Audrey Moore -- originator of the "Just say no" school of municipal management -- is now responsible for everything that happens in Fairfax County, including its clogged roadways. Unfortunately, during her first weeks as the new chairman of the Board of Supervisors, she is showing signs of falling into the familiar "we-need-more-roads" trap. Moore must say no one more time.

It takes nearly a decade and millions of dollars to plan and build a new road. Yet years ago, economist Anthony Downs concocted the Theory of Peak-Hour Congestion, a convincing argument that more roads will not end traffic jams. His theory predicts that each new lane added to a roadway only results in a new level of peak-hour congestion. In other words, the traffic jams only get bigger.

Once motorists seeking relief from a congested road learn of a new, more passable roadway, they alter their home-to-work route and begin using it. But soon the more free-flowing road is as bogged down as all others in the network, and a new equilibrium sets in. With each new or widened road the cycle is repeated as an ever-growing number of additional motorists seek out, and clog, uncongested roads.

Downs is not alone. Last fall the Fairfax County Goals Advisory Commission also concluded that new roads are not the whole answer. The commission said, "There has been insufficient emphasis on improving use of our current . . . transportation network by means of alternatives such as HOV, flextime, van pools, fringe parking, bus service, et cetera."

That open-ended "et cetera" caught my eye. With Moore (former board chairman Jack Herrity calls her "Mrs. No") in the driver's seat, the county is now ready for the most powerful of all tools available to a municipality for controlling the use of a scarce public commodity. I am referring, of course, to rationing.

Rationing has already been used in Fairfax, land of plenty. How did our county leaders react last summer when insufficient rain fell to keep water-supply basins at adequate levels? Did they rush out and buy water on the open market? No, sir. They simply restricted the use of -- that is, artificially lowered the demand for -- the scarce public commodity. Houses with odd street numbers were allowed to draw heavily on the water supply -- for filling back-yard pools and washing BMWs -- only on odd-numbered days; even-numbered houses were allowed the privilege on even-numbered days.

Since road networks and water-supply networks are both public utilities, I say let's begin treating them alike. Why should we allow the use of a proven and effective public management tool in one instance and deny its use in another? From 6 a.m. to 9 a.m. and from 4 p.m. to 7 p.m. weekdays, space on county roads is scarce. In fact, during those hours there is probably no public commodity in greater demand or more limited supply.

Fortunately, a workable rationing plan is ready for immediate implementation. All motor vehicles have license tags, and it is these tags that could control drivers' access to the public roads. Instead of house numbers, the ending license plate number or letter could determine which cars could operate on public roads on any day of the month.

Best of all, in an affluent county like ours where almost every household has more than one vehicle, the only hurdle to overcome is relief to those unfortunates holding auto tags all ending in odd or even characters. Households with only one auto would receive a special hardship plate allowing their lone vehicle access to the roads on any day.

I'm sure the county's transportation planners can easily handle the details of implementing such a plan after consulting their peers in the water department.

By effectively reducing the number of cars trying to travel on our limited roadways, traffic jams would be eliminated, millions of dollars otherwise wasted on new roads would be saved, and Audrey Moore would have kept her campaign promise to solve this seemingly insoluble problem.

Ronald Fraser lives in Burke.