In four years’ time, every automaker in the U.S. will have to ensure that their fleet-wide fuel economy is 36 mpg or better under tough new 2016 Corporate Average Fuel Economy (CAFE) standards. 

But according to a University of Michigan study, the average fuel economy of new cars and light-duty trucks sold in the U.S. has only risen by 3 MPG in the past four years to an average economy of 21.5 mpg. 

Comparing the fuel economy of cars and light-duty vehicles on sale in 2008 to those on sale in 2012, the study concluded that some vehicle segments exhibited a better average gas mileage increase than others. 

Diesels Gained 9.8 Mpg, Gasoline only 2.6 mpg.

On average, the study found that 2012 model diesel cars were rated at 9.8 mpg better than comparable models offered in 2008. 

Meanwhile, gasoline-only vehicles exhibited an improvement of just 2.6 mpg. 

However, that rate of improvement will likely change over coming months as  automakers introduce more small capacity, turbocharged four-cylinder engines into everything from subcompacts to full-size cars.

2012 Toyota Prius V station wagon, Half Moon Bay, CA, May 2011

2012 Toyota Prius V station wagon, Half Moon Bay, CA, May 2011

Wagons, Not Compacts, Improved The Most

While most small cars are more efficient than larger ones, the largest amount of improvement in gas mileage from 2008 to 2012 didn’t come from sub compact or compact cars. 

In fact, station wagons demonstrated the greatest fuel improvement over the period, with average gas mileage rising from 21.9 mpg to 26 mpg.

While that might not sound impressive, it’s important to remember that a 4.1 mpg gas mileage improvement in a vehicle that gets a low 20 mpg economy is a much larger change than a 4.1 mpg gas mileage improvement in a vehicle that gets 40 mpg or higher. 

A Long Way To Go

It’s good to see gas mileage rising fleet-wide, but with only a 3 mpg improvement over the past 4 years, automakers have a long way to go in order to hit the 2016 CAFE and 2025 CAFE requirements. 

In fact, in order to reach the 2016 CAFE standard of 36 mpg, automakers will have to more than quadruple the past 4 years’ gas mileage gains in the coming 4 years.

That’s a tough target to meet, but with more implementation of mild hybrid and full hybrid drivetrains, turbocharged, small-capacity engines and an increase in plug-in vehicles, it might just be possible. 


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