Consumers are enjoying the lowest retail gasoline prices in years, a welcome ray of light in an ever-darkening economic picture.

That's good news for financially strapped American families and for the domestic auto industry, which has struggled to produce the high-mileage vehicles consumers wanted when gas prices spiked at more than $4 a gallon over the summer.

But in the long run — as difficult as this is to accept — low gasoline prices hurt America more than they help. They encourage continued reliance on gas-powered vehicles and harm the efforts to lower carbon emissions that contribute to global warming. They discourage research into new, nonpolluting transportation energy sources — the single greatest technological challenge of the 21st century.

Consider what happened during the early 1980s, when gas prices soared to the then-unheard-of price of $1.38 a gallon. It triggered a surge of research into alternative energy sources such as solar power and electric vehicles. But as soon as prices began to drop, as they did in 1982, so did the rush of investment and research into alternative energy.

Adjusted for inflation, that previous average high gas price of $1.38 was the equivalent of $3.14 a gallon. We didn't see average retail prices that high again until this year.

But when gas prices and investment in alternative energy fell in this country in the 1980s, they didn't drop everywhere. In Europe and in Japan, high gasoline taxes kept fuel prices relatively high. That encouraged conservation and provided investors with greater confidence that the money they pumped into developing new technologies would earn an acceptable return.

The result was that Japanese car companies were the first to market new hybrid cars, and European companies led the way in producing new, cleaner diesel vehicles. American car companies, meanwhile, kept churning out large, gas-guzzling SUVs.

After years of failed attempts to increase mileage requirements for new cars — efforts steadfastly opposed by American auto manufacturers and their unions — Congress finally succeeded last year. As a result, U.S. cars must average 35 miles per gallon by 2020. European cars, in contrast, averaged 38 miles per gallon in 2006.

If increasing mileage standards has been difficult, hiking gas taxes has been unthinkable. Although the idea is floated occasionally (most incongruously by then-Rep. Dick Cheney in the 1980s, who supported a plan to tax imported oil), it never has received a serious airing. It should.

The nonpartisan Congressional Budget Office reported in 2004 that increasing the federal gasoline tax — which has been 18.4 cents a gallon since 1993 — would reduce consumption faster and at less cost than increasing mileage standards.

Obviously, it would not be painless. Consumers would be paying significantly higher prices, and the federal Energy Information Administration predicts that as the global recession abates, gasoline prices will resume their upward climb.

But the impact of higher gas prices could be offset somewhat by reducing other taxes or through a federal income tax rebate. In the meantime, it would reduce gas consumption significantly.

That would help undercut the financial strength of such countries as Iran and Russia that, armed with a surplus of petrodollars, have been unfriendly to American interests. And combined with other tax incentives, it would encourage U.S. investment in energy alternatives.

The nation that succeeds in developing and deploying new, green technologies will have a major economic advantage in the decades to come. It's crucial that the United States be that nation.

Congress should raise the federal gas tax and push America toward innovation and energy independence.