Here in Washington, many residents are eagerly awaiting the opening of the city's perpetually-delayed streetcar line. And they'll have to keep waiting. The city is refusing to set a date for when the line will open, the Washington Post reported last week.

For all the sound and fury accompanying DC's streetcar line, you'd think it was a massive undertaking, but this two-mile route is in fact dwarfed by streetcar systems nationwide. From tiny systems like Kenosha's 1.7-mile loop to Philadelphia's massive system, Greater Greater Washington has compiled a graphic of America's streetcar systems, to scale.

Washington's two miles of streetcar are part of an ultimately much larger system that as planned, would comprise 37 miles of streetcar routes. Not that that system looks likely to be finished anytime soon (or, perhaps, ever) — the city council is considering drastically cutting the project down in size, a local NBC affiliate reported recently.

DC's project is part of a nationwide boom in streetcar construction. In addition to the existing systems, the American Public Transportation Association counts seven streetcar projects (including the DC line) and expansions that will open in 2015.

And while the streetcar craze continues, the debate over the benefits of streetcars rages on. It is true that streetcars, like any public transit system, have all sorts of benefits for the cities they serve — they can cut down on traffic and boost the environment by taking cars off the road, and they promote economic growth and social mobility by connecting people with jobs.

But cities can (and do) often screw up streetcar projects, as Matt Yglesias wrote earlier this year, and they do it by not giving them dedicated lanes. Mix a streetcar in with the rest of traffic, and it's hard to see its benefits over a bus — it moves at the same speed as the rest of traffic, meaning it not only gets stuck when everyone else does, but it can't move to get around other cars that are in its way. Give a bus a dedicated lane and it can do a lot of the same things a streetcar does...without the extra costs (and endless waits) that constructing a streetcar system brings with it.

[h/t Emily Badger]