While President Obama’s initiative for a significant reduction in vehicles’ fuel consumption and CO2 emissions may sound very ambitious to some, a new study by the University of Michigan Transport Research Institute shows that car manufacturers have managed to improve their new cars’ fuel economy by 3 mpg in the last four years.

If this doesn’t sound a lot, then consider that according to the study, the average fuel economy of all 2012MY light vehicles available on the U.S. market is 21.5 mpg US (10.9lt/100km). That’s a far cry from the 54.5 mpg US (4.3lt/100km) target set for 2025, but still an impressive 14 percent up or +3.0mpg from 2008MY’s average of 18.9 mpg US (12.5lt/100km).

The study’s authors, Brandon Schoettle and Michael Sivak, chose 2008MY as the starting point because that’s when the EPA changed the methodology for calculating fuel consumption. They included all vehicles in the U.S. market except those made by Bugatti, Mahindra & Mahindra, Roush Performance, Saleen Performance, Shelby American, Spyker, Tecstar and Vehicle Production Group.

The improvement in fuel economy is attributed to the fact that the rising gas prices along with the economic downturn have made a large number of buyers become interested in more fuel-efficient vehicles.

Diesel powered models improved by 9.8 mpg on average, while America’s favorite gasoline engines lagged behind with a 2.6 mpg improvement in fuel economy.

Automatic and manual transmission models showed similar performance gains (+2.5 and +2.8 mpg respectively), while front-wheel drive models improved the most (+3.4 mpg, from 22.9 to 26.3 mpg) and rear-wheel drive ones the least (+1.2 mpg, from 17.2 to 18.4 mpg), with all-wheel drive vehicles falling in the middle (+2.0 mpg, 17.1 to 19.1 mpg)

Station wagons were the passenger cars with the largest increase in fuel economy, going from a 21.9 mpg average in the 2008MY to 26 mpg in the 2012MY. On the other side of the spectrum, full-sized vans improved the least in the last four years (+ 0.2 mpg).

Surprisingly, hybrids’ fuel economy did not improve over the last four years. The study found that while conventional-vehicle fuel economy improved each year gaining 2.6mpg from 2008 to 2012, hybrids lost an average of 3.0 mpg. However, hybrids generally return better overall fuel economy when compared to conventional vehicles (in 2012, 25.2 mpg versus 21.4 mpg, respectively).

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