2009, The Netherlands. Some inhabitants of one Rotterdam’s neighbourhood receive a strange email: they have been watched while driving and are asked of not doing it any longer. Is it a threat or blackmail?
Absolutely not! The message comes for Rotterdam City and the company managing the highway that are allied to reduce traffic jams that has been polluting the cities day after day.
Wouldn’t it be easier to build bigger highways or built new ones?
Here comes the “Braess Paradox” . According to this theory, increasing the road capacity to reduce traffic jams would make the situation worse.
Actually, with a new road, people who have given up to the car before, would go back and use the car again. In addition, those who were avoiding using the car during the rush hours would try to do it again.

However, by eliminating roads, the journey time can be reduced, because some motorists will be inclined to abandon the car. This is the paradox.
Rotterdam City tries also another thing: the positive toll, also known as the reverse toll.
What is it? If the citizens leave the car into their garage during the rush hours, they will receive a small amount of money. Of course, they will receive also a device to control if they indeed have left the car into the garage.
It works! In a couple of years, the volunteers applying to that scheme increase and traffic jams decrease. Also when the money stop, people keep up with their good habit. Rotterdam starts to better breath.