I've been interested in risk theory for several years since I read a study at the CATO institute. Smithsonian Magazine has an article on it worth reading. (via Instapundit)
This counterintuitive idea was introduced in academic circles several years ago and is broadly accepted today. The concept is that humans have an inborn tolerance for risk—meaning that as safety features are added to vehicles and roads, drivers feel less vulnerable and tend to take more chances. The feeling of greater security tempts us to be more reckless. Behavioral scientists call it "risk compensation."
There has been a lively debate over risk compensation ever since, but today the issue is not whether it exists, but the degree to which it does. The phenomenon has been observed well beyond the highway—in the workplace, on the playing field, at home, in the air. Researchers have found that improved parachute rip cords did not reduce the number of sky-diving accidents; overconfident sky divers hit the silk too late. The number of flooding deaths in the United States has hardly changed in 100 years despite the construction of stronger levees in flood plains; people moved onto the flood plains, in part because of subsidized flood insurance and federal disaster relief. Studies suggest that workers who wear back-support belts try to lift heavier loads and that children who wear protective sports equipment engage in rougher play. Forest rangers say wilderness hikers take greater risks if they know that a trained rescue squad is on call. Public health officials cite evidence that enhanced HIV treatment can lead to riskier sexual behavior.
And think of the government regulations and spending that are supposed to make us safer.