A plan to take stock of O'ahu roadway conditions in a scientific way is a needed step toward a city maintenance schedule steered logically, rather than by the politics of the "squeaky wheel."

There's a fairly hefty payout required to follow this new, more scientific route. Officials from the Department of Facilities Management showed the City Council the $500,000 contract for an inventory covering every city street and roadway on the island — nearly 1,500 miles of them.

But the payment is worthwhile if it helps the city avoid deepening the maintenance rut we've dug by allowing a general deterioration of the roads. It's a condition that developed because of a tendency to base repair priorities on visual spot checks.

Too often, the decision on which road gets fixed first is made depending on who makes the complaint — and how loudly they make it.

Instead, facilities officials want to create a "roughness index" by using special equipment that records the bumps, large and small, a vehicle encounters as it passes over the surface. Amplified by video images recorded at the same time, the data base would make it clear which roads need attention soonest.

Leaving surface flaws unrepaired for too long can lead to subsurface structural damage that becomes a more chronic, expensive maintenance chore. Having a repair road map like this can help make the most of limited funds, in the same way the state schools direct maintenance spending according to a repair matrix.

The real challenge is for the City Council, which will have to set aside district politics and instead make sure the index is directing the work when the next budget review comes up. But — once you peer beneath the surface — this roadway inventory seems to be a useful investment of repair dollars.