As cities look to create vibrant, walkable downtowns, they frequently turn to linear infrastructure that is often fixed and bulky -- think light rail -- to spur development. It’s presumed that big and flashy projects will attract private investment. But Atlanta’s Beltline shows that simpler infrastructure can achieve the same results.

Atlanta’s Beltline concept began in 1999, after a Georgia Tech student named Ryan Gravel wrote a paper proposing a 22-mile walking trail around the city that follows a former freight track. Under the formal plan, the trail will eventually run through 45 neighborhoods and calls for brownfield cleanups, park refurbishment, streetscape improvements and adding affordable housing. About half of the $4.8 billion budgeted will go to transit, namely a streetcar. In this sense, says Gravel, who now works as an advocate for the project, “the Beltline concept is much more than just a trail.”

That is, if the project is ever finished. To date, Atlanta is behind schedule on streetscape improvements, building affordable housing and starting construction of the streetcar. According to the 2016 fiscal report, only 57 percent of the trail has been built, and only 9 percent of the anticipated budget spent.

But here’s the thing: The Beltline, even in its scaled-down version, has been wildly successful. It has connected previously fragmented parks and mixed-use developments. On a recent night, I walked the one-mile portion that stretches through the bustling Old Fourth Ward. This part of the trail was flanked by mid-rise construction and packed with pedestrians. It’s arguably the most urban part of metro Atlanta. The Beltline has had similar impacts elsewhere, increasing home values in every area through which it passes.

In its uncompleted status, the Beltline costs about $15 million per trail mile and yet has done as much as more expensive linear infrastructure projects have. The waterfront extensions in San Antonio and New Orleans, for example, which spurred similar development, cost $26 million and $67 million per mile, respectively. For comparison, light rail generally costs more than $100 million per mile.

Walking trails may not accomplish all the things that linear infrastructure does. But if walkable and vibrant development is the main goal, they at least encourage that -- and for much cheaper. The Katy Trail in Dallas cost $5.7 million per mile, and the Indianapolis Cultural Trail cost $7.9 million, both generating growth in key areas. The Lynx light rail in Charlotte has attracted development, namely in an area where there also happens to be an adjacent concrete walking trail. It’s unclear which piece of infrastructure has better propelled growth, but Charlotte’s trail draws more than 2,000 users daily, while the portions of the rail line without this trail are less developed.

Atlanta will nonetheless continue toward its more comprehensive vision for the Beltline project, which should be completed by 2030. But its early success as a pedestrian trail shows that further measures might be unnecessary. Because sometimes, attracting growth through linear infrastructure just means finding a right-of-way and pouring some concrete.