Fuel economy shifts little in 2 decades — study

Source: Andrea Simmons, Atlanta Journal-Constitution, • Posted: Thursday, August 20, 2015

In the last two decades, the average fuel economy of American vehicles has improved less than 1 mpg, according to new research.

The U.S. government has been tracking fuel economy since 1923, when all vehicles on the road got an average of 14 mpg. As car size ballooned and gas got cheaper, that average declined to 11.9 mpg by 1973, before the country’s energy crisis drove a rapid rise to 16.9 mpg by 1991.

Between 1991 and 2013, however, the average fuel economy of all American vehicles rose 0.7 mpg, to 17.6.

While this era saw the rise of the gas-chugging SUV, the recent popularity of more fuel efficient cars has yet to make an impact on the average, the researchers found.

“One fundamental problem with improving the fuel economy of the entire on-road fleet is that improvements in fuel economy of new vehicles take a long time to substantially influence the fuel economy of the entire fleet,” the report said. “This is the case because it takes many years to turn over the fleet.”

The average age of American vehicles on the road hit a record high of 11.5 years old this year, as drivers held on to their cars during the recession.