Well....
http://www.wired.com/2014/06/wuwt-tr...nduced-demand/

"The concept is called induced demand, which is economist-speak for when increasing the supply of something (like roads) makes people want that thing even more. Though some traffic engineers made note of this phenomenon at least as early as the 1960s, it is only in recent years that social scientists have collected enough data to show how this happens pretty much every time we build new roads. These findings imply that the ways we traditionally go about trying to mitigate jams are essentially fruitless, and that we’d all be spending a lot less time in traffic if we could just be a little more rational."