Autolycus wrote:

"The Natural Philosopher" wrote in message
...
dennis@home wrote:
"The Natural Philosopher" wrote in message
...

If people were prosecuted not for speeding, but for HAVING
ACCIDENTS. the roads would be a far safer place.

Or *both*.
Not really. There is no direct correlation between vehicle speed
(within broad limits), and accidents.

If this is indeed true (and I'd need rather more than repeated assertion
to convince me), then is there one between vehicle speed and severity of
accident? Hint: m/2*v**2


No. There is a correlation between severity and peak *deceleration*.

That depends on how long it takes to stop the projectile.


In a well belted in passenger, up to 10g no damage. 10-50g minor
contusions. 50-150g probably broken bones,but survivable, over 150g,
probably internal organ damage, and above about 300g, at least 50%
chance of fatality.

Say you take 100g as a nice upper limit. Shaken, badly bruised, cracked
ribs, a bit of concussion, but still alive.

That 3200 feet per second squared

Given that stopping distance is v squared over 2a, consider a car
stopping in - say - the distance of its crumple zone..say 5 feet.
5=v squared/6400..for 100g decelaration.
V comes out to 178 feet per second.

About 120 mph.

So a head on to a concrete wall in a car with a well designed 5ft
crumple zone and rigid passenger cell and a well strapped in passenger
at 120mph is easily survivable.

As evinced by any motorsport accident analysis. I've personally seen a
mini - race prepared - do just that a bit shy of 90mph and the driver
walked away..

Nelson Piquet's final accident was estimated to peak at over 250g. He
broke his legs, but lived. Nigel Mansells Indy car accident was similar.

It's a different story where pedestrians are involved..they do not come
equipped with 5ft crumple zones.

If you are going to crash, try and make it head on, where the crumple
zones and the headrests and airbags will protect you..whiplash will
break your neck in a side impact..