"PeterE" wrote in message
...
W K wrote:

Note that if you said PeterE's statement could be considered as
anti-car trolling.
It means that its possible that going 10% over the speed limit could
increase danger.

I've never disputed that in broad terms there is a correlation between
speed
and risk.

I realise that. Its the more extreme elements that would go all silly about
that one.

But what I've argued is that it isn't a steady linear or geometric
progression, it's more in the nature of a Z-curve, where risk rises very
rapidly between 0 mph and speeds where collisions may prove lethal, then
flattens out over a range of "safe speeds" where it is possible to stop
within one's field of vision, and then rises rapidly once the maximum safe
speed is exceeded.

I don't think that middle part is completely flat.
Because of:
a) unusual, unexpected, or bizarre events where an object/person/vehicle can
arrive in one's field of vision, causing a collision.
b) the effects of anything unusual at the various speeds (ie less risk of
injury if the unexpected becomes an accident, easier to get out of
difficulties).
c) An effect of statistical mush - if you overlay similar but slightly
different conditions into one definitions, you have to overlay and average
out those Z- curves until you get something with more curved boundaries.
ie - road X on a clear sunny day might have the Z point at 40 mph - yet
various other factors might shift that between 30 and 50 for different cars
or subtly different circumstances.