<snip>Remember the dreadded national speed limit of 55? That was beacuse of the perceived world oil shortage and opec's prices in 1974. Then in the 80s it became "55 saves lives". Of course it does. 25 saves a lot more. Then in 1986 when there was no more "oil shortage" the law was repealed, speed limits went gradually back up to where they were and the heck with saving lives.
IIRC there was some interesting journalism trying to find the increase in deaths that should have resulted from the increase in speed limits - because they weren't to be found in the raw data. Auto safety improvements (like air bags, ABS, etc.) and mandatory seat belt laws appear to have done more than the 55 MPH limit did.
When the 55 MPH limit was mandatory, one of the car magazines (I don't recall if it was Car & Driver or Motor Trend) ran a calculation of the number of lives wasted by the increase in "time spent gettin' there" by having to drive slower. They took the avg number of miles driven, calculated the increase in time spent driving due to slower travel speeds, multiplied by the driving population, and divided the resultant people-hours by the average lifespan in hours. The final figure was the number of lives being consumed entirely by driving slower. It was on a par with other junk science and used the same methods.