The worst conclusion Congress could draw from a new study on vehicle fuel efficiency is that because members of the National Academy of Science believe previous fuel advances led to more highway deaths nothing can be done now. The NAS report, instead, should spur legislation that uses its half dozen suggestions to safely increase efficiency and reduce air pollution.

The NAS panel found that, since the beginning of rules requiring corporate average fuel economy in 1975 until about 1985, cars became more fuel efficient through engine improvements, aerodynamics and weight reduction. Since ’85, technological advances have focused on making vehicles faster and more powerful. Further fuel efficiency is possible, particularly in the largest vehicles such as SUVs and light trucks, and, over time, technologies currently offered in the European and Japanese markets could help here, it reported. But an even better way to encourage greater efficiency, it said, are tradable credits for fuel economy improvements, cash incentives for the purchase of economical vehicles and cash penalties for gas hogs and higher fuel taxes, among others.

What has drawn the most attention in the study, however, is its conclusion – disputed by two members of the 13-member group – that rapid increases in the early years of the CAFE standards forced car manufacturers to meet rules by reducing the weight of their vehicles, probably resulting by 1993 in between 1,300 and 2,600 traffic fatalities. It is a shocking possibility and one on which Congress should urge further study. But the panel also concluded that there is not necessarily a trade-off between fuel economy and safety, and that intelligent choices and sufficient time for making changes could allow manufacturers to maintain safety while using gas more efficiently, although it left the choices of how to proceed up to Congress.

Fortunately, Congress already has bills to improve CAFE standards pending that could achieve the twin goals of reducing air pollution and the dependence on foreign sources of oil. But it could improve the legislation by adding some of work of the NAS panel. For instance, Congress could raise the gas tax and use the proceeds to reward buyers of fuel-efficient vehicles within each vehicle classification. So, for instance, a driver who needs a pick-up truck would be rewarded for choosing one that was efficient compared with other pickups.

Two other recommendations from NAS should also be adopted. Currently automakers have fuel-economy fleet rules for both foreign and domestic sales, originally included to keep jobs from going overseas. The panel could find no evidence that the rule had any effect on jobs and recommends eliminating it. Second and more difficult, manufacturers get credit for making cars with that can run on both gasoline and gasohol, but since relatively few drivers use anything but gasoline, the credit is largely wasted and should be phased out.

The NAS report gives all sides in the debate over fuel efficiency plenty of room to agree. As important, it shows that Congress has no excuse for not acting on this means for cutting greenhouse gases and making the nation less reliant on OPEC.