David Sandalow argues that we ought to put a regulatory cap on allowable horsepower. He notes that 30 years go, the average car could go 0 to 60 in 14.1 seconds, now it's 9.6 seconds. Average horsepower in 1980 was 100, today it's 220. And of course we don't actually get around faster because the limiting factor in real world speeds is traffic congestion and safety rather than engine size. Regulation, he plausibly argues, could get us out of a horsepower arms race in a way that would have little negative impact on anyone's life while allowing us to capture technological gains in engine efficiency in terms of reduced fuel consumption rather than in terms of faster cars that let you get to the traffic jam more quickly.