Gov. Andrew Cuomo’s effort to campaign for re-election as a master builder of new infrastructure has been undermined by headlines about New York City’s crumbling subway system. Meanwhile, much less public and political attention is being paid to his management of another major transportation asset: the New York state highway system.

That system, it turns out, is afflicted by a Cuomo-era syndrome that will be familiar to subway riders: a focus on megaprojects, frills and quick fixes at the expense of essential but more costly long-term repairs.

For example, according to the Thruway Authority, fully one-third of the toll-supported Thruway system is rated “poor” or worse on a pavement distress index, while another 28 percent is rated only “fair,” as of 2017.

This, even while Cuomo celebrates a gleaming new $4 billion Thruway bridge across the Hudson, the old Tappan Zee (renamed after his father), and lavishly funded Thruway “welcome centers,” with bid requests now circulating for expensive new Thruway service areas.

The 570-mile Thruway is dwarfed by New York’s 15,000 miles of state-controlled interstates and other highways, which are primarily maintained by Cuomo’s Department of Transportation. So, how are conditions on the DOT system?

As an official matter, no one has an answer. Breaking a promise from the governor in his capital-funding deal with legislative leaders, DOT has failed to make public its annual pavement-conditions report for the last two years.

But based on available data, those highway conditions are about to deteriorate rapidly, according to a study released this year by Rebuild NY Now, an industry coalition advocating higher infrastructure spending. The study’s author, former DOT analyst John Shufon, said pavement conditions had stabilized but over the long term “are going to get worse and worsen considerably.”

Soon after taking office, Cuomo directed DOT to accelerate road and bridge projects as part of his highly touted NY Works program. Repavements soared to 4,400 lane-miles in 2012, a significant increase over prior years, and the share of highway pavements rated “poor and fair” declined to 36 percent.

However, to stretch dollars further, DOT also began relying more on less expensive “thin overlays” of asphalt, which don’t last as long as full reconstructions, according to the Shufon study. And by 2016, the last year for which official DOT ratings are available, resurfacings had declined to just 1,687 lane-miles, barely a third of the 2012 level.

The key indicator of decline cited by Shufon is a measure known as the “paving cycle.” DOT previously set a paving cycle goal of 12 years — meaning it would repave at a rate sufficient to cover the entire system every 12 years. But as of 2016, the pavement cycle had risen to 22.9 years, indicating the state has fallen more than 10 years behind.

The expanding cycle has “allow[ed] thousands of miles of pavement in fair condition to deteriorate into the poor range,” Shufon said. “Deferring treatment increases repair costs exponentially as the pavement structure accumulates more and more damage. This will result in even more strain on future pavement budgets.”

Shufon’s findings could be dismissed as self-serving, since his sponsors include contractors as well as businesses dependent on trucking. But his professional credibility is unassailable — and DOT’s silence speaks volumes.

The study estimated it would take an additional $385 million a year to return the state highway system to a 12-year paving cycle, decrease the reliance on superficial skim coats of asphalt and boost the share of longer-lasting renewal projects. As if conceding the point, soon after Shufon’s study was issued last spring, Cuomo added $100 million to DOT’s paving budget — still well short of what he’d need to spend to get highways back on the right track.

Those figures are small potatoes compared to the billions Cuomo has allocated or promised to the Metropolitan Transportation Authority. Yet compared to the transit agency, DOT has a much better record of delivering improvements on time and on budget.

Questioned about transit troubles during his debate last week with Republican challenger Marcus Molinaro, Cuomo pivoted to new projects. “I’m the most aggressive governor, when it comes to building, in the country,” he declared.

No one has ever questioned Cuomo’s aggressiveness in building new stuff. The question is whether he’s building the right stuff — and maintaining the essential stuff we have.