Over 10% of bridges in New York are structurally deficient, according to the ARTBA.

Nearly 10% of nation’s bridges ‘structurally deficient’

Thanks to more highly refined automotive components and cutting-edge technology, the average vehicle today is holding up to the wear and tear that a life spent on the road can bring.

Unfortunately, the same can't be said for the nation's transportation infrastructure. Tens of thousands of roads and bridges are in rough shape, so much so that they may need to be replaced entirely if not more effectively maintained – and soon, newly released data suggests.

An estimated 58,500 bridges countrywide are considered "structurally deficient," according to a recent report from the American Road & Transportation Builders Association. Though that's roughly 2,600 fewer run-down bridges from 2014, it's still cause for concern, industry experts emphasize.

Current investment in bridge maintenance not going to cut it

Much of this is due to the amount of money – or lack thereof – going toward keeping bridges in good working order. ARTBA noted that at the current pace of investment, it would take over two decades for all of the structurally deficient bridges to be upgraded or replaced.

Presently, there are more than a half-million bridges nationwide. Of these, approximately 9.5% are in severe disrepair.

Unsurprisingly, the United States' most regularly used bridges are in particularly bad shape, many of them household names. For instance, the Brooklyn Bridge in New York, the Centennial Bridge in Illinois, and Washington, D.C.'s Memorial Bridge were all on ARTBA's dangerous bridge list.

Alison Premo Black, ARTBA's chief economist, told ABC News that in order for a bridge to be classified as structurally deficient, it has to fail in one of three subcategories: Deck, superstructure, or substructure. If regarded as inadequate, it basically means that road crews need to go to work on them before they become too dangerous to drive over.

"These bridges need to be fixed so they don't get to a point where they are unsafe for the traveling public," Black explained.

In several states, 15% or more of the bridges there fall into the structurally deficient category. This includes 23% in Rhode Island – the largest percentage in the country – 21% in Pennsylvania, 20% in South Dakota and 16% in Oklahoma, North Dakota, and Nebraska.

85% of California bridges built before 1970

Bridges' poor performance is largely due to the fact that many were built 30, even 40 years ago. In California, for instance, 85% of the state's bridges were originally developed prior to 1970.

That being said, Black stressed that conditions are getting better, as several of the structurally deficient bridges identified as such have been taken care of. This includes 7,200 bridges that were rebuilt, repaired, or replaced in 2014.

Plenty of work remains, though. Safety officials have called on lawmakers – federal, state, and local – to invest more financial resources into infrastructure, obtaining funding through taxes on gasoline and toll hikes. Black noted that this can help fill in the gaps where the five-year federal highway bill lacks funding.

"The funding made available won't come close to making an accelerated national bridge repair program possible," Black warned. "It's going to take major new investments by all levels of government to move toward eliminating the huge backlog of bridge work in the United States."