Even though the price of gas is down, fewer Americans can afford to drive like they did even a year ago.

Yes, the YoY trend in decreasing mileage (MoM) appeared about Q2 2006. I scanned the tabulated data -- April 2005-2008. (An interesting note: contrary to MSM theater, summer holiday months, May-June, report the least total vehicle miles travelled in any one calendar year.) So I tend to rule out the relative spike in pump price (Jan-Aug 2008) being the proximate and a determinative cause of Aug rate change reported. Of course, someone would compare YoY pump price(s) to mileage to argue correlation to aggregate consumer purchasing and transportation preferences. (That will not be I :)

Diversity is the key to economic and political evolution.