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.
While total driving in both rural and urban areas grew between January 1991 and September 2008, rural and urban VMT have been declining since 2004 and 2007, respectively. Amongst these collective driving declines, the nation shifted more of its VMT share to larger capacity, urban roadways.
While all vehicle types increased their total driving from 1991 to 2006, passenger vehicles—specifically cars and personal trucks—consistently dominate the national share. This share dominance includes rural interstates, where combination trucks contribute a much larger share than they do elsewhere. Over time, however, passenger trucks produce a greater share of VMT due to their surge in registrations versus standard passenger cars.
Southeastern and Intermountain West states experienced the largest growth rates in driving between 1991 and 2006, while the Great Lakes, Northeastern, and Pacific states grew at a slower pace. These varied, but positive, growth rates reversed after 2006, as 45 states produced less annualized VMT in September 2008. Similarly, per capita driving declined in 48 states since the end of 2006.
Total driving on principal arterials is concentrated in the 100 largest metropolitan areas, but the greatest driving per person occurs in low density Southeastern and Southwestern metros. In addition, the 100 largest metros’ urban driving share exceeds the national share, with 83 metros carrying over 70 percent of their principal arterial traffic on urban roadways.
Amid the current recession and declining gas prices, drops in driving should continue, creating dramatic impacts in the realms of transportation finance, environmental emissions, and development patterns. Government officials and policy makers at all levels must account for these potential long-term consequences.