It's been more than a year since gas prices soared above the $4 per gallon mark and fell back to earth, but Americans are still trading their way out of their large cars.  A pair of new studies show that this trend has taken hold particularly among those who drive luxury cars. 

Autoblog reports, "According to a new study...fewer premium buyers are moving up and more buyers are actually moving down."  As recently as 2006, according to a study compiled by the Power Information Network, nearly 16% of new car buyers moved up, trading in a compact car to buy a midsize.  "But through the first half of this year, only about 11% did so. And compared to 2006, this year two other categories showed 4% gains: people moving from large to mid-sized cars, and those moving from mid-sized to compact cars."

A second study showed similar results.  Motor Authority reports, "According to a study by J.D. Power and Associates, the trend of luxury buyers trading in their full-sized cars for their mid-size siblings has increased from 12.6 to 16.2 percent over the last three years, while those going from mid-sized to compact premium cars have increased similarly from 10.8 to 14.8 percent." 

What's the reason behind the trend?  Autoblog speculates, "Customers don't want to look like they're flaunting their money, or they simply don't want to spend it. Even brand-loyal buyers are either keeping their cars, or instead of buying new ones they're going for pre-owned certified or an off-lease deal."  Motor Authority adds, "The economy is surely to blame, as people are simply finding ways to cut back while still maintaining their standard of living as well as possible."

We think that trends in automotive design - the line between midsize and large is blurring.  The 2010 Audi A4, for instance, is classified as a midsize car.  The 2010 Audi A6 is classified as large.  Compare footroom, headroom, shoulder- and hiproom, however, and you'll never find more than 3 inches difference between the two cars.  Just 1 cubic foot separates their cargo volume.  Content is blurring between cars as well.  It is possible to buy an Acura TL with nearly identical equipment to that found on the top-of-the-line Acura RL - but for nearly $10,000 less.

If you're in the market for a new car, check out the U.S. News rankings of this year's best cars as well as this month's best car deals.