green spaces built on highway overpasses. emily has more. reporter: there is a new push to add traffic to atlanta s notoriously strapped highways that his foot traffic. proposals in the city suggest building up straight green space for pedestrians. we essentially fill in a hole over a highway. reporter: the most extensive project is dubbed the stitch. planters from the non- profit atlanta progress one to cap a three-quarter mile stretch of the downtown connector with urban parks. festivals, gatherings, picnics, throwing a frisbee and i think it s hard to envision in this particular space but it can happen and it has happened in other cities. reporter: dallas part of the va with its park in 2012 and since then more than 6 million people have visited. designer says several dozen cities are currently considering deck parks in cities like seattle, denver and pittsburgh.