Transit, like any other fields, has trends. And today’s hot trend is the streetcar. Portland opened a modern streetcar line in 2001, Tacoma followed in 2003, and Seattle’s Lake Union Streetcar opened last year. Austin, Atlanta, Fort Worth, Dallas, Oakland, Los Angeles, Washington DC, Northern Virginia, and others are studying new lines. In San Francisco (below), New Orleans, Philadelphia, Memphis (above), Dallas, Tampa, and Little Rock, vintage streetcars (or replicas thereof) serve the same function.

So what’s a streetcar? Like light rail, it’s a vehicle running on steel rails powered by an overhead electric wire. In fact, light rail and streetcars are fundamentally the same technology: they’ve shared tracks in several U.S. cities, and in Europe it’s often hard to tell them apart. But in North American practice there are several differences in how the technology is used:

• Streetcars are shorter, narrower, lighter, cheaper, and lower capacity than light rail vehicles.
• Streetcar stops tend to be not only smaller but simpler than light rail stations
• Streetcars often collect fares on board (or don’t collect fares at all), instead of having ticket machines at stations like light rail.
• Streetcars usually run in traffic lanes shared with cars, and they usually use the same traffic control devices (traffic lights or even stop signs) as cars.
• Streetcars are generally built with the idea that it’s acceptable to shut the line down temporarily for utility work. This avoids the need to relocate underground utilities.

The advantage is that these features combine into lower construction cost and less impact than light rail. But you get what you pay for: streetcars in mixed traffic are also slower, less reliable, and lower capacity than light rail. If the Main Street line were streetcar instead of light rail, it would have cost less to build. But it take about half an hour, not 20 minutes, to get from Downtown to the Med Center, rush hour trip times would depend on traffic, and the line would have reached full capacity in June of 2004. If we consider service instead of technology, these new streetcars resemble a local bus route. They are not a substitute for light rail, or even BRT, in reserved lanes.

But there is an alchemy to streetcars: people prefer them to buses even if they do not offer better service. Part of that is the distinctive branding, which distinguishes a streetcar line from the rest of the bus system. Part of it is the certainty of rails: you know exactly where that streetcar is going. And part of it is the lure of novelty and nostalgia. This draws riders onto streetcars who would not have taken a bus. And thus it draws development, too, and that is one of the big lures of streetcars.

Streetcars have slipped into a specific niche in North American transit. They’re a tool for downtown and near-downtown revitalization. They’re intended to promote the construction of lofts and apartments, to draw visitors to cultural institutions and restaurants, and to attract tourists. They’re often constructed outside the regular transit structure, funded through tax increment districts and other local funds, and operated separately form the rest of transit system.

So this is the new U.S. streetcar model: low capacity, low speed, mixed traffic, low impact, low cost, maximum economic benefit. In this model, the ideal streetcar line:

• Serves existing existing or under construction high-density population (so there are riders on day one.)
• Connects to at least one employment center (so the riders have somewhere to go.)
• Serves restaurants, nightclubs, theaters, museums, and other leisure attractions (to draw tourists and locals.)
• Serves areas that have development potential (to generate the tax revenue to pay for the line.)
• Is only a few miles long (so slow speed doesn’t matter as much.)
• Runs on streets that are not too congested (so the streetcars aren’t stuck in traffic.)
• Has a moderate level of transit demand (because that’s what a streetcar can handle.)

Obviously, some of these points are basic to all good transit. But some are very specific. A streetcar has inherent limitations; a good streetcar line is designed to accommodate those. What works in the Pearl District in Portland or South Lake Union in Seattle will not work in every neighborhood, or serve every transit need.

In a small city, streetcars could be the core of a transit system. In a big city, they simply do not have the capacity or the speed for that. But they could be a modest start for rail transit — Dallas had its streetcar line in 1989, seven years before light rail opened — or they could be a local component in a larger rail transit system. That’s the case in Portland, where the light rail line runs one way through Downtown and the streetcar line the other, with a transfer station where the cross, and in San Francisco, where the streetcar line offers local service in a corridor that also has a light rail and heavy rail subway.

The last paragraph could have been written 100 years ago, when streetcars were also a trend. In smaller places, like Houston, they were the transit network; in bigger cities, like New York or Chicago, they were local feeders to subway and elevated lines. Back then, too, streetcars served to stimulate development; neighborhoods were laid out around them, and the lines were often funded through the sale of those lots. Those same neighborhoods remain the places where streetcars work best: they’re close to the core, they’re mixed use, they’re walkable. In many cases, the new streetcar lines are in fact reconstructions of old lines. The streetcar trend is in one sense an admission of error: we would have done well to keep those lines 60 or 80 years ago. And now, in some cases, it makes sense to bring them back.

Read about streetcars in “Street Smart: Streetcars and Cities in the 21st Century” (the first chapter is available as a PDF) and in Paul Weyrich and William Lind’s report.