When is $900 million not enough? Not this time

$1.5 billion a year — with another $2.1 billion to $5.4 billion a year needed to actually boost capacity.

Folks who ordinarily wouldn’t dare trumpet a cost estimate by a third party that stands to profit from more spending have, in this instance, latched onto it like the long-lost Gospel of Asphalt. That alone should give one pause.

If not, consider the ranges in play. Current maintenance spending is less than $500 million a year, including federal funds. Is the minimum needed for “maintenance” really triple that? Or even quadruple?

And the whole package really needs to be an increase of at least one and a half times today’s total DOT budget? Or as much as a 300 percent increase? All at once? Really? No, not really.

In fact, the Georgia DOT has publicly said, repeatedly, that maintenance — from resurfacing roads to mowing the grass alongside them — needs another $600 million a year. Privately, transportation experts concede the figure is closer to $400 million.

That leaves over a half-billion dollars per year to spend enhancing capacity. Over the next 20 years, that means as much as $12 billion more for construction.

That won’t build every project on the shelf. But it’s almost enough money, for example, to widen every stretch of interstate besides I-285 in Georgia (DOT cost estimate: $13.4 billion).

Alternatively, it’s almost enough to finish the Governor’s Road Improvement Program network that criss-crosses the state ($6.8 billion) ... to build out a managed-lanes network throughout metro Atlanta ($2.8 billion) ... rework the top end of I-285 ($3 billion) ... complete a dozen other “urban mobility” projects ($1.2 billion).

More likely, it means some combination of these projects and others. And there has never been more of a chance for the state to put money into mass transit projects, as some $300 million of the new money isn’t legally restricted to roads and bridges.

The bill also gives DOT much-needed flexibility in how it manages its various programs, mixing and matching federal and state money. Georgia is better positioned now to leverage investors’ dollars through public-private partnerships.

In fact, the biggest challenge going forward may be how to avoid driving up costs for labor and material. That’s a real possibility when an agency that normally spends a little over $2 billion a year suddenly has some $3 billion a year at its disposal. It would be a near-certainty if the increase were even larger.

No legislation is prefect. But don’t buy the idea that $900 million won’t fit the bill.