Transportation Secretary Mary Peters announced an acceleration in the CAFE standards this afternoon. I think a gasoline tax is superior to the CAFE standards as a policy mechanism to reduce CO2 emissions. From the Vox Baby classic, "Don't Linger in this CAFE:"
The first issue, as I've alluded to earlier, is that the problem we care about is total usage of gasoline. Total use is the amount of miles driven divided by fuel economy. CAFE standards, at best, address fuel economy, but they provide no incentive to economize on the number of miles driven. This is why a gas tax is better--it allows people to decide how they want to conserve on fuel usage, fewer miles or fewer gallons per mile.
The second issue is that the CAFE standards operate at the level of a fleet of vehicles produced by one manufacturer. I have never heard of a rationale for regulating a company's whole product line. The more economy cars a company makes, the more fuel-inefficient cars it can make without penalty. Why provide an incentive for Toyota to make larger cars just because it happens to make good small cars? If the objective is to regulate the average fuel economy of all cars on the road, then there ought to be a tradable permit system established. We would get a better variety of cars on the market, though not at any one particular dealer. Pure welfare gain.
The third issue is that the CAFE standards operate in a hidden fashion, and as a result there have been plenty of abuses. CAFE standards are negotiated behind the scenes with a few entities (the manufacturers). They lobby for complexity and then exploit loopholes, like the different standards for cars and light trucks or, as I fear, all these new flavors of SUV. Lack of transparency is the enabler of bad policy. Is there anything more transparent than a gas tax at the pump?
Keep it simple. Scrap CAFE, set a higher gas tax, and return the aggregate revenues from that gas tax through lower income taxes in a progressive fashion.
We can do better. All it takes is leadership.