HOW CAN VIRGINIA'S counties keep development from overwhelming their roads and other public services? The question looms larger after the Virginia Supreme Court's decision that counties -- in this case Prince William -- may not make residential developers pay for the road improvements their projects make necessary.

The decision, on top of other state court rulings, leaves Virginia's fast-growing counties in a fix. In many other states, local governments can levy new taxes for highway improvements, delay development or coordinate it with road work, or required the developer and home buyers to bear the added costs. But not in Virginia. The state's laws and courts have left counties with little power to slow development, even for good cause. Now can counties build their own primary and secondary roads. Those are provided by the state -- and state funds have been inadequate for years. That is why Northern Virginia counties have tried, with some success until now, to get developers to assume some road-improvement costs.

Now the court has said the counties must wait on the state. There is an irony in this. The commonwealth took over road-building about 50 years ago to accelerate it -- "get Virginia out of the mud" -- and free local governments from heavy burdens of debt. The program, financed by the gasoline tax and other user charges, was a prime example of "pay-as-you-go." For a time, it worked. But recently the highway fund's growth has lagged. Meanwhile, suburban needs for mass transit have put new financial pressure on state and local governments alike.

To keep growing counties out of the mud, so to speak, the General Assembly should overhaul the whole system of highwayt financing. Shifting to a percentage-of-price gasoline tax would be at least increase revenues as prices go up. The allocatiof road money within the state needs to be reviewed, however prickly that may be. Finally, the counties should be granted more authority to manage growth and tax themselves for services the state fails to provide.