I've always been fascinated by the concept of risk-reward in public safety: How much risk is acceptable in order to maintain efficiency and productivity?

You've seen it over and over. At a certain intersection in a certain town, there'll be an unfortunate accident. A child is hit by a car.

So the public cries out, the town politicians band together, and the next thing you know, they've spent $60,000 to install speed bumps, guardrails and a stoplight at that intersection - even if it was clearly a accident, say, a drunk driver, that had nothing to do with the design of the intersection.

I understand the concept; people want to DO something to channel their grief. But rationally, turning that single intersection into a teeming jungle of safety features, while doing nothing for all the other intersections in town, in the state, across the country, doesn't make a lot of sense.