Eric Marnell {"The Dulles Toll Road Quagmire," letters, Nov. 11} apparently fails to see the futility of further widening of radial highways into Washington. The Dulles Commuter Road was jammed before the traffic signs were installed. Traffic jams appeared in Reston. Tysons Corner is as bad as ever. An almost instantaneous burst of sprawling development took place cheered on by ads touting the new road.

It is understandable that a Dulles Road commuter would come to the simple conclusion that opening the coveted airport lanes would solve the problem, but there is adequate local evidence showing that this is not true. Shirley Highway and I-270 are prime examples: when new lanes are built, they are soon filled to capacity by the rampant development they encourage. At least the I-270 commuters have a choice of parallel Metro and MARC rail services; they just came too late.

It may take another fuel crisis to make us realize that the high-speed rail line, for which space has been reserved, should be the next step in solving the Dulles and Rte. 7 "quagmire." Every shot fired in the Persian Gulf gets us closer to the crisis. Using a high-capacity system, independent of petroleum use and traffic, combined with coordinated residential and commercial development will help ensure quality life in the region well into the 21st century. JAMES R. CHURCHILL Alexandria