Streetcars may be sexy and light rail may be alluring, but it turns out that building a bus line is how a city can get the most bang for its buck when it comes to attracting development.

A new study from the public transit advocacy group Institute for Transportation and Development Policy (ITDP), examined the growth of transit-oriented development in 21 cities with various forms of surface public transportation. Compared to streetcars and light rail, the authors found that the bus won out big time in terms of generating high-value development at a low upfront cost.

Though transportation planners have argued over the benefits of buses versus light rail, the ITDP study is the first to show that bus lines can leverage development at great savings to cities.

The key, said the study authors, is investing in a bus rapid transit (BRT) system, like Bogotá's well known TransMilenio. BRT requires a dedicated right-of-way, controlled-access stations, and priority for buses at intersections. It has a lot more in common with a subway than an ordinary city bus, but happens to rely on tires instead of tracks. That means its a lot cheaper to build than any rail system.

Consider Cleveland's HealthLine, a 6.8-mile stretch of BRT with dedicated stations and busways that runs 24 hours a day. Despite opening in the midst of the 2008 economic downturn, ITDP estimated that HealthLine attracted $5.8 billion in transit-oriented development along the route. That's an incredible return on investment, considering that HealthLine cost only around $50 million to build.

"Sure it's cheap," you may scoff, "But it's just a bus, right?" Well, ITDP also scored BRT lines based on measures of capacity, service frequency, access, and average speed, and HealthLine turned out to be the highest-rated BRT system in the U.S. – far ahead of Boston's Silver Line and the Las Vegas MAX. It also beat out light rail and streetcar services such as the Phoenix Metro, Charlotte Lynx, and Portland Streetcar.

According to ITDP, three factors account for the success of HealthLine, or any other surface transit system. First is government support of transit-oriented development, including financing incentives for investment along a transit corridor. Second is the location of the transit line. Downtowns tend to benefit, and weaker real estate markets have more to gain from a smaller investment. Finally, the quality of transit itself determines the amount of investment surrounding a transit line. If BRT can match or surpass a pricey light rail when it comes to quality, it's a solid choice.

And other cities have taken note. *Forbes *reports that ITDP's Annie Weinstock spoke at the city's Metropolitan Planning Roundtable earlier this month regarding a planned BRT line on Chicago's Ashland Avenue.

As far as transit quality is concerned, the Ashland Avenue line could end up the best of its kind in the country. "There’s no gold standard BRT in the U.S. yet," said Weinstock. "But if we continue with the Ashland project on the current trajectory, Ashland could be the first gold in the U.S."