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Sorry, while I agree with your programming statement, please be aware that with antilock brakes in most situations the stopping distance is decreased, not increased as you claim (see, e.g., http://www.abs-education.org/faqs/faqindex.htm). The reason is that usually you have better traction when your wheels are rolling, not when they're blocked. It is only in very rare situations that you'd be better off without ABS. So you want ABS even for good drivers since as a human you just aren't fast enough to modify the braking force on the wheels to keep them from blocking.

"ABS is not meant to stop you faster."

ABS *is* meant to stop you faster as well as allowing to steer the vehicle as you stop. Static friction coefficient is much higher than dynamic which means that rolling wheels get much more braking power than sliding ones. Why do you exactly think you can't steer a car while wheels are locked?

While theoretically an expert driver can brake on slightly shorter distances than a modern ABS by pushing brakes just above the locking point I still have to see that happenning in anywhere near real out-circuit conditions.

False.

In what circumstances might conventional brakes have an advantage over ABS? There are some conditions where stopping distance may be shorter without ABS. For example, in cases where the road is covered with loose gravel or freshly fallen snow, the locked wheels of a non-ABS car build up a wedge of gravel or snow, which can contribute to a shortening of the braking distance.
http://www.abs-education.org/faqs/faqindex.htm

In what circumstances might conventional brakes have an advantage over ABS? There are some conditions where stopping distance may be shorter without ABS. For example, in cases where the road is covered with loose gravel or freshly fallen snow, the locked wheels of a non-ABS car build up a wedge of gravel or snow, which can contribute to a shortening of the braking distance.

From http://www.mucda.mb.ca/aboutabs.htm

Is the stopping distance shorter with ABS?

No! From early commercials, it may have looked like you could stop on a dime. That instantaneous stop is not realistic. When braking on dry or wet roads your stopping distance will be about the same as with conventional brakes.

You should allow for a longer stopping distance with ABS than for conventional brakes when driving on gravel, slush, and snow. This is because the rotating tire will stay on top of this low traction road surface covering, and effectively "float" on this boundary layer.

A non ABS braked vehicle can lock its tires and create a snow plow effect in front of the tires which helps slow the vehicle. These locked tires can often find more traction below this boundary layer.

ABS is designed to give more steering control while breaking, not to stop more quickly (although it may sometimes do that as well). I also saw a show where they tested professional and "normal" drives with/without ABS in different road conditions. Normal people stopped more quickly with ABS in almost all circumstances. Professional drives were able to stop more quickly with conventional breaks in almost all circumstances, but especially in adverse road conditions.

Saying ABS is simply better/quicker than conventional breaks (or vice versa) is simply untrue.

Here are some quotes from the first 4 google results for "ABS stopping distances" relating to cars:

In exchange for an increased stopping distance, the vehicle will remain stable and maintain full steering since the wheels won't be locked.

On very soft surfaces, such as loose gravel or unpacked snow, an ABS system may actually lengthen stopping distances.

During 1988-91, NHTSA performed two extensive series of stopping tests involving vehicles with four-wheel ABS, on various road surfaces. The tests confirmed that ABS was highly effective in preventing yawing and allowing the driver to steer the car during panic braking. Stopping distances decreased substantially with four-wheel ABS on wet surfaces, but decreased only slightly on dry pavement and increased considerably on gravel.

Under most conditions, a vehicle with a good anti-lock brake system can stop in a slightly shorter distance than an average driver could accomplish [but] that is not the main purpose of ABS, and the difference is generally not great enough to notice or be of any real use... ABS can actually lengthen stopping distances on some surfaces, such as loose snow, dirt, or gravel, because of effects that occur during locked-wheel skidding that are unique to those surfaces.

http://www.abs-education.org/faqs/faqindex.htm

In what circumstances might conventional brakes have an advantage over ABS?

There are some conditions where stopping distance may be shorter without ABS. For example, in cases where the road is covered with loose gravel or freshly fallen snow, the locked wheels of a non-ABS car build up a wedge of gravel or snow, which can contribute to a shortening of the braking distance.

The main monetary advantage is even wear on your tires, but I'd rather blow a few hundred dollars to replace bald tires than thousands in increased insurance costs for not stopping soon enough.

And for those of you questioning my sources, it comes to you from a AAA test driver / mechanic I discussed this with back when I worked in a local garage. Even pro-abs sites (such as ABS-Education, which is funded by abs manufacturers) emphasize the turning ability over the stopping distance.

The EMP will fry the anti-lock brakes. ABS systems are designed to lock the wheels in case of system failure. (Ironic in a way...)

Bullshit. It would be totally stupid to design the system that way. If it fails while you were going down the road at 70MPH you'd have a very good chance of dying. I can't even imagine what would make you think it works this way.


From http://www.abs-education.org/faqs/faqindex.htm:

What if the ABS fails? Anti-lock brake systems are designed to be fail-safe. Nevertheless, they are equipped with a diagnostic feature that automatically activates and tests the major components each time the car is started and monitors them throughout the journey.

In the rare event of a failure, the ABS would be deactivated by its own safety circuit. A warning light goes on indicating to the driver that the vehicle is now in conventional base-brake mode.

I call bullshit, and demand references.

Do you understand how ABS works? It alternatively locks and unlocks the wheel, which gives a pulse pattern, which means you stop for a second, roll for a second, etc. (Not actually 'a second', but short, pre-determined time intervals)

Read the first 10 pages of google results for "abs increases stopping distance".

What, like;

• This one?

  "1) It isn't entirely clear that antilock braking will reduce stopping distance for the skilled driver;"

  "The IIHS report, issued December 10, 1996, notes that in single-vehicle accidents, cars with antilock brakes are as much as 44% more likely to produce fatalities than are cars without the antilock system."

• Or this one?

  "Other factors affecting ABS performance include the condition of the tires, shocks, and suspension components, as well as their design. For example, if a tire hits a bump and the shocks/springs are weak, the tire may lift off the ground and lock under brake pressure. ABS interprets lockup and releases the brakes. The more the tire is off the ground, the more the brakes will release, thus extending the stopping distance."

• Or this one?

  "Stopping distance is nearly the same for pumped brakes as it is when the brakes are locked. However, with locked brakes the driver has little, if any, control over vehicle direction. ABS pumps the brakes automatically during emergency stop. It prevents wheel lock and allows the driver to maintain a higher degree of control."

  "Most people who have tested ABS in panic situations feel positively towards them. ABS, as stated before, does not shorten stopping distance. If the driver doesn't leave enough room to stop, an accident could occur. Drivers must apply good judgement whether or not their vehicle has ABS."

• Or this one?

  "Do cars with ABS stop more quickly than cars without it? Not always. Although the stopping distance with ABS is shorter under most road conditions, drivers should always keep a safe distance behind the vehicle in front of them and maintain a speed consistent with the road conditions. While a vehicle with ABS maintains its steering capability in a sudden stop, it may not turn as quickly on a slippery road as it would on dry pavement."

• Or this one?

  "ABS technology is designed to maintain rolling traction and steering. The rolling action may produce longer stopping distances on some surfaces, such as freshly fallen snow or loose gravel."

I think you get the point. The comonality between all of thesee pages looks like this;

1. Ideal conditions are required (both road and vehicle)
2. Drivers must be trained/knowledgeable in use of the system
3. Stopping distance is not always reduced, but the steering advantage is hilighted.

The problem with light cars (a very large number of consumer purchased vehicles lately) is that they don't have the weight to keep the skipping wheels on the ground, thus dramatically reducing the efectiveness in both stopping distance and steering control, hence the reason for removing them from the likes of the Cavalier and Sunfire.

Especially in snow, gravel, and sand (loose pack) ABS will drastically increase your stopping distance (by about 200% in some cases, depending on speed and density of the material you're driving in). The plow effect by your car's tires slows the trajectory of your vehicle.

ABS isn't designed to reduce stopping distance, it is designed to give steering control. These are two VERY different things. Incidentally, locking your tires and knowing how to change directions can/will significantly reduce your stopping distance with the same amount of control, as anyone who's ever taken or instructed a crash course will tell you.

I've conducted 80KM/h tests myself, in snow (loose and hard packed), gravel, sand, and wet and dry asphalt and under many of the conditions, especially the non-ideal driving conditions, my stopping distance was increased. I will grant you that my tires did suffer more on the locking tests, but if I'm making an emergency stop, I'd much sooner replace some tires than find myself face-first in the side of an SUV/Minivan/truck/etc.

BTW, speaking of ideal conditions; This study hilights another problem with ABS - Driver reaction time and leg strength. Many (most?) women and smaller men have great difficulty in putting 100lbs pressure on their brake pedals in a real hurry, which the NHTSA has discovered increases stopping distance (150-200lbs is the desired pressure, which was difficult to attain, except by the TRC (professional) test driver).

I call bullshit, and demand references.

Do you understand how ABS works? It alternatively locks and unlocks the wheel, which gives a pulse pattern, which means you stop for a second, roll for a second, etc. (Not actually 'a second', but short, pre-determined time intervals)

Read the first 10 pages of google results for "abs increases stopping distance".

What, like;

• This one?

  "1) It isn't entirely clear that antilock braking will reduce stopping distance for the skilled driver;"

  "The IIHS report, issued December 10, 1996, notes that in single-vehicle accidents, cars with antilock brakes are as much as 44% more likely to produce fatalities than are cars without the antilock system."

• Or this one?

  "Other factors affecting ABS performance include the condition of the tires, shocks, and suspension components, as well as their design. For example, if a tire hits a bump and the shocks/springs are weak, the tire may lift off the ground and lock under brake pressure. ABS interprets lockup and releases the brakes. The more the tire is off the ground, the more the brakes will release, thus extending the stopping distance."

• Or this one?

  "Stopping distance is nearly the same for pumped brakes as it is when the brakes are locked. However, with locked brakes the driver has little, if any, control over vehicle direction. ABS pumps the brakes automatically during emergency stop. It prevents wheel lock and allows the driver to maintain a higher degree of control."

  "Most people who have tested ABS in panic situations feel positively towards them. ABS, as stated before, does not shorten stopping distance. If the driver doesn't leave enough room to stop, an accident could occur. Drivers must apply good judgement whether or not their vehicle has ABS."

• Or this one?

  "Do cars with ABS stop more quickly than cars without it? Not always. Although the stopping distance with ABS is shorter under most road conditions, drivers should always keep a safe distance behind the vehicle in front of them and maintain a speed consistent with the road conditions. While a vehicle with ABS maintains its steering capability in a sudden stop, it may not turn as quickly on a slippery road as it would on dry pavement."

• Or this one?

  "ABS technology is designed to maintain rolling traction and steering. The rolling action may produce longer stopping distances on some surfaces, such as freshly fallen snow or loose gravel."

I think you get the point. The comonality between all of thesee pages looks like this;

1. Ideal conditions are required (both road and vehicle)
2. Drivers must be trained/knowledgeable in use of the system
3. Stopping distance is not always reduced, but the steering advantage is hilighted.

The problem with light cars (a very large number of consumer purchased vehicles lately) is that they don't have the weight to keep the skipping wheels on the ground, thus dramatically reducing the efectiveness in both stopping distance and steering control, hence the reason for removing them from the likes of the Cavalier and Sunfire.

Especially in snow, gravel, and sand (loose pack) ABS will drastically increase your stopping distance (by about 200% in some cases, depending on speed and density of the material you're driving in). The plow effect by your car's tires slows the trajectory of your vehicle.

ABS isn't designed to reduce stopping distance, it is designed to give steering control. These are two VERY different things. Incidentally, locking your tires and knowing how to change directions can/will significantly reduce your stopping distance with the same amount of control, as anyone who's ever taken or instructed a crash course will tell you.

I've conducted 80KM/h tests myself, in snow (loose and hard packed), gravel, sand, and wet and dry asphalt and under many of the conditions, especially the non-ideal driving conditions, my stopping distance was increased. I will grant you that my tires did suffer more on the locking tests, but if I'm making an emergency stop, I'd much sooner replace some tires than find myself face-first in the side of an SUV/Minivan/truck/etc.

BTW, speaking of ideal conditions; This study hilights another problem with ABS - Driver reaction time and leg strength. Many (most?) women and smaller men have great difficulty in putting 100lbs pressure on their brake pedals in a real hurry, which the NHTSA has discovered increases stopping distance (150-200lbs is the desired pressure, which was difficult to attain, except by the TRC (professional) test driver).