With ever increasing numbers of cars on the road, surely our air is getting more polluted, right?  Well not exactly, or so says Ben Lieberman of the Competitive Enterprise Institute, who notes that recent advances in auto technology are having a noticeable impact on our air quality:  “Recently EPA Administrator Mike Leavitt held a media event highlighting 17 new cars and SUVs that meet tough new emissions standards.  These new standards mean that your next new vehicle will be 77 to 95 percent cleaner than your current one, and up to 99 percent cleaner than a typical 1970s car or truck .   What this means is that total vehicle emissions could decline more than 80 percent during the next twenty years or so.”