Automotive market intelligence firm Polk expects US auto sales to rise 6.6% in 2013 over 2012 levels – reaching 15.3 new light-duty vehicles sold. North American production volumes are expected to increase to about 15.9 million units, which could be a 2.4% increase over 2012. These are signs that auto industry is continuing to recover, and it’s also a positive sign for the American economy, the company says.