GIVEN THE stormy history of efforts to provide public transportation for the physically handicapped, Metro's latest proposal to equip half its buses with special lifts isn't likely to generate great cheers in many places. But precisely because of that history, it deserves support.

The costs of the proposal are higher than many taxpayers will like, and the service to be provided falls short of what lobbies for the handicapped have sought. But the plan encompasses a reasonable and responsible effort to provide improved bus service for the disabled.

Many organizations of the handicapped have insisted that Metro equip all buses with lifts. That's talking huge dollars: a study for Metro says it would run $10 million a year for an uncertain period -- give or take inflation, costs of equipped buses, replacement schedules for new buses, maintenance and other additional costs -- to buy only buses equipped with lifts.

The half-and-half purchase proposal would cost $5 million and would put lifts on 50 percent of the fleet by the mid-1990s. That's a substantial change. Right now Metro has 225 buses with lifts, or 14 percent of its fleet. But many of the lifts and their buses have broken down for a variety of reasons. About 52 of the buses with lifts are used on daily routes, and an average of 56 in Metro's "On Call" service, which allows riders to call a day in advance for service on other routes.

Metro's immediate plans call for buying about 100 new buses with lifts. Though the U.S. Department of Transportation has not issued final rules, Metro officials say the 50 percent plan appears likely to comply with current federal proposals. In calculating a reasonable formula, officials had to consider the likely use of this new equipment -- and therein lies justification for a measured approach.

The study estimates that there are about 47,200 "ambulatory disabled" residents 16 and older who live in Metro's service area. Of this total, 2,288 are said to use wheelchairs; 13,319 use canes, walkers and other devices; and the rest do not use such aids. And only a portion of these disable residents are considered likely to take buses, because they have difficulty getting to bus stops and may encounter other impediments. But if half the buses could transport these disabled people, who knows how many more might discover new mobility? And who more than the handicapped should be able to look to mass transportation for that mobility?