Asking all commuters to cut back on rush-hour driving reduces traffic congestion somewhat, but asking specific groups of drivers to stay off the road may work even better.
San Francisco Bay Area freeways colored according to how popular they are as connectors between other roads (bc) and the number of geographic areas that contribute to traffic on a particular road (Kroad).
The conclusion comes from a new analysis by engineers from the Massachusetts Institute of Technology and the University of California, Berkeley, that was made possible by their ability to track traffic using commuters’ cellphone and GPS signals.
This is the first large-scale traffic study to track travel using anonymous cellphone data rather than survey data or information obtained from U.S. Census Bureau travel diaries. In 2007, congestion on U.S. roads was responsible for 4.2 billion hours of additional travel time, as well as 2.8 billion gallons of fuel consumption and an accompanying increase in air pollution.