IN UNCOMMONLY short order, both neighboring state legislatures are coming to grips with important matters--including the politically unpleasant business of talking taxes and what to do about transportation. In Annapolis, a special joint General Assembly committee has already agreed on a tax bill that would add to the price of gasoline and pay for highway and bridge repairs. And in Richmond, a number of tax proposals and resolutions are under consideration that, in addition to financing roads, might keep the Metro subway system in business as well as in compliance with federal stipulations.

As legislative purists will be quick to note, neither general assembly is likely to enact the perfect bill to meet its state's critical transportation needs. But there is progressive movement on both fronts--and early enough for some constructive results.

The Maryland measure agreed to so far, for example, is not everything Gov. Harry Hughes has been seeking. If enacted, the committee proposal would reduce by more than half the 4.4 cents that Mr. Hughes wants to add to the state's current 9-cents-a-gallon tax. This would mean that the governor would have to curtail many of the transportation projects he has included in his proposed budget; but the new proposal would tie the gasoline tax to the price of fuel, as a percentage, which makes sense. There is time, too, for the lawmakers to reach at least some understanding about when and how mass transit construction might be included in the revenue distributions.

The Virginia roads-and-rails maneuvers include an effort to meet the federal government's insistence on assurances from each participating members of the Metro system of a "stable and reliable" source of revenue for operating costs in the future. Ideally, the legislature would guarantee some share of tax revenues for Metro; but nobody sees that happening, and the focus now is on some sort of legislative resolution taking note of what has been done to finance Metro and what cooperation can be expected between the state and local governments in Virginia to commit local monies for operating costs. That is a reasonable effort that the U.S. Department of Transportation could-- and should--accept for now.

The critical common denominator in either legislature is accommodation. The more rural highway interests and the areas that look to mass transit should recognize practical as well as political trade-offs: mass transit service in one area may reduce the needs for more roads, for example. There will be some jockeying and jostling for shares of any transportation money, of course; but for now, the negotiations in both capitals have been on the high road, and that is encouraging.