TODAY'S RELATIVE prosperity of state governments often blurs long-term financial vision--the ability to see huge spending needs that will linger long into the future. Transportation, for example: Maryland and Virginia are looking at staggering bills just to meet longstanding needs, including a new Wilson Bridge, transit improvements, road widenings and new highways. In Maryland alone, state experts are forecasting a $250 million deficit each year in transportation spending beginning in 2004.

If raising taxes is politically unappealing in flush times, elected leaders should come up with ways to set aside more funds. House Speaker Casper R. Taylor Jr. has such a proposal for the legislature come January. To augment Maryland's transportation trust fund, his plan would devote a portion of the state's sales tax to mass transit. In the first year, it would be one-tenth of 1 cent of the existing 5 percent sales tax. Each year for the next nine, an additional one-tenth of a cent would be earmarked. At one full cent, the yield would be about $500 million a year.

Money for highways and other transportation needs would continue to come from the gasoline tax and vehicle user fees that currently go into the trust fund. In explaining the separation of tax sources and uses, Mr. Taylor notes that about 80 percent of Maryland's sales tax revenues come from urban-suburban areas that also have the heaviest transit needs.

With one of the highest state gasoline taxes already, the speaker says, an increase in Maryland would be both a hard sell and insufficient.

But if any tax increase is out of the political question, dedication of a relatively small portion of sales taxes for transportation is an answer that the legislature should seriously consider.