A new Maryland Department of Transportation study is looking at the possibility of extending the Washington Metrorail system to Bowie. Unfortunately, to reach the intersection of Routes 50 and 301, the liveliest proposal calls for extending the Blue Line along Central Avenue from the Addison Road station.

It would make a lot more sense to extend the Orange Line from New Carrollton along the Route 50 right-of-way to the same terminus. It would be a shorter route, cheaper to build, and it would cause much less disruption of existing residential areas. Parking lots would be easier to locate, could be larger and would be tempting for commuters using Route 50.

Let's not make the same mistake that was made in Washington. The convoluted routes taken by the various subway lines in the District were carefully planned to pick up the greatest number of people along the way. The idea was to run the subway lines as close as possible to existing centers of population so that people would have ready access to the subway for transportation to and from work. Great planning, right? Wrong!

Look at what's happened in the District in the 14 years since the subway opened. The layout of the city near the subway lines has changed drastically. Residential units, especially those located near outlying stations, are being sold, razed and replaced by high-rise commercial buildings. In a short while few of the people the subway was designed to serve will still be there.

It seems it would have been wiser to lay out the subway along major commercial routes of the city, following the original L'Enfant plan. This design would have reduced dislocation, allowed straight line construction at significantly lower cost and provided more efficient service.

If we build along Route 50, our costs would be lower, we wouldn't lose housing we can't afford to lose, we wouldn't bring unwanted development to residential areas, we'd provide easy access to the stations via a superhighway and its feeders, and we'd have more efficient and speedier service in the long haul.

TOM KEEGAN Bowie