Stricter fuel-economy standards will gradually reduce the environmental impact of cars, but what if people just stopped buying them? New-car sales haven't yet recovered to their pre-recession levels, and at least one analyst believes that at best, they'll only equal those heights this year. The National Automobile Dealers Association says 16.4 million vehicles were sold last year, against 16.9 million in both 2005 and 2006, heights that were followed by several years of declines.