Improvements in the fuel economy of cars is being hindered by the increasing weight and power of cars according to new research by the Massachusetts Institute of Technology (MIT).
Contrary to common perception, automakers have actually made huge leaps in the fuel efficiency of cars in recent decades through advancements in technology, the Institute reports. But sadly these improvements have hardly translated into increased the miles to the gallon of cars on the road, thanks to bulging waistlines and more horsepower.
Studying all the cars sold in the US over the last three decades, the Institute found that average fuel economy improved just over 15 per cent-a relatively modest improvement. But, while focusing on cars sold in the States between 1980 and 2006, the report also found that the average curb weight of those vehicles increased 26 per cent, while their horsepower rose 107 per cent. All factors being equal, fuel economy actually more than doubled (60 per cent) during that time, as MIT economist Christopher Knittel reaffirms in the new research paper, “Automobiles on Steroids,” just published in the American Economic Review.
Thus if Americans today were driving cars of the same size and power that were typical in 1980, the country’s fleet of autos would have jumped from an average of about 23 miles per gallon (mpg) to roughly 37 mpg, well above the current average of around 27 mpg.
Instead, Knittel says: “Most of that technological progress has gone into [compensating for] weight and horsepower.”
While the US is well known for its love of large, heavy vehicles, even here in Europe, cars have historically got heavy since the 1980s. Back in the States, Knittel reports that a major reason why fleet-wide mileage has only slowly increased is that so many Americans have chosen to buy bigger, less fuel-efficient vehicles. In 1980, light trucks represented about 20 per cent of passenger vehicles sold in the United States. By 2004, light trucks — including SUVs — accounted for 51 per cent of passenger-vehicle sales. Furthermore, gas prices dropped 30 per cent between 1980 and 2004, when adjusted for inflation.
However no gas prices are rising and as consumers and governments look for improvements in economy, Knittel calculates that car makers could meet the new CAFE fuel economy standards by simply maintaining the rate of technological innovation experienced since 1980 while reducing the weight and horsepower of the average vehicle sold by 25 per cent.
