"This paper estimates the technological progress that has occurred since 1980 and the trade-o ffs that manufacturers and consumers face when choosing between fuel economy, weight and engine power characteristics. The 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; this is in stark contrast to the 15 percent by which fuel economy actually increased."
Via Treehugger.
