The Brooklyn Bridge is one of many listed as structurally deficient. REUTERS/Lucas Jackson

A cab drives north on Water Street in Downtown Manhattan, its nightcap-filled passenger bearing work-weary bones. It swings a left onto the Brooklyn Bridge, cutting around the entrance ramp's construction barriers, then hums across the relatively smooth 6,000-foot span. Neither driver nor passenger has reason to doubt the bridge's condition. It's been there for 128 years. The construction crews? They dot Manhattan streets like pot holes.

But the presence of hardhats and heavy equipment nods to a greater issue: the Brooklyn Bridge is in need of tender love and care, along with 68,841 other U.S. bridges, according to data from the Federal Highway Administration's National Bridge Inventory compiled by Transportation for America, a nonprofit coalition that advocates infrastructure investment.

Structurally deficient is the technical term; an unfortunate, panic-inducing phrase that doesn't necessarily mean looming peril, but sure does sound like it. It is defined by a lackluster state for any of a bridge's three main components: the substructure (support from below); the super-structure (support for the span from above); or the deck, which is driven across. There are degrees of structurally deficient but of course, as time passes, deficiencies could become truly perilous.

America's Bridges: Heavy Use

America's bridges are crossed an average of 4 billion times every day; 282 million of those treks involve structurally deficient spans. As America's infrastructure ages, the ranks of deficient bridges will grow, doubling by 2030 if not addressed, according to Transportation for America.

The state of the bridges mirrors a national decline in the state of infrastructure, a problem which House Transportation and Infrastructure Committee member U.S. Rep. Jerrold Nadler, D-N.Y., said affects the entire nation.

If your infrastructure becomes noncompetitive, your economy also is noncompetitive, he said.

The nation's mounting infrastructure problems have crept up as a result of lax oversight of how states spend federal money, and the sheer size and age of the system, according to Transportation for America's director of communications, David Goldberg .

There are sexy projects that have political champions that often take precedent, he said. That's part of the problem.

That sexiness typically overrides the stale goal of bridge repair. Yet the nation's bridges have aged in the shadows rather gracelessly. The average design life of a typical bridge is 50 years, a figure most are approaching and a third have already passed.

You've got to fix what you've got before you build something new, said U.S. Rep. Blake Farenthold, R-Texas, who sits on the House Transportation and Infrastructure Committee.

A $70.9 Billion Price Tag

Fixing all the deficient bridges bears a $70.9 billion price tag, according to FHWA estimates. But in a political and economic era where consensus and money are in short order, the odds of a wholesale fix are slim to none. Lawmakers have until the current spending program runs out in March to find a fiscal solution. If their current efforts are any indication, good luck.

Last week put into focus Congress's seeming inability to agree on anything, as the Senate killed two bills aimed at fixing infrastructure: one a $60 billion chunk of President Barack Obama's jobs bill that would have required an increase on marginal tax rates for the rich; the other a Republican bill that would have extended current infrastructure funding for another two years.

Senate Democrats and Obama blasted Republicans for holding up a bill they said would create jobs and make much-needed infrastructure improvements and expansion. While $70 billion is needed to fix bridges alone, all the bills proposed fall short of the figure and were aimed at infrastructure spending as a whole.

House Transportation Committee Chair John Mica has introduced legislation to fund infrastructure work for the next six years. REUTERS/Mannie Garcia

Another plan, on offer by House Transportation and Infrastructure Committee Chairman John Mica, R-Fla., would extend funding by six years and spend about $285 billion. Republicans are pitching the effort as an alternative jobs bill.

We haven't come up with a solution, but we will find a way to fund at least current (spending) levels, Mica told the AP.

U.S. Sen. Barbara Boxer, D-Calif., has proposed a two-year, $109 billion bill of her own, a competing measure to Mica's.

Time for New Bridge Funding Method?

A true fix, many believe, will come from a wholesale change in the way revenue for infrastructure is generated -- and it may be painful.

Since the Interstate Highway System's inception in the 1950s, a gas tax has provided a direct funnel of funds from drivers' pockets to infrastructure creation and repair. Considered a users fee, the tax was adjusted for inflation and to meet demand until 1993, when it reached its current level of 18.3 cents per gallon sold.

In the time since, six-year spending bills have continued the nation's infrastructure investment, but according to Nadler, without an adjustment for inflation, the gas tax has fallen well short of the needed funds to even maintain the status quo, let alone expand or repair.

It's easy to see why the 18 years have passed without a gas tax adjustment -- increasing a tax on an already costly commodity is tantamount to political suicide. Yet after adjusting for inflation, along with the economic downturn's curtailment of driving, the real revenue from the fuel tax has fallen.

The gas tax is being held down on what it can yield by increasing efficiency of the fleet, and higher gas prices have meant that people are driving less, and the growth in driving has leveled off, Goldberg said. The gas tax doesn't go as far as it used to.

Nadler said an adjustment in the gas tax was necessary but skipped over.

When all of public policy is directed towards saying, 'Let's use fewer gallons,' your system ultimately has to fall apart, he said. You either have to bring in a new revenue source or adjust the gas tax.

Goldberg also suggested broadening the potential revenue sources for infrastructure spending, and making the funding steadier.

House Speak John Boehner, R-Ohio, spoke of a different source of infrastructure funding in September: an expansion of oil and gas drilling.

I'm not opposed to responsible spending to repair and improve infrastructure, Boehner told the Economic Club of Washington, according to The Hill. But if we want to do it in a way that truly supports long-term economic growth and job creation, let's link the next highway bill to an expansion of American-made energy production.

Boehner said infrastructure and energy make for a natural marriage, as the infrastructure is needed to bring oil and gas to the market.

Regarding Bridge Repair, Grover Norquist Is in the Way

Nadler said the gulf between the two parties has widened because of Republicans' seeming allergic aversion to raising tax revenue, as they worship at the altar of Grover Norquist.

Farenthold, a freshman Republican averse to increased spending, said it's time the committee looked at other ways to address infrastructure issues.

You're going to be hard pressed to find new revenue, he said. You're just in an overall climate where it's necessary to tighten the belt. There are some options where we can levarge the money better.

Overregulation leads the cost of federal highway work to skyrocket in comparison to major state arteries, Farenthold said.

The biggest thing that surpised me was how we shoot our own selves in the foot with these excessive regulations, he said of his early days on the committee. A state highway isn't a whole lot different than a federal one.

The chance of any substantive plan remains slim, leaving some states to address their crumbling bridges themselves.

Of the 50 states, Pennsylvania has the highest percentage, 26.5, of structurally deficient bridges. Gov. Tom Corbett has aggressively sought to fix the problem, commissioning a Transportation Funding Advisory Committee to explore ways of removing the state's dependency on federal money for infrastructure work.

We kind of have to look at some long-term funding, and not just federal funding because it's too unpredictable, Pennsylvania Department of Transportation spokesman Dennis Buterbaugh said.

From 2008 to 2011, Pennsylvania reduced its number of structurally deficient bridges by 16 percent, Buterbaugh said. No small feat in a state where more than 300 bridges become structurally deficient every year.

The fixes have been tough to endure. At the moment, 42 bridges statewide are closed, their repair funded by money that typically would be used elsewhere.

Some of the money we're diverting to bridge rehabilitation could be going to capacity enhancement and road maintenance, Buterbaugh said. We are assuming federal funding will be minimal. We have to thinking Pennsylvania is an island and let's see what we can do for ourselves.

For Now, Only Stopgap Measures Are Possible

The best Americans can hope for from the federal government, it seems, are stopgap measures until the time is right for a national rethinking of how we fund our highways and bridges.

Looking forward, we've got a pretty significant choice to make, Goldberg said. If we have a laissez-faire system that keeps supplanting repairing what we've got, we've got a big problem to deal with. An upfront infusion that did have an emphasis on rebuilding would be extremely beneficial and helpful. But we really do have to think beyond that. If the priorities aren't shifted, we could have a near-term infusion for job creation and then a couple of years down the line we'll have a major problem on our hands.

And New Yorkers can hope against a fate similar to the residents of Louisville, Ky., and New Albany, Ind. There, the shutdown of the Shermon Minton Bridge for major repairs has caused traffic and economic headaches that will last several months.

Goldberg said the issue of structurally deficient bridges will take years to address, which may not come to pass if the discussion on Capitol Hill remains mired in its own deficiencies.

This is a very difficult political environment. Even an issue like infrastructure, which hasn't been terribly partisan, is more riven with a lack of consensus on how to move forward, Goldberg said. We feel that if cooler heads prevail, this issue will rise to the top. Rhetorically it's a shared goal. We'll see how sincere it is when the time comes to make a decision.