An interesting discussion on NPR. Take a listen.
"...For decades, urban areas across the country have been adding lanes and building roads in an effort to fight congestion, but a recent study by the University of Toronto says that these tactics aren't actually all that effective.
The study looked at the largest metropolitan cities in the U.S. and found that widening and building more roads actually creates more traffic."
To listen to the full discussion on NPR click here: http://www.npr.org/2011/07/09/137708751/more-roads-may-pave-way-to-more-traffic