A study from the Curtin University Sustainability Policy Institute says that many cities - including Vienna, Zurich, Atlanta, Los Angeles, and Houston--have already seen a decline in car usage between 1995 and 2005. Driving rates in the U.S. did, however, rise in 2010 by 0.7%, but the study's authors believe a number of factors could come together to decrease our overall car use: The first is that cities are hitting what's known as the Marchetti wall. Most people don't like having to travel more than an hour each way to work, and cities tend to not get larger than one hour via car in every direction.

Traffic engineers will need to fundamentally change their traffic models and their assumption that increasing road capacity is their main raison d’etre. Road diets and traffic calming will become the skill they need to lead with rather than being pushed into....Peak car use will generate a growing rationale for removal of high capacity roads and conversion of space to support transit, walking and cycling and the urbanism of the new city.