Everyone who writes safety critical software should read this

[Chris]

On Thursday, 31 October 2013 at 19:45:17 UTC, Walter Bright wrote:
> 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.

I still think that, although software can help to make things 
safer, common sense should not be turned off while driving. If 
it's raining heavily, slow down. Sounds simple, but many drivers 
don't do it, with or without software.