WE'RE BARELY into May, but Metro General Manager Richard S. Page thinks it's none too soon to warn everyone that come July, all the buses and subways may grind to an unscheduled halt. If so, the failure won't be mechanical, but human. That is when a wildcat strike over cost-of-living payments could erupt. Mr. Page would love to be totally wrong about this, of course, but he is right to address the possibility openly and now, so people can understand what is at stake.

Riders should know, too, that July will mean two other changes at Metro -- one of them welcome and the other confusing. There will be more money raised for the transit system through a 2 percent gasoline tax in Northern Virginia that goes into effect on July 1; and as of June 29, a brand new set of bus and subway fares -- destined to be even more complicated than those logarithmic monstrosities currently foisted on riders -- will be cranked into whatever is left of a moving transit system.

The effects of any of these possible summer occurrences, ranging from annoyance to total disruption, may depend in no small way on how much public reaction there is to them now. For example, Mr. Page and Metro board members, who also are elected officials from around the region, could use taxpayer support in their effort to curtail what has become quite an expensive cost-of-living clause in the contract that now covers 4,800 drivers, mechanics and other employees. They receive quarterly increases equal to the rise in the Consumer Price Index. This meant that the last payment was at an 18 percent annual rate. The board has voted to limit future increases to 6 percent for the year.

Unresolved contract issues go to binding arbitration, but if procedures drag on beyond July 1, Metro will not make a July payment under the current arrangement -- which could set off illegal job actions similar to the eight-day stoppage that took place two summers ago. At this point, two things should be clear: 1) that some lid on the cost-of-living payments is in order, or else service -- and jobs -- will have to be cut; and 2) any employees who stage a strike of their own, in defiance of their union and collective bargaining procedures, should be dealt with severely.

As for those new fares, Metro board members could stand some sobering thoughts from any riders who oppose any more complications, such as the contemplated shift from three different flash passes to -- look out -- five. Though Mr. Page is an advocate of simpler fares, so far the board has ignored his advice and fallen instead for convoluted policies that cater to provincial interests instead of to a rational regional fare schedule. Not only are the complicated fares harder to explain and more difficult to administer, but they can be costly as well. If public support -- and use -- of the system is still an objective, Metro should make its fares as simple as possible.