Despite ongoing efforts to wean itself off the teat of foreign oil, the U.S. car market is still almost twice as polluting as Europe and Japan. This new finding from automotive data provider, JATO Dynamics, comes despite the Car Allowance Rebate System (CARS) – better known as “cash for clunkers” – program that replaced over 690,000 vehicles on the roads with more fuel-efficient models and the fact that American consumers are significantly more inclined to adopt Hybrid technology than Europeans. Then why is it so?

JATO’s study of the U.S. light vehicle market in the first quarter of 2010 reveals that the market’s average CO2 output is 268.5 g/km. In order to reflect like-for-like comparison with car markets in other global regions, excluding pick-up trucks, full size vans and small commercial vehicles, the figure falls to 255.6 g/km. This figure compares very unfavorably to Japan (130.8 g/km) and Europe’s five biggest markets, which average 140.3 g/km.

All markets improved marginally when compared to the full-year average in 2009 with Japan’s CO2 output down 0.4 g/km, the USA down 1.0 g/km and Europe improving most significantly with a 4.3 g/km reduction in the year-to-date.

“It is still clear that American consumers need to undergo a fundamental re-think of their vehicle buying preferences, but the past period of economic upheaval is likely to have meant that other domestic issues have taken consumer’s priority”, says David Mitchell, President of JATO Americas. “The blame can’t just lie with consumers though, the OEM product offering in the US still does little to promote alternatives to the large engine capacity gasoline vehicles which still dominate the market.”

Gasoline, diesel and Hybrid cars

However, Americans consumers have taken a shine to Hybrids such as the Toyota Prius. Hybrids enjoy a 2.3 percent market share in the U.S., while in Europe it is still only 0.5 percent. Not surprisingly though, Japan leads the way with 10.1 percent of market share going to Hybrids.

While they mightn’t have embraced Hybrids as much as Americans, Europeans have been able to reduce their CO2 emissions thanks to the rising popularity of diesel, a fuel which has a 48.9 percent market share in Europe. Conversely, Japan has a tiny diesel share of only 0.11 percent, but its highly congested roads make very small and economical gasoline cars a popular choice. Currently, the U.S. market is dominated by gasoline which has 81.9 percent market share, with only 1.7 percent being diesel.

Fuel too cheap?

JATO sees cost as a major factor in the difference between the popularity of different fuels and fuel technologies in different countries. The price of gasoline still remains comparatively low in the U.S. when compared to other global markets where its rising prices have been one of the key influences for change. Of the vehicles sold in the U.S. 33.9 percent fall within a 15-20 mpg consumption bracket, compared with only 0.63 percent in Japan and just 0.29 percent in Europe.

Carrot or stick?

JATO says varying CO2-based taxation regimes that reward or penalize certain technologies can also play a part in regional variances. Japan’s high-technology driven economy favors new technologies such as Hybrid and electric vehicles, while European vehicle "scrappage" schemes have contributed significantly to the introduction of a large number of low polluting, fuel-efficient small cars – something that “cash for clunkers” didn’t do to the same effect.