As with many other policies in his State of the Union address, President Bush’s call for improved fuel economy standards was short on details. Fortunately, lawmakers will soon consider legislation, including a bill to raise the standards to 35 miles per gallon. This approach, which is supported by Maine’s senators, will reduce oil consumption and greenhouse gas emissions more quickly and consistently than the president’s proposal.

In his address last week, the president made much of diversifying and stretching the country’s energy supply. In addition to greater use of alternative fuels to power automobiles, President Bush advocated reforming and modernizing the country’s fuel economy standards for cars to conserve up to 8.5 billion gallons of gasoline by 2017.

Reform and modernize is not the same as increasing. The president said he wanted to change the standards, known as Corporate Average Fuel Economy, or CAFE, as his administration previously did for light trucks. Rather than raise the standard for all light trucks, the administration created a new matrix that divides light trucks, a category which includes minivans, SUVs and some vehicles, such as the Subaru Outback and PT Cruiser that most people think of as cars, into six categories. The larger the truck, the less demanding the fuel economy requirements. The largest SUVs, such as the Hummer, are exempted from the rules entirely.

The new rule, announced in 2005, referred specifically to difficulties faced by “full-line manufacturers who have large sales volumes at the larger and heavier end of the light-truck fleet,” a reference to American automakers such as General Motors and Ford which continue to make the largest SUVs and trucks. Despite such concerns, the National Academy of Sciences found that minivans could get more than 36 miles a gallon and light trucks 32 miles a gallon using existing technology.

American car companies are now saying that raising the CAFE standards for cars is an outmoded means to deal with oil consumption and climate change. They are instead calling for more government support for alternative energy sources, such as ethanol and lithium-ion batteries.

No matter what the fuel source, vehicles should still be made to go further per gallon or charge. Biofuels, such as ethanol, have a lower energy density than gasoline so without efficiency improvements in automobile engines, vast amounts of corn, switch grass or other fuel would be needed to reduce the country’s reliance on oil.

That’s why higher CAFE standards, like those in legislation sponsored by Sens. Olympia Snowe and Susan Collins, along with 10 other senators, are still needed. Their bill would raise the standards for all vehicles to 35 miles per gallon by 2019. They now average 25 miles per gallon. The legislation would reduce vehicular greenhouse gas emissions by 18 percent while saving about 2.1 million barrels of oil per day by 2025, roughly the same amount the United States now imports from the Middle East. The oil savings are four times greater than under the president’s proposal.

The president is right to, as he did in his State of the Union address, support more production of alternative fuels. This policy goes hand-in-hand with higher fuel economy standards.