Your outraged editorial (Dec. 23) about the 55 m.p.h. speed limit missed the point pretty badly, but then so do most articles about risk. (And this has nothing to do with the fact that Congress was swayed by the fact that the limit is vastly unpopular, and we are a democracy--a point you chose to overlook.)
The real point is that there cannot be a world without risk, so the only meaningful question anyone can ask is whether the risk is too high for what we get out of the risky activity. Of course the fatality rate goes up with increasing speed, as it does with many other factors. If you really want to reduce the toll by reducing speed, why not go to 45 m.p.h., or 35, or 15--very few casualties are likely at 15 m.p.h. People do value their time, which is why there was such a hubbub about 55 m.p.h. (which was, incidentally, enacted to save gasoline, not lives). Think of what would happen if you tried for 45, even though, if it were possible to enforce it, it would definitely save lives.
So what is the value of the time lost by lowering speed limits? (People become pariahs for making the calculation I am about to make.) The death rate on the highways is about one per 100 million passenger-miles, and let's suppose it's the same on the interstates we're talking about. At 65 m.p.h., 100 million miles take 1.54 million hours, while at 55 m.p.h. they take 1.82 million hours. If the fatality rate at 65 m.p.h. is (say) 25% higher than at 55 m.p.h., the lower speed limit is costing us about 1.4 million hours for each life saved. At the new minimum wage in California, that adds up to a cost of over $5 million per life saved, and remember that the minimum wage is a low estimate for the value of the average driver's time. That cost isn't fictitious--it comes out of productivity, and nothing is free, not even safety.