I'm a daily MR reader, so I like them, but this is classic Libertarian exercise in manipulative framing. Gasoline consumption does, in fact, increase non-linearly with speed at highway speeds. Police departments do have to pay their officers salaries. He could just as easily have written it this way: - the real cost of gasoline is about $10/G. when you count pollution, military expenditures to protect supply, etc. - Big Government and lying politicians bring that down to $4 to curry favor with voters - that means voters drive bigger cars faster than they otherwise would - that leads to an ethos of unlimited speed - all of the above leads to highway casualties - drivers who try to drive responsibly risk being run over by maniacs driving 4K lb behemoths at 80 mph.

Note that the above does not represent my views, but it fits the evidence as well as Tabarrok's take.