CALL IT "revenue enhancement" or simply a user fee, but Transportation Secretary Drew Lewis wants to go to the gas pumps for more federal transportation money--and that's the right place for the administration and Congress to be heading. Through an increase in the gasoline tax and/or other fees such as excise taxes on tires, Mr. Lewis would direct sorely needed revenues not only to highway projects both old and under way, but to the building and rebuilding of subway systems and the replacement of bus fleets. While this proposal may be too sensible to sit well with competing highway and transit interests, the smart money should go for it as a mutually beneficial package.

Under discussion is an increase in the federal at- the-pump tax--from 4 cents to 9 cents per gallon-- that could add about $5 billion annually to the available federal funds for transportation. About $4 billion would be devoted to highway projects, including completing the interstate highway system and maintaining those highways already built and already in various serious stages of disrepair. The other $1 billion would be used to start a special account for mass transit projects, with emphasis on rebuilding some of this country's sorrier-looking subways-- New York's, to cite one hideous example--and continuing new rail systems--Washington's, to cite one random, cherished example.

There is one important modification that should be made in this logical proposal: instead of establishing a 5-cent or money-amount increase, the gasoline tax should be set at a percentage of the gallon price. Otherwise the relative amount diminishes with inflation--which is what has left federal and state transportation high and dry as construction costs have risen.

In the more affluent past, highway and mass transit interests preferred to go their separate, competitive ways in search of federal money, but as staff writer Douglas B. Feaver noted yesterday on The Federal Report page, a growing number of state transportation directors are realizing that good transit systems can ease car travel on the highways, and contractors are as content to build tunnels as they are highways.

Ideally, Congress should do away with the whole concept of a special trust fund with earmarked money and should finance transportation projects out of general revenues. But, instead of holding his breath until that happens, Secretary Lewis has come up with a practical and immediate solution that deserves executive and congressional consent if this country is at all serious about transportation.