I love clever uses of incentives and tech: Cities are using traffic lights near schools that start red and turn green if an approaching car isn't speeding.
If you're good, you get to keep driving. If you're bad, you have to stop and wait for the light to turn green.
The average speed on the road almost immediately dropped to the speed limit as people learned the rules.
Instead of punishing people with tickets after the fact, it creates the behavior the city wants.