Forget the bus and the skip the train, the future of American urban transit could be the old-fashioned streetcar.

Signs of what U.S. Transportation Secretary Ray LaHood has called a “streetcar revival” are popping up all over the country.

In St. Paul, officials are embarking on a yearlong, $250,000 study of potential streetcar routes, following the lead of neighboring Minneapolis, which has spent over $1 million studying two possible streetcar corridors.

The Twin Cities are among more than 80 U.S. cities – including Detroit and St. Louis – that are looking into street cars, according to the American Public Transportation Association.

And several cities have been building or expanding their systems over the last decade, including Atlanta, Portland, Ore., Seattle, Washington D.C. and New Orleans – a city that boasts the oldest continuously operating streetcar in the world.

The turn to streetcars is being led not just by nostalgia and the needs of an increasingly urban populous, but by a broader desire to spark economic activity, Governing reports.

“When Portland built its line in 2001, the city hoped it would encourage transit-oriented development,” Governing reported. “The line has done just that. Today, it is credited with leading to $3.5 billion in new construction, 10,000 residential units, and more than 5 million square feet of office and hotel space.”

A recent study of the Washington D.C. system also suggested that streetcars induced development, boosted property values and brought people closer to mass transit – factors that created as much as $291 million in new tax revenue for the city.

Such economic considerations are a relatively new factor in deciding how federal transportation dollars are spent.

In 2010, the Obama administration opted to add economic development potential and social benefits to the list of factors to be considered when deciding which transportation projects to support.

Since then, the DOT has provided nearly $350 million in funding for 11 streetcar and urban circulator projects across the country.

The resurgence in activity comes 50 years after streetcars nearly disappeared from the American landscape as automobiles crowded the streets and mass transportation gave way to buses.

But proponents tout them as more than just history-evoking tourism gimmicks. Besides the potential economic ripple effect, proponents say streetcars offer more universal accessibility and suggest their ability to attract urban dwellers reduces the need for car travel, cutting carbon emissions.

A 2010 study of a proposed $128 million system with seven streetcars and five miles of tracks in Cincinnati suggested the project could reduce vehicle miles traveled by over 1.2 million in its first year, saving more than 74,000 gallons of gasoline. The study also suggested the streetcar could eliminate nearly 14,000 tons of carbon emissions over 20 years

Not every streetcar project has been a boon, however. Tampa, Fla. officials received a report this week suggesting their streetcar system – supported through special assessments, ridership fees and an endowment – was plagued by financial mismanagement and hefty insurance costs.

Randal O’Toole, a senior fellow with the Cato Institute and the author of Gridlock: Why We’re Stuck in Traffic and What to Do About It, also panned the promise of streetcars in a recent commentary in the Atlanta Journal Constitution.

O’Toole, a proponent of buses, described streetcars as an “obsolete technology” that require more energy than cars and have a specious economic development record supported primarily by public subsidies.

“There is a good reason why all but six of the more than 800 American cities that once had streetcars replaced them with buses: Streetcar infrastructure is expensive to build, expensive to maintain and must be rehabilitated at high cost about every 30 years,” he wrote.

LaHood, though, doesn’t seem to be backing down. After attending a streetcar conference in Portland earlier this month, he continued to promote the promise of streetcars on his blog, writing that their revival “means greater mobility and more American jobs.”