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.

Other industrialized democracies have accepted much higher gas taxes as a price for roads and bridges and now depend on the revenue. In fact, Germany’s gas tax is 18 times higher than the United States’ (and seven times more if the average state gas tax is included). The federal gasoline tax contributed about $25 billion in revenues in 2009.

Raising the tax has generally succeeded only when it was sold as a way to lower the deficit or improve infrastructure or both. A 1-cent federal gasoline tax was created in 1932, during the Depression. In 1983, President Ronald Reagan raised the tax to 9 cents from 4 cents, calling it a “user fee” to finance transportation improvements. The tax rose again, to 14.1 cents in 1990, and to 18.4 cents in 1993, as part of deficit-reduction deals under President George Bush and President Bill Clinton.