Everyone who writes safety critical software should read this

[Walter Bright]

On 10/31/2013 7:57 AM, H. S. Teoh wrote:
> You don't know how thankful I am for having learnt the concept of
> pumping the brakes, ABS or not. I'm afraid too many driving instructors
> nowadays just advise slamming the brakes and relying on the ABS to do
> the job. It doesn't *always* work!

Pumping the brakes is not how to get the max braking effect.

The way to do it is to push on the pedal to about 70-80% of braking force. This 
causes the car to push its weight onto the front tires and load them up. Then go 
100%. You'll stop a lot faster, because with more weight on the front tires they 
have more grip. (I think this is called 2 step braking.)

You lose about 30% of braking force when the tires break loose. The trick is to 
press the pedal just short of that happening, which can be found with a bit of 
practice.

The downside of just slamming the brakes on and letting the ABS take care of it 
is you lose the 2-step effect.

There are also cases where you *want* to lock the tires. That case is when 
you're in a skid and the car is at a large angle relative to its velocity 
vector. This will cause the car to slide in a straight line, meaning that other 
cars can avoid you. If you don't lock the wheels, the wheels can arbitrarily 
"grab" and shoot the car off in an unexpected direction - like over the 
embankment, or into the car that was dodging you. The car will also stop faster 
than if the wheels suddenly grab when you're at a 30 degree angle.

But yeah, I'd guess less than 1% of drivers know this stuff. And even if you 
know it, you have to practice it now and then to be proficient at it.