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Mad Roger Mad Roger is offline
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Default Need help INTERPRETING these test results police cruiser SAE J866a Chase Test

On Sun, 14 Jan 2018 01:30:23 -0800 (PST),

I'm not sure how to extrapolate that information to stopping distances.

I would have thought that as long as the driver & brake servo can
apply enough force it would make no difference at all to stopping

Thanks for that observation as I'm trying to derive as much real-world
benefit from the police cruiser report as is possible given Clare's astute
observations about EE and FF pads faring differently, but not because of
their coefficient of friction.

There were 3 police tests over the decade, where only the penultimate test
aimed for uniform pedal pressure.

The middle test is the one that aimed for a given pedal pressu
a. 45-to-15mph at 10ft/s/s (approximately ~10 foot pounds +- a few)
b. 70-to-30mph at 22ft/s/s (approximately ~20 foot pounds +- a few)
c. 90-to-0mph at 22ft/s/s (approximately ~30 foot pounds +- a few)

Fundamentally, they said pedal pressure is, effectively, what a human does
all day every day - hence pedal pressure is, arguably, more important in a
well-used "cruising" vehicle that doesn't do panic stops consistently.

A targeted deceleration rate where pedal force is proportional to pad temp.

The other two studies were different.
1. Mostly stopping distance
2. Mostly pedal pressure
3. Mostly driver perception

In the end, the DOT edge code (AMECA edge code) is only slightly useful to
a consumer, I think. I wish it were more useful, but I've gleaned out of it
what I can, and that's the best any of us can hope to do.

I was hoping to get more insight from the scientific and mechanical folks