MIT Study: Vehicle Weight Gains Have Offset Potential MPG Improvements
Although it’s true automakers have improved average miles delivered per gallon to meet government fuel economy mandates here and around the world, between 1980 and 2006, efficiency for U.S. market vehicles increased only around 15 percent.
Not so great you say? Perhaps, but while those gains might seem modest, according to a research paper by MIT economist Christopher Knittel, they don’t account for the fact that vehicle offerings – not unlike fast food restaurant menus – have been tending toward a preference to supersize. That is, during this same 26-year period, vehicle curb weights increased by 26 percent, while engine power output grew by a whopping 107 percent.
The paper, titled, “Automobiles on Steroids,” said that given technological advancements we’ve seen in automobiles in the last three decades, if Americans today were driving cars that were equivalent in size and power to those on the road back in 1980, the fleet fuel economy average would be approximately 37 mpg – 10 mpg above the current average of 27 mpg.
“Most of the technological progress [we’ve seen] has gone into compensating for [weight and horsepower],” said Knittel, who observed that despite gains garnered from introduction of features such as electronic fuel injection, multi-cam engines and transmissions with an ever increasing number of speeds, Americans in particular continue to favor, larger, more powerful and better equipped vehicles. Further, the situation is not helped by the fact that in real terms, U.S. gas prices today are on average, some 30 percent lower than they were in 1980.
“I find little fault with the auto manufacturers, because there has been no incentive to put technologies into overall fuel economy. Firms are going to give consumers what they want and if gas prices are low, consumers are going to want big, fast cars.”
Although the Obama administration has committed to increasing Corporate Average Fuel Economy (CAFE) requirements from 35.5 mpg in 2016 to 54.5 mpg (about 40 mpg on the window sticker) in 2025, Knittel believes this won’t be enough by itself to significantly boost fuel economy and reduce fossil fuel dependence. He, like many environmental policy analysts, said he believes that in the long run, a fuel surcharge would be more effective.
Mileage regulations like CAFE “end up reducing the cost of driving,” he said. If you force people to buy more fuel-efficient cars through CAFE standards, you get what’s called “rebound (a concept where people actually end up driving more and consumption increases).” On the other hand, he said a fuel surcharge would, in his view, spur demand for more fuel-efficient vehicles without resulting in such a rebound scenario.