Raising Gas Taxes Beats Boosting CAFE Standards

Here’s a good laugh line if you find yourself in a policy meeting about how to reduce gasoline use: suggest increasing the gasoline tax. During my time in the White House, I attended several meetings on this topic, and inevitably someone (sometimes me) would offer that simple idea. Everyone would then chuckle at its political insanity, and the conversation would turn to Washington’s policy of choice, increasing fuel efficiency standards for autos and cars.

Those standards certainly can reduce future gasoline usage. But they are an incredibly inefficient way to do so. For some new evidence of just how inefficient, let’s turn the microphone over to the aptly-named Valerie Karplus, an MIT researcher, writing in the New York Times:

Politicians of both parties understandably fear that raising the gas tax would enrage voters. It certainly wouldn’t make lives easier for struggling families. But the gasoline tax is a tool of energy and transportation policy, not social policy, like the minimum wage.

Instead of penalizing gasoline use, however, the Obama administration chose a familiar and politically easier path: raising fuel-efficiency standards for cars and light trucks. The White House said last year that the gas savings would be comparable to lowering the price of gasoline by $1 a gallon by 2025. But it will have no effect on the 230 million passenger vehicles now on the road.

Greater efficiency packs less of a psychological punch because consumers pay more only when they buy a new car. In contrast, motorists are reminded regularly of the price at the pump. But the new fuel-efficiency standards are far less efficient than raising gasoline prices.

In a paper published online this week in the journal Energy Economics, I and other scientists at the Massachusetts Institute of Technology estimate that the new standards will cost the economy on the whole — for the same reduction in gas use — at least six times more than a federal gas tax of roughly 45 cents per dollar of gasoline. That is because a gas tax provides immediate, direct incentives for drivers to reduce gasoline use, while the efficiency standards must squeeze the reduction out of new vehicles only. The new standards also encourage more driving, not less. (Emphasis added.)

A gas tax wouldn’t be a win-win all around, of course. People would pay more in taxes immediately. So you might well want to pair the tax with other policies (e.g., offsetting tax reductions) to ameliorate that hit. (The same concern applies to carbon taxes.)

How Do Consumers Spend Engine Efficiency Advances? On Bigger, Faster Cars

Auto companies have made great strides in improving engine efficiency in recent decades. But those improvements haven’t done much to improve the fuel economy of America’s passenger car fleet. Instead, consumers have “spent” most of those efficiency improvements on bigger, faster cars.

MIT economist Christopher Knittel has carefully quantified these tradeoffs in a recent paper in the American Economic Review (pdf; earlier ungated version here). As noted by Peter Dizikes of MIT’s News Office: 

[B]etween 1980 and 2006, the average gas mileage of vehicles sold in the United States increased by slightly more than 15 percent — a relatively modest improvement. But during that time, Knittel has found, the average curb weight of those vehicles increased 26 percent, while their horsepower rose 107 percent. All factors being equal, fuel economy actually increased by 60 percent between 1980 and 2006, as Knittel shows in a new research paper, “Automobiles on Steroids,” just published in the American Economic Review.

Thus if Americans today were driving cars of the same size and power that were typical in 1980, the country’s fleet of autos would have jumped from an average of about 23 miles per gallon (mpg) to roughly 37 mpg, well above the current average of around 27 mpg. Instead, Knittel says, “Most of that technological progress has gone into [compensating for] weight and horsepower.”

This is a fine example of a very common phenomenon: consumers often “spend” technological improvements in ways that partially offset the direct effect of the improvement. If you make engines more efficient, consumers purchase heavier cars. If you increase fuel economy, consumers drive more. If you give hikers cell phones, they go to riskier places. If you make low-fat cookies, people eat more. And on and on. People really do respond to incentives.

What Should We Do With Higher Gas Tax Revenues?

Most of the economics bloggers I know favor higher gasoline taxes. Not immediately, of course, given our economic weakness. But eventually because of environmental and national security concerns.

As noted yesterday, Tim Kane of the Kauffman Foundation does a quarterly survey of economics bloggers. This time around, Tim included a question from me about the federal gas tax. Specifically, what would economics bloggers do with the money from a higher gasoline tax? (While allowing for the possibility that some don’t want it to go up.)

Here are their responses:

(Note: The federal gas tax is 18.4 cents per gallon; state gas taxes average another 30 cents, according to the American Petroleum Institute.)

As Tim notes in the full survey, “bloggers seem to love the gas tax.” Almost 85% of respondents supported a higher gasoline tax of which fully half would use the money for infrastructure spending. The remainder would use the money for deficit reduction or to reduce other taxes.