Volkswagen Passat
A newly available turbocharged diesel that gets 43 mpg highway accounts for the VW Passat's appearance on the most-improved list. And the Passat TDI can go up to 800 miles between fill-ups. Overall fuel economy in the Passat is up 24% over 2008. Volkswagen Passat

Volkswagen AG (Frankfurt: VOW) U.S. sales grew 28.4 percent in May, the company's best May since its heyday as a 70s era-icon.

Wolfsburg, Germany-based VW sold 38,657 cars in the U.S. during May, over a quarter of which were of its award-winning Passat model. May was the best month ever for Passat sales. The VW volume leader remained the Jetta which sold over 15,000 units. The Beetle, boosted by a fresh redesign, had its best May since 2002.

VW's U.S. May sales were referred to as a significant accomplishment by the company's U.S. president and CEO, Jonathan Browning. Volkswagen AG (Frankfurt: VOW) shares fell 3.41 percent to €117.55 ($145.32) Friday.

Volkswagen Germany Germany Volkswagen