In 2009 onderzochten twee economen de hoeveelheid nieuw gebouwde wegen en het aantal gereden kilometers in verschillende Amerikaanse steden. En wat bleek:

If a city had increased its road capacity by 10 percent between 1980 and 1990, then the amount of driving in that city went up by 10 percent. If the amount of roads in the same city then went up by 11 percent between 1990 and 2000, the total number of miles driven also went up by 11 percent.

Het uitbreiden van openbaar vervoer-opties lijkt niet te helpen bij  het terugdringen van het aantal gereden auto-kilometers:

You might think that increasing investment in public transit could ease this mess. Many railway and bus projects are sold on this basis, with politicians promising that traffic will decrease once ridership grows. But the data showed that even in cities that expanded public transit, road congestion stayed exactly the same. Add a new subway line and some drivers will switch to transit. But new drivers replace them. It’s the same effect as adding a new lane to the highway: congestion remains constant. (That’s not to say that public transit doesn’t do good, it also allows more people to move around. These projects just shouldn’t be hyped up as traffic decongestants, say Turner and Duranton.)

Maar gewoon het aantal wegen verminderen werkt wel. 😈

(via @BrentToderian)