Autolycus wrote:

"The Natural Philosopher" wrote in message
...
Autolycus wrote:

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

This takes a very narrow view of "severity" and a very tightly-defined
accident. In real life, cars don't always run head-on into concrete
blocks: they hit odd shaped objects with strangely projecting bits at
funny angles, and they do things like flipping onto their roofs if
certain dynamic criteria are met. If my car runs into a road sign at 10
mile/h, I'll probably survive, as I probably would at 40 mile/h. But
which would be the more severe accident?

An imperfect, inattentive, or foolish driver (obviously not a reader of
this group) suddenly realise you are stationary, in front of him and
100ft away when he starts braking. At 48 mile/h, he taps your back
bumper: at 55 mile/h, he's still doing 25 mile/h when he hits you. Which
is the more severe accident?



Depends..on many things.

I've come upon a rover in a ditch that lost it at 125mph (police
estimate, with which I agree..I got up to 110mph myself to check that
bend, and it was fully takable at that) and the front seat passengers
crawled out..the rear seat passengers who were not wearing seat belts,
were pretty badly knocked about..broken bones and multiple lacerations.
They all lived tho..

So accident severity is something that is only vaguely correlated to
speed..one person I knew years ago, found himself faced with a head on
collision with a wall on a motorbike,.. He decided to go out in a blaze
of glory and opened it up wide..in fact he flew over the top of the
wall, knocked himself out and broke an arm and a collar bone. At less
speed he would have been dead.

To an extent, high speed accidents are seldom one thump. They are
rolling tumbling events which bleed speed off progressively.

Its probably better to smash through a brick wall at 100mph, than come
to a dead stop doing 40mph, but it depends on so many factors.

The old experiment of pushing a candle into a piece of wood comes to
mind. It crumples. Fired from a gun, the candle goes right through the
board undamaged..

I am not advocating unlimited speed, just that fixed speed limits are a
poor way of achieving road safety. Driver experience and education is
the only solution. The downside of speed limits is they make people who
keep to them excessively smug and self righteous, and never likely to
question their own behaviour..as can be seen in many posts here.