The Department of Transportation's Federal Highway Commission has released the latest report on Traffic Volume Trends, data through September. Travel on all roads and streets changed by -1.5% (-3.6 billion vehicle miles) for September 2012 as compared with September 2011. The 12-month moving average of miles driven increased a tiny 0.27% from September a year ago (PDF report). And the civilian population-adjusted data (age 16-and-over) has set a new post-financial crisis low.

Here is a chart that illustrates this data series from its inception in 1970. I'm plotting the "Moving 12-Month Total on ALL Roads," as the DOT terms it. See Figure 1 in the PDF report, which charts the data from 1987. My start date is 1971 because I'm incorporating all the available data from the DOT spreadsheets.