America is full of potholes, slumping levees, and fraying electrical grids. So it may surprise you to learn that the country’s physical infrastructure is actually apparently improving.

For the first time in 15 years, the American Society of Civil Engineers gave the country’s infrastructure a higher grade than it did last time. Congrats, America, you’ve improved from a D to a D+! Soo you’ll still have to repeat the class.

The New York Times reports:

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Some connected trends have led to the shift, according to the engineering organization. It cited a rise in the private financing of public projects and renewed attention from state and local government to kick-start their own projects, rather than wait for Washington to send money. The jump in private investment was instrumental, for example, in the improved outlook for the nation’s rails, according to the report. That evaluation jumped to a C+ from a C-. The group also cited short-term increases in financing — a reference to President Obama’s economic stimulus package, which focused in part on “shovel-ready” projects like road and bridge repair.

“When investments are made and projects move forward, the grades rise,” the report stated.

Gregory E. DiLoreto, the group’s president, said, “A D+ is simply unacceptable for anyone serious about strengthening our nation’s economy,” but he added that the improvement “shows that this problem can be solved.”

In addition to the overall grade, ASCE handed out individual marks for specific kinds of infrastructure: near-failing D- grades for levees and inland waterways, and D grades for drinking water, hazardous waste, roads, transit, and wastewater, among others.

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The highest grade, a shiny B-, was given for solid waste generation and recycling rates, as we’re now composting or recycling more than one third of the crap we toss.

Infrastructure spending can give a real boost to the economy, as The Economist points out: “a study by the University of Massachusetts-Amherst in 2009 found that every $1 billion spent on infrastructure creates 18,000 jobs, almost 30% more than if the same amount were used to cut personal income taxes.”

The Economist laments that declining gas-tax revenue means there’s less infrastructure funding available. It looks at more “creative” —  i.e. private-public-partnership — solutions to America’s failing everything. For example, in Chicago, Mayor Rahm Emanuel (D) isn’t pushing municipal bonds but rather private investments from “foreigners, charities and pension funds” in things like school lightbulbs. Other cities and states are rethinking their gas taxes, and increasing their (really regressive) sales taxes to fund transportation.

The number of “public-private partnership” (PPP) projects under way around the country, although still low by European standards, has jumped in recent years. They include a tunnel under construction in Florida, a commuter rail scheme in Colorado and road improvements in Texas and Virginia. The Center for American Progress, not normally a cheerleader for red-blooded capitalism, reckons it should be possible to mobilise at least $60 billion a year in private infrastructure investment. That would be a huge step up from the paltry total of $10 billion raised through such schemes between 1990 and 2006.

The Economist calls for doing an end run around Congress, and I don’t blame it. But America’s infrastructure needs are in the $250-400 billion-ish range annually, and relying wholly on private companies to invest that amount seems … optimistic. And those PPPs might be nice for classroom lighting, but am I the only one who doesn’t trust multinational companies (and their intrinsic profit motives) to restore our all-important levees?