Saturday, February 23, 2013

The unintended consequence of licence plate schemes

A couple of cities such as São Paulo, Bogota and Mexico City have already tried to cut down on traffic using licence plate schemes. Needless to say they have achieved limited success  if any .

In this Freakonomics episode Dubner and Levitt talk about the universal law of 'unintended consequence' and how it applies to such schemes.

2 comments:

Fabio Storino said...

Long time reader (one of my favorite blogs, BTW!), first time commenting. Even if people weren't gaming the system, such a scheme still doesn't make a lot of sense: a city has a relatively fixed "carrying capacity" for vehicles, while a license plate scheme deals with relative numbers of vehicles. As the city's fleet continues to grow (in São Paulo we're talking about a thousand new vehicles per day), in a few years congestion returns to the previous level.

Rafael H M Pereira said...

Thanks for the comment Fabio! You have a point there. But I was trying to put myself in the mayor's shoes. In a dramatic situation (as the observed with astonishing congestion levels in Sao Paulo), I think I would implement the license plate scheme as a desperate measure, even knowing this would only have short-term effects.