HAVING SPENT THE better part of its organizational life finding ways to discourage car traffic in the city and to put more people on mass transit, the D.C. Department of Transportation has now come up with a policy that not only flies in the face of that effort but also takes it all out on the school children in the city. By departmental edict -- without even waiting for consideration of legislation pending before the council -- students will no longer be able to use discount bus tokens or train tickets on Metro for weekend, vacation or summertime extracurricular activities.

This misguided restriction, taken in the name of municipal austerity, is part of a department proposal to double the current 10-cents-a-ride fare to and from school to 20 cents. While no one enjoys the prospect of an increase in the fare, that isn't the big issue. The city does have reason to change the subsidy arrangement, since school fares have never been tied to increases in adult fares. Thus, each time adult fares have gone up, the city has had to pay Metro the differences between 10 cents and the new adult rate. So the mayor and the council do agree that a higher school fare is in order.

But why bar students from discount rides for worthwhile extracurricular and other non-classroom scholastic activities such as trips to the library or weekend and vacation activities at the schools? Why discourage students from participating in athletics, the D.C. Youth Orchestra or any of dozens of activities that do not meet the narrow qualifications set forth by the city? Should the students drive cars, or should their parents drive them?

Council member Hilda M. Mason (Statehood-At Large) thinks that's wrong, and she's right. Under a bill introduced by Mrs. Mason and three other council members, the school discount would always be one-third of the lowest regular adult fare -- but without the restrictions announced by the transportation department. This measure deserves passage -- and until its enactment, the city should leave the present arrangement as is.