It’s no secret that today’s vehicles are far heavier than those produced just a couple of decades ago – largely due to increased safety regulations and luxuries like heated seats and power windows – but a new report reveals just how detrimental those weight gains have been to improved fuel economy.
A number of technological advances have resulted in increased fuel economy over the years, but a new study by MIT economist Christopher Knittel discovered that the average fuel economy of vehicles sold in the United States between 1980 and 2006 only saw a 15 percent improvement in efficiency. The reason for those rather modest gains? During the same time period vehicle weight has increased 26 percent while horsepower is up an astonishing 107 percent.
According to Knittel’s work, fuel economy has actually increased by 60 percent between 1980 and 2006, but has been masked by heavier cars with more horsepower. Knittel estimates that if vehicles had maintained the typical weight and power of a 1980 model year car, the nation’s fleet economy would currently stand at 37mpg, rather that its actual average of 27mpg.
“Most of that technological progress has gone into [compensating for] weight and horsepower,” Knittel said.
Knittel found “little fault with the auto manufacturers” for the nation’s modest fuel economy gains “because there has been no incentive to put technologies into overall fuel economy.” Knittel insists that the only way to truly push the proliferation of fuel efficient automobiles is to raise the nation’s gas tax.
“When it comes to climate change, leaving the market alone isn’t going to lead to the efficient outcome,” Knittel said. “The right starting point is a gas tax.”
New CAFE regulations will require a fleet average of 54.4mpg by 2025, but Knittel notes that a shift back to 1980 power and weight standards in tandem with modern engine technologies would net a fleet-wide average of 52mpg by 2020.
