willard west

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Question
Last evening as I was driving home just after dark a deer ran out across the road in front of me. I absolutely can't remember a time when I laid on the brakes any harder than I did last evening. Afterward I was surprised that the pedal didn't break off. The good news is that the RX300 stopped without hitting the deer. Well, maybe the bumper grazed her butt a little bit, but both my wife and I agreed that she wasn't likely hurt at all.

I was very impressed with the braking action, the RX just squatted and "growled" to a quick and sure stop. Both of us assumed the "growling" was the result of the ABS kicking in.

Which brings up my question.

Has anyone thought about activating the ABS ONLY if the VSC indicates the vehicle is not tracking correctly?

I was on dry concrete pavement last night and I came away not being quite sure that I wouldn't have stopped a mite quicker if the ABS had not interfered. I know that the VSC yaw sensor is very likely much more sensitive to yaw than is my own "behind", but I did not have any sense at all that the vehicle was deviating from a straight line stop. It would be my guess therefore that the ABS activation in this case was needless.

Since the primary purpose of ABS is to allow me to maintain directional control of the vehicle would it not be a good idea to let me have full and complete control of the braking action unless the vehicle is deviating from the desired "track"?

Or is it even possible to change the ABS braking algorithm such that it allows more severe braking unless or until the VSC over-rides it?

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mooretorque

Willard, as I recall, the only predictable circumstances where a vehicle would stop quicker w/o ABS than with were situations like gravel or loose snow when a cushion of road material could build up in front of a locked wheel. As you know, the idea behind ABS was to allow anybody to be able to (essentially) threshold brake, rregardless of conditions, since the coefficient of static friction is always less than that of dynamic (rolling) friction (with exceptions mentioned above).

You really think you'd have stopped faster with 'em locked up??

willard west

According to IIHS testing in almost all conditions, but especially so on an ice rink, Locked braking wheels brought the vehicle to a quicker stop than ABS.

I think the problem might be with the fact that ABS is a compromise, the system can only turn the brakes "FULL OFF" or allow them to be fully applied, and yes this will happen about 10-20 a second, but what is the average of a squarewave?

It can never add up to true threshold braking.

The current statistics aer indicating an abnormally high rate of single vehicle accidents with ABS than without, but no one yet knows why this might be. But the overall result is that statistically we are better off without ABS than with.

mooretorque

I had read at least some of that data, too. Pat Bedard of C&D did a column about this very subject around two years ago. Had not read the IIHS stuff, but Bedard, esp, has been critical of their objectivity in the past. He does seem a bit paranoid at times, I'll grant you.

Square wave analogy is a good one........I'll have to do some more cipherin'.

BTW, glad you didn't have to tag one for Game & Fish. Certainly wouldn't have done the RX any good. And unplanned rally driving usually not too healthy, either.