaking:

- The chances of that happening are less then remote
- The chances of an airbag saving the day at less high speeds are considerable higher.

Also, statistically speaking, unless they train for these high speed loss of control events, they are not very likely to take the correct action or to react fast enough. You drive 60.000 miles per year, but if you never train on these sort of accidents you are very unlikely to react properly.

For instance, aviation has shown, again and again, its not experience that saves the day per say. It's safety conscientious and relentless training that does. Not just raking up the miles!


Lets get back on topic: ABS, did they disable that too? Because as I stated in my earlier post a skilled and experienced driver can outperform the ABS easily!! That's


Jeroen

[Thad E Ginathom]

I think there are circumstances in which ABS does not work well. In general, I find it very hard to believe that any human can do what ABS claims (at least) to do, which is to keep the brakes working at maximum efficiency by keeping them just short of lock-up. I suspect that most skilled drivers just skid to a halt. I suspect that most skilled drivers can, somehow, do that better than I can, but not better than ABS can.

Above all, most drivers are not skilled at levels above modest to average. Including me.

Originally Posted by FlatOut

As I mentioned earlier, a car with a spike protruding from the steering wheel would be driven with the ultimate care and attention.

Not here. Here, the driver would sit with a child on their lap between them and the spike.

There is almost no awareness of kinetic energy is not understood, hence the reluctance to use seat belts, and the willingness to carry a child, in one arm, on the back of a motorbike.

[Jeroen]

Originally Posted by Thad E Ginathom

I think there are circumstances in which ABS does not work well. In general, I find it very hard to believe that any human can do what ABS claims (at least) to do, which is to keep the brakes working at maximum efficiency by keeping them just short of lock-up. I suspect that most skilled drivers just skid to a halt. I suspect that most skilled drivers can, somehow, do that better than I can, but not better than ABS can.

See my earlier post. Learning to outbrake ABS is not that difficult at all and everybody can do it. Problem is, as I stated, it's easy to learn on a track, but most of us won't apply this in a real life emergency stop. You need to train very hard, very often for that to make it a reflex. So in practice you are correct. But it's great fun to outperform the box of electronic trickery!

That's why ABS is so great. Every bodies reflex is just to stomp on the brake pedal as hard as you can. No further thinking or nuance required. There are some situation where ABS does not work well, although it could probably be argued that regular braking would not work well either.

[Ketan]

Originally Posted by Jeroen

See my earlier post. Learning to outbrake ABS is not that difficult at all and everybody can do it. Problem is, as I stated, it's easy to learn on a track, but most of us won't apply this in a real life emergency stop. You need to train very hard, very often for that to make it a reflex. So in practice you are correct. But it's great fun to outperform the box of electronic trickery!

That's why ABS is so great. Every bodies reflex is just to stomp on the brake pedal as hard as you can. No further thinking or nuance required. There are some situation where ABS does not work well, although it could probably be argued that regular braking would not work well either.

I'm yet to see your earlier post. However, once I got into long argument with my friend over this same point. ABS applies and release braking force multiple times in a milisecond. Humans cannot simulate this, its simple.

ABS increases the braking distance and sometimes by good margin if its a loose gravel but the point is to provide the driver with enough drivabilty/steerability so that he/she can still maneuver the vehicle without getting locked. With the ABS equipped car, your reaction has to be faster/prompt than a non-ABS car since braking distance is increased, so thats the trade off.

Some of the situations like slush/ice/loose surface, its not useful and technology is evloving to ensure that its not activated when during such siuations / offroading situations etc. It triggers based on the difference of speed on your wheels every seconds/few seconds (like an assert in software language or trying to detect a state that cant be handled) and modern ABS systems try and avoid situations when its not required to be engaged.

Coming to a human simulating this technology, I dont believe until I see a research based analysis. So far, I havent seen one and that means its not possible. I may be wrong, but really need enough to convince myself.
Now when you have a job getting done by technology, why cant we just use it, improve it and take that job off your already under pressure nervous system! If you have a technology say car, you would use it right! you wouldnt try to simulate by running @40kph to go from point-A to Point-B!

EDIT: I read your earlier post on the prev page. I agree with pump braking one can customize the ABS effect to ones benefit. However, doesnt it involve opportunities for human errors and hard to compare with tehnology/system (that can fail too, but much more reliable than humans IMO). So, its good to know internals and learn whatever you can do to get yourself out of that panic situation, for 99.999% of drivers and 99% of panic situations it helps.

[DerAlte]

Originally Posted by Ketan

... ABS applies and release braking force multiple times in a milisecond. Humans cannot simulate this, its simple.

Originally Posted by Thad E Ginathom

I think there are circumstances in which ABS does not work well. In general, I find it very hard to believe that any human can do what ABS claims (at least) to do, ...

There could be such circumstances, but 30 years worth of testing could also mean the ones not discovered have a statistically very low probability of occurring.

And you are right - no human can match the ABS system in pulsing the brakes on/off at around 20 cycles per second.

Originally Posted by Ketan

... ABS increases the braking distance and sometimes by good margin if its a loose gravel ... Some of the situations like slush/ice/loose surface, its not useful and technology is evloving to ensure that its not activated when during such siuations / offroading situations etc. ...

1. Don't lump normal surface braking with off-roading braking - they are not comparable in the context of ABS

2. "slush/ice/loose surface, its not useful" - Incorrect, ABS actually reduces braking distance on such surfaces as compared to locked-wheels braking. Not sure what you mean by "loose surface", but gravel (with hard under-surface, like gravel on dry packed earth or road) is the only one where the braking distance could be larger (not always true, depends on what is below the gravel)

3. "its not activated when during such siuations" - where did you get this from??? It is incorrect to automatically / conditionally 'disable' systems like ABS - for ANY reason other than off-roading, which it is not designed to cater to. What would be the difference between off-roading and bad city roads w.r.t. ABS? Nothing, if you know the physics and maths of ABS.

Originally Posted by Ketan

... So, its good to know internals and learn whatever you can do to get yourself out of that panic situation, for 99.999% of drivers and 99% of panic situations it helps.

In panic situations, no matter HOW MUCH you know of the internals it will not help you out of danger. What actually works is good driving habits (prevention) and safety training (conditioning) - it conditions one's mind to have the correct reaction to a situation. Like, on a sideways skid, take foot off gas pedal, turn-to-lock in the direction of skid, back to normal and accelerate - in about 2 seconds WITHOUT pressing clutch or brake pedals. And not trying things like pulse-the-brake-pedal-as-fast-as-one-can!

[tsk1979]

Originally Posted by DerAlte

2. "slush/ice/loose surface, its not useful" - Incorrect, ABS actually reduces braking distance on such surfaces as compared to locked-wheels braking. Not sure what you mean by "loose surface", but gravel (with hard under-surface, like gravel on dry packed earth or road) is the only one where the braking distance could be larger (not always true, depends on what is below the gravel)!

On road ABS rocks, but off road I have found it to be a pain.
1. Driving on ice - The car does not stop at all. Due to nature of ABS system, wheels do not lock, and if you are on incline you will keep on sliding.
2. On dirt tracks, when wheels lock up dirt/gravel builds up providing additional stopping.
These two cases where ABS is not very good are well documented, but since ABS is very useful in 99% of the cases, overall having ABS increases your ability to avoid crashing!

[DerAlte]

Originally Posted by tsk1979

... Driving on ice ... if you are on incline you will keep on sliding. ...

Wrong tyres - not the fault of ABS. Down an incline, the brakes and treads have an enormous disadvantage of gravity acting against them.

Originally Posted by tsk1979

... 2. On dirt tracks, when wheels lock up dirt/gravel builds up providing additional stopping. ...

True - IF the underlying surface is soft. Not on road - the gravel acts like millions of marbles on a hard floor.

[Thad E Ginathom]

The car with ABS does stop on ice: I've tried it. True that I only did this at around walking pace, but then it probably would not have been safe to drive on such a surface at any greater speed!

There's a wonderful thread about learning to drive in a Scandinavian country, and passing the test there. I wonder what they teach about ABS? They are the experts: in UK we are barely taught at all how to cope with frozen/snow conditions.

[Ketan]

Originally Posted by DerAlte

1. Don't lump normal surface braking with off-roading braking - they are not comparable in the context of ABS

Dear friend,
I'm talking about the off-road situations caused by vehicles running off the road in accident situations and I'm not talking about situations where JeepThrills guys spend their weekends. I have not learnt this based on my experience but from whatever I read thru such threads and internet so some of the points may not be 100% correct but in this case the high level points that I'm trying to make is correct is my guess. Points like,

- Humans cant simulate ABS
- ABS increases braking distance to provide you steerability/control

Originally Posted by DerAlte

2. "slush/ice/loose surface, its not useful" - Incorrect, ABS actually reduces braking distance on such surfaces as compared to locked-wheels braking. Not sure what you mean by "loose surface", but gravel (with hard under-surface, like gravel on dry packed earth or road) is the only one where the braking distance could be larger (not always true, depends on what is below the gravel)

- "Incorrect, ABS actually reduces braking distance on such surfaces as compared to locked-wheels" <<< seems to be incorrect. With ABS the deceleration is slightly greater on such surface and hence increased braking distance. We are not talking about wet roads here, ABS is useful on wet roads for sure.
- Again, this is based on what I read, we have Tanveer also commenting based on his experience that confirms what I have read is correct.
- This is what I read from wikipedia and other research papers and its easy to digest without learning physics/maths - Not from my personal experience again, just based on what convinced me so far, if someone can prove otherwise, I'd love to learn the new technology you are talking about.

"In gravel, sand and deep snow, ABS tends to increase braking distances. On these surfaces, locked wheels dig in and stop the vehicle more quicklyIn gravel, sand and deep snow, ABS tends to increase braking distances. On these surfaces, locked wheels dig in and stop the vehicle more quickly"
source: http://en.wikipedia.org/wiki/Anti-lock_braking_system

Originally Posted by DerAlte

3. "its not activated when during such siuations" - where did you get this from??? It is incorrect to automatically / conditionally 'disable' systems like ABS - for ANY reason other than off-roading, which it is not designed to cater to. What would be the difference between off-roading and bad city roads w.r.t. ABS? Nothing, if you know the physics and maths of ABS.

Ok, here my point is about the evolution of technology. As we discussed earlier about the slush/icy surface where its not so effective and few more situations, technology is evolving to take care of such situation to make braking more effective. Cars provided with 'off-road' or turn off ABS switch is for the same reason and we are planning to go next level by automating the function of this "off-road" switch or eliminating it altogether.
- The evolution I'm talking about is 'brake assist', 'traction control system', 'emergency brake assist', 'brake distribution system' and finally ESP. I consider all of them as an extension to ABS. Lets not go by the name ABS but consider it to be 'enhanced braking systems'
- Now we use more sensors compared to conventional ABS systems, the system doesnt just measure the deceleration ratios on your wheel but also measures the direction taken by the car is not indicate the one taken by driver's steering weheel which is ESP (an advanced version of braking system to me if you dont stick to the different names (ABS etc) provided by manufacturers).
- Not sure which off-road situation you are comparing with the bad road situation here (JeepThrills or run-off-road situation during crashes). Either ways they are different categories and surfaces for me from speed, braking and vehicle control perspective, this may lead to some more discussions (and yes, some physics and maths too).

Originally Posted by DerAlte

In panic situations, no matter HOW MUCH you know of the internals it will not help you out of danger. What actually works is good driving habits (prevention) and safety training (conditioning) - it conditions one's mind to have the correct reaction to a situation. Like, on a sideways skid, take foot off gas pedal, turn-to-lock in the direction of skid, back to normal and accelerate - in about 2 seconds WITHOUT pressing clutch or brake pedals. And not trying things like pulse-the-brake-pedal-as-fast-as-one-can!

- I agree with you on this, my point was in similar direction. What i meant was ,, internals == how to pump brakes == good driving habits!! Good to have them on top of the knowledge of tech systems. So far, technology is not replacing good driving habits, so we need them for sure.
Like I said, its not based on my personal experience (as Tanveer could immediately comment based on his) but based on something I read from wiki and reference articles, I also read that vehicles with ABS and such advanced assist technologies are driven rashly, that point alone reduced the % of effectiveness of such systems which should purely be about the drivign habits you are talking about!

[FlatOut]

Some hard facts:

A car will stop a little more quickly with all four wheel locked up on dry tarmac than with ABS deployed. But any steering ability is lost.

A car will stop a little more quickly on uncompacted snow and in certain other condtions, including some types of ice, as mentioned above, without ABS. Indeed, using ABS down a hill on new snow may cause a run-away situation, whereas locking the front wheels will stop the car.

Audi used to provide an ABS cut-out switch for just such winter conditions. I don't think they do anymore for the reason that it may subject them to litigation, since most people do not understand these subtleties of driving.

ABS is becomiong universal since for most of the time, it provides a massive increase in motoring safety. Just remember that good tyres and shock-absorbers/suspension damping is equally important.

As Jeroen mentions, it is possible to train yourself to bring the (front) roadwheels to the point of lock-up and hold them there. However that depends on a homogenous friction surface. It also means that only the front wheels will be providing maximum retardation - with ABS in play and your foot hard on the brake pedal, all four wheels will be on the point of lockup. The only cars I ever managed to successfully use his technique with were old Alfa Romeos, Saabs and most successfully in hydraulic Citroens - the DS, CX and GS (not the later Peugeot-based Xantia, XM and BX).

I suspect that what these cars had in common was a lack of compliant rubber spoiling the front suspenion, so that there was little or no fore-aft movement of the wheel as tyre began to slow. The Citroens also had the most sublime braking with the pedal being a pressure modulator, allowing more or less high-pressure fluid to the calipers - rather than shoving a bit of brake fluid down the pipes, as in every other motor car. Its superiority (as with its famed suspension) was beyond belief - it's just that most people never drove their motor car hard or fast enough to fully realise the benefits of the technology.

Electric sunroofs, electric windows, extra chrome and other salesroom clinchers are what sell to the masses, unfortunately. Safety features took a long time to arrive in Europe for the main manufacturers, those who had designed for safety such as Saab and Citroen were perceived as just weird. Some people just don't understand something which is different and refuse to be educated.