This is an update of a chart from two earlier posts. Although there was a slight uptick in 2013, the VMT (vehicle miles traveled) trend continues to be essentially flat. From the 1930s until recently, with a few interruptions, VMT in the U.S. grew consistently. The inflection point in the curve appears to be around 2004, when the price of gasoline rose above $2.00 per gallon. The current period of flat VMT is the longest since WW II, when gasoline was rationed. VMT are strongly correlated with economic activity. For more on the economic aspects of the recent VMT trend, and a discussion of the likelihood that constraints on the global supply of petroleum are involved, see a recent presentation at Columbia University by energy analyst Steven Kopits.