In article , Larry Jaques says...

Doh! It appears that I missed that paragraph entirely. My suggestion
stands, though. ABS keep dumb drivers on the road and (hopefully) not
plowing into us.

Although, oddly, the SUV that ms. Over-the-Bridge was driving, probably
*had* ABS. And yet she still went in the drink. How can this be?

She was driving the biggest, heaviest, most safety-equipped car
you can buy nowadays. You can even *imagine* her loved ones thinking
'gee, I'm sure glad Ms O-t-B is driving a Humongo Exploder. They're
real safe."

So what happened?

She forgot she was driving.

She forgot that ABS does not *create* traction out of thin air.

She probably missed the fact that the road was slippery to start
with, because the active stability control was compensating for
the lack of traction. And the ABS was preventing the car from
skidding when she used the brakes most of the time.

She was on the damn *phone*.

She wasn't paying attention to what the feedback from her car was
telling her about the road conditions. Feedback like that's pretty
much been eliminated in cars today.

Systems that are designed to get drivers out of trouble, like ABS
and active traction and stability control have one big problem:
as long as they're working, the driver doesn't realize that
road conditions have deteriorated.

At some point the systems designed to help, run out of headroom
in their feedback circuits. There's no window between when the
brakes are applied, and the rotation sensors shows the wheel locked.
There's no region in the phase diagram for the traction control
to keep a wheel turning when it starts to slide.

And of course, the irony is at that point the driver has about zero
traction available to control the car.

This is why ms. O-t-B took a one-way trip down the fast elevator.

Jim


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