Have you ever wondered why people do the things they do? Why people would sleep-in for twenty more minutes then franticly speed off to work? Why people will buy ten items for ten dollars at a store promotion, when a week earlier that same item cost a dollar?
As you think about that consider this. In Fairfax Virginia they installed some intersection cameras to catch drivers in violation of running red lights. Research showed according to the article entitled "Camera use deters red light running in Virginia community", in the Status Report for Highway Safety. Red light violations dropped by 44% in the first year the cameras were installed. Similar results were shown in Oxnard California with a 42% drop in red light violations with the introduction of intersection cameras. That's not even the interesting part. Research also showed that in both cities, they experienced a halo effect on other intersections that didn't exhibit intersection cameras and red light violations on those dropped by 34%.
So what does that mean to you and I? Well it's now safer to drive in Fairfax Virginia and Oxnard California, but to an economist its more than that. This is statistical evidence that people respond to incentives. In abiding by the law to not run red lights. That incentive was so strong it caused the same behavior to be exhibited at other stop lights not adorned with cameras. So if the incentive is strong enough, you could get a population to do just about anything.