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Antilock-breaking (ABS) vs Stabilty Control (ESP) vs Traction Control Video
mouser:
Anyone have other good instructional driving videos (for beginners):
Here's a series that I just found that I like:
https://www.youtube.com/channel/UCB24MShZp8LkbV7FbA5BZAA/videos
TaoPhoenix:
Tough call here.
Driving reflexes are a bit tricky, and if two types of vehicles "encourage" opposite styles of driving like this whole ABS discussion, that feels tricky. I don't know what to think. I'm only a mediocre driver, and in an emergency I don't think I'm fast enough to figure out which of two braking reflexes I should be using!
IainB:
When ABS kicks in you can feel the system pulsing. That pulsing is the system's way of telling you that you need to back off the brakes a bit to maintain traction
--- End quote ---
This is the only part of your post I would take issue with...
-mouser (June 10, 2014, 07:28 AM)
--- End quote ---
That all looks like a gross misconception - potentially dangerous too.
ABS works simply by momentarily relieving hydraulic brake pressure to any wheel where the relevant sensors feed back to the control system that the wheel is about to stop rotating (i.e., lock up) when the car is in motion. Thus, no matter how hard you slam on the brakes, the wheels will not (theoretically cannot) lock up, and hence the pulsing sensation.
From memory, the first "production" car to have ABS fitted was probably the very up-market and (then) revolutionary 1965 Jensen FF, which had a torque-split LSD (limited slip differential) four-wheel drive system (based on racing car tested systems), was fitted with four-wheel disc brakes and the Dunlop-Maxaret antilock braking system (which was based on aeronautical systems).
In terms of road safety, ABS was arguably one of the most important modern developments for potentially significantly reducing the incidence of accidents. It seems a crime that it is still not fitted as a compulsory standard on all modern road-going vehicles, large and small.
LSD 4WD systems would not be far behind in importance.
SeraphimLabs:
When ABS kicks in you can feel the system pulsing. That pulsing is the system's way of telling you that you need to back off the brakes a bit to maintain traction
--- End quote ---
This is the only part of your post I would take issue with.
I am no expert, but the experts seem to be pretty consistent in saying that if you have ABS, and you feel it kick in during a hard/emergency breaking scenario, you should *NOT* ease up on the breaks or "tap" the breaks as you were taught in the non-abs days.
In such emergency breaking, apply consistent pressure and let the ABS do it's job.
Perhaps a better way to say what you were trying to get at is that ABS should only be kicking in during "emergency" breaking; if you are using your breaks in a way that is triggering ABS, and it's not an emergency -- then you are driving badly -- and you should take it as a signal that you need to change your everyday breaking habits.
-mouser (June 10, 2014, 07:28 AM)
--- End quote ---
You've pressed the brake, commanding the car to try and stop. But you've pressed so hard that the brakes locked up, triggering a skid. ABS senses that the wheel is sliding and reduces the brake pressure some to get it turning again in the interest of maintaining control. But then once the wheel is turning again the ABS clamps back down- making it skid again and repeating the cycle resulting in the pulsation and noise associated with the system. When that pulsation happens you are skidding your tires, resulting in a loss of traction and shortened tire life.
The correct response when you feel the ABS pulsing is to back off the brake slightly in order to preserve traction while still applying braking force. That way your wheels stay turning rather than breaking traction, but you are still applying very nearly as much braking force as road conditions will allow. In a panic braking situation the ABS intervenes to attempt to maintain traction, resulting in a far shorter stopping distance than what a skid would result in because of the increased control and keeping the wheels turning while braking.
I do like some of the traction control systems out there while driving. It is nice in slick conditions to avoid unwanted spins during acceleration. Haven't really put any of them to the test while braking though, nothing I drive is new enough to have that level of integration. But the classic Positraction differential, and the newer limited-slip centers really are worthwhile if free of mechanical defects. Its likely that the electric assists found in newer cars would have similar results in bad weather.
mouser:
The correct response when you feel the ABS pulsing is to back off the brake slightly in order to preserve traction while still applying braking force.
--- End quote ---
Not to beat a dead horse, and again, i am a complete non-expert in driving, but I do think these instructions for what to do when ABS kicks in are in direct contradiction to widely agreed upon advice.
But again, this may be a result of not qualifying your advice.
I think it would be useful to separate the two scenarios of importance.
SCENARIO ONE - AN EMERGENCY STOP WHEN YOU NEED TO BRAKE AS QUICKLY AS POSSIBLE
*THIS* is the scenario that most experts are talking about. In such a case, you, the above-average-but-not-super-human driver *CANNOT* outperform the ABS computer. In such a case, you should depress firmly and ALLOW THE ABS TO PULSATE AND DO ITS JOB. In such a case you do *NOT* want to be EASING UP on the brake -- that will prolong your stopping distance. And you don't want to have to be trying to figure out in your brain how much pressure you should ease off while you are in a life or death panic and trying to steer around some obstacle. Press hard and firm and let the ABS do its job.
SCENARIO TWO - NON-EMERGENCY BRAKING
In this scenario, your advice about easing up on the brake when ABS triggers is fine advice. All you are saying is that the driver is triggering a skid or near-skid, and in a non-emergency scenario where you have plenty of braking distance, this is a sign that you are braking too hard.
More info:
* http://www.tc.gc.ca/eng/motorvehiclesafety/tp-tp13082-abs2_e-215.htm
* http://www.nsc.org/news_resources/Resources/Documents/Tips_for_Driving_with_ABS.pdf
* http://www.icbc.com/about-icbc/newsroom/Documents/anti-lock.pdf
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