Global warming concerns, urban pollution and the expected end of the petroleum fuel supply were closer to the forefront of American consciousness in 2007 than ever before. While changes to America’s highly automobile-dependent infrastructure are nearly as slow as those to the environment, 2007 marked the highest single increase in fuel economy on record. In 2006, the fleet-wide fuel economy average for cars sold in the U.S. was 25.7mpg (9.15L/100km) but that number improved to 26.6mpg (8.8L/100km) in 2007.

Passenger cars averaged 31.2mpg while pickup trucks averaged 23.1mpg. Part of the improvement was fueled by a decline in sales of full-size SUVs, which are being quickly replaced by more efficient car-based crossovers. The improvement meant that on average, the industry exceeded its target under existing CAFE laws that required fleet-wide averages of 27.5mpg for passenger cars and 22.2mpg for trucks, reports The Detroit News. However, individual makers’ fuel economy numbers varied widely, with non-U.S. brands responsible for much of the improvement.

For example, GM averaged 29.9mpg for domestically-produced passenger cars, 31.9mpg for imported vehicles and 22.6mpg for light trucks. Honda, on the other hand, averaged 33.5mpg for domestically produced cars, 39.6mpg for its imports and 25mpg for light trucks. The now-defunct DaimlerChrysler was the worst performer, managing only 28.6mpg for U.S.-made cars, 24.7mpg for imports and 22.6mpg for light trucks.

Given the fuel economy achieved in 2007, it seems most manufacturers shouldn’t have a problem reaching the 2012 CAFE standards of 35mpg with their passenger car fleets. However, the CAFE calculations are made with light trucks included (with some loopholes, of course), which means that unless truck sales seriously decline, every manufacturer will have some serious work to do to meet the new regulatory standards.