Cars Have Gotten Better In Everything Except Fuel Economy

This is why when I hear "Best fuel economy in its class" - and the commercial is referring to 20mpg - and my 10yr old car gets the same - I'm pretty discouraged about our long term prospects.

Yglesias:

From 1980 to 2004 the fuel economy of U.S. vehicles has remained stagnant despite apparent technological advances. The average fuel economy of the U.S. new passenger automobile fleet increased by less than 6.5 percent, while the average horsepower of new passenger cars increased by 80 percent, and their average curb weight increased by 12 percent. For light duty trucks, average horsepower has increased by 99 percent and average weight increased by 26 percent over this period. But there’s more to this story: in 1980, light truck sales were roughly 20 percent of total passenger vehicles sales — in 2004, they were over 51 percent.\

In Automobiles on Steroids: Product Attribute Trade-Offs and Technological Progress in the Automobile Sector (NBER Working Paper No. 15162), Christopher Knittel analyzes the technological progress that has occurred since 1980 and the trade-offs that manufacturers and consumers face when choosing between fuel economy, weight, and engine power characteristics. His results suggest that if weight, horsepower, and torque were held at their 1980 levels, fuel economy for both passenger cars and light trucks could have increased by nearly 50 percent from 1980 to 2006. Instead, fuel economy actually increased by only 15 percent.