Paul Walker explains why the Law of Unintended Consequences takes hold of every new government programme, to the consternation of every policy-maker involved who's never learned the lesson:
[R]esearch has shown that people drive faster in vehicles that feel safer, attempt to bike on more dangerous terrain when they wear helmets and pay less attention to infants being bathed when the children are in seats that are said to reduce the risk of drowning...
When explaining these results Steven Landsburg asks, "If the seat belts were removed from your car, wouldn't you be more cautious in driving? ... Carrying this observation to the extreme, Armen Alchian of the University of California at Los Angeles has suggested a way to bring about a major reduction in the accident rate: Require every car to have a spear mounted on the steering wheel, pointing directly at the driver's heart. Alchian confidently predicts that we would see a lot less tailgating.
The fundamental lesson?
"[P]eople respond to incentives." And politicians and policymakers need to remember this when designing policy."