Lewis–Mogridge Position

The Lewis–Mogridge Position, named after David Lewis and Martin J. H. Mogridge, is a maxim in urban planning that states “traffic expands to meet the available road space”. The position points out the relative futility of building more roads to deal with traffic, as the gains are erased within a matter of weeks to months when people drive more because of the available space.
by Jason Fitzpatrick via How-To Geek