How Get Shortest Braking Distance on Ice With ABS?

[nleksan]

I love the irony of winter, in that every time it snows, the only cars I see in ditches are SUV's.

Just remember that everyone thinks they're a good/great driver, and remind yourself that you aren't (I am not, no way... I say this even with countless track miles, numerous victories, and what not, because I am still learning, and I can get in the passenger seat of some drivers' cars and be equally amazed at their talent and in need of new pants).
The best way to drive safely is to assume (usually correctly) that everyone else is an idiot, and that you are overconfident. Or, keep reminding yourself that you are too confident.

Just my opinion...

 

[morris]

sooooooooo. why are we even on ice? you started with 2 strikes against you.

 

[DBMaster]

^My original point, exactly. The best braking strategy for ice is to avoid driving on it. Around here, I have never had a compelling reason for intentionally doing so and, if I ended up doing it, I wished I hadn't. There is far too much variability in how other drivers deal with it. I suppose if you live in an area with less traffic you may be able to play around - like I could 25 years ago. And, we have very few days in a year in which ice is a factor. So, my "vast" accumulated wisdom tells me that, when the roads become a skating rink, stay home. YMMV.

 

[Bamaro]

1.

 

[Norm Olt]

If you happen to stop in time, make sure they guy in front of you acknowledges the correct number of impacts after you get hit in the rear by the car (or cars?) behind you...

i.e., 3 cars, you in the middle, guy in front feels one impact, you were stopped and hit into him by #3.

or, 5 cars, you #2, three impacts to guy in front of you means #3 hit you, was hit in turn by #4 and then #5.

Either scenerio, you and guy in front s/b in the clear, liability-wise.

Cheers!

 

[eljefino]

Originally Posted By: Cujet
There are some significant brake bias differences in some modern ABS equipped vehicles. Front and rear brakes may have more similar initial torque. Due to these differences, the rear brakes have more initial stopping power than conventional older vehicles. These cars and trucks will sometimes rely on the ABS to prevent rear wheel lockup before the fronts even think about losing traction.

This gives a nicer braking feel to many cars.

Experienced drivers will notice that only modest ABS engagement is in play, and the fronts are not yet at the threshold limit. Much of this depends on tire compound, road conditions, vehicle loading and weight transfer.

This means that under some circumstances, threshold braking may not be the fastest deceleration rate.


Not sure how this translates to stopping on glare ice. And, better vehicles are tuned to reduce ABS authority at very low speeds. Allowing modest wheel lockup for snowy conditions.


Hit some glare ice on my non-ABS saturn with generic winter tires. Had the fronts lock up first and started skewing towards the ditch. I'd call it an understeer except I never initiated going that way.

My answer was yanking the e-brake to get the rears involved also. Seems my brake bias is calibrated to having more friction so I get some nose-dive and weight transfer. I've been into my rear brakes last fall and they work as designed, are free, adjusted, etc.

All this to say, if you get some ABS, it may, counter-intuitively, be worthwhile to really stomp on it to get ABS on *all* wheels, so you can scrub off more speed.

Steering is something that should be attempted after losing as much speed as possible. I'll assume it's into something that's the lesser of two evils.

In my example, a red traffic light, traction improved, though my driving did not. I stopped in time.

 

[SubLGT]

Originally Posted By: SubLGT
If you have a car equipped with winter tires and ABS, which braking technique will give you the shortest braking distance on ice:

1. Stomp on the pedal, and let ABS do all the work?
2. Push lightly on the brake pedal until ABS comes on, then back off slightly until ABS disengages?
3. Push lightly on the brake pedal, but do not allow ABS to activate?


I spent an hour with google looking for an objective test of different braking techniques on ice with ABS and surprisingly found nothing. I seem to remember Car & Driver (or Motor Trend?) doing such a test a few years ago, but google turned up nothing.

 

[Garak]

From a physics standpoint, threshold braking will be it, and that applies on any surface. The only exception is under certain circumstances, gravel, sand, snow, and the like can wedge up ahead of a sliding tire's contact patch and cut stopping distances.

 

[opus1]

Originally Posted By: Garak
From a physics standpoint, threshold braking will be it, and that applies on any surface. The only exception is under certain circumstances, gravel, sand, snow, and the like can wedge up ahead of a sliding tire's contact patch and cut stopping distances.
^ ^ This. The intent of ABS is to allow the driver to try to steer and keep the vehicle in some semblance of control, not to shorten the distance. And in the cases above, you're better off in a non-ABS car to let the material wedge build up and help you stop.

 

[Garak]

There have been tests, notably on gravel, that ABS can significantly increase stopping distances. On gravel, of course, with ABS, you can't wedge up the material, and we all know how unpredictable gravel can be otherwise.

Generally speaking, ABS has been a good thing. It has improved since its introduction, and even since it was widely rolled out.

 

[gofast182]

Even with ABS, try to keep your wheels straight if possible. Tires can almost always do ONE thing well but you have to pick that one thing: cornering or acceleration or braking. Introduce a second thing and all bets are off.

 

[supton]

Originally Posted By: morris
sooooooooo. why are we even on ice? you started with 2 strikes against you.


Ice happens.