Re: Re[2]: Dose vs Regs cont'd

[Kent Edwards <EDWARDSRK1@padvx2.a1.ornl.gov>]

The phase "Speed Kills" is catchy and has been used by law enforcement for 
years and in a way it may be partially true.  But is it pure speed that kills 
or a byproduct of it, vehicle density?

The statistical probability of having a two car collision is exactly the same 
whether the speed is 55 or 65 if only one car is on the road.  The probability 
will of course increase as the vehicle density increases.  If two structurally 
identical highways with the same destination had speed limits of 55 and 65 
which one would be worn out first?  Most probably 65 mph would.

I do not know whether or not "traffic fatality" data is normalized to traffic 
density but it probably is not since the stats are given in raw numbers and 
not as rates.  The point is that data can be used to say anything the purveyor 
wants it to.  Be weary, keep that analytical edge.

Kent Edwards

Ditto all disclaimers