The Road...Less Traveled: An Analysis of Vehicle Miles Traveled Trends in the U.S. from the Brookings Institute is "an analysis at the national, state, and metropolitan levels of changing driving patterns, measured by Vehicle Miles Traveled (VMT) primarily between 1991 and 2008, reveals that:
Driving, as measured by national VMT, began to plateau as far back as 2004 and dropped in 2007 for the first time since 1980. Per capita driving followed a similar pattern, with flat-lining growth after 2000 and falling rates since 2005. These recent declines in driving predated the steady hikes in gas prices during 2007 and 2008. Moreover, the recent drops in VMT (90 billion miles) and VMT per capita (388 miles) are the largest annualized drops since World War II."