Special to Passenger Transport

In winter, the top level at the Detroit Transportation Corporation’s People Mover station at Joe Louis Arena is buried under ice and snow. Come spring, however, the station roof will turn into an environmental “superhero” as its 6,000 square feet sprout, creating an urban meadow that yields a range of green benefits.

The station’s technologically advanced “green roof” will lower emissions, reduce airborne pollutants and greenhouse gases, provide acoustic buffering, produce oxygen, and help beautify the surrounding community. Green roofs also deflect solar radiation and reduce the energy demands of roof surfaces and building structures, combining to combat the Urban Heat Island effect, which occurs when thermally loaded cityscapes are significantly warmer than their surrounding regions.

The green roof, the first of its kind for the Detroit People Mover system, has been maintenance free after its first year of operation, 2009. The ground cover includes 12 species of plants that are naturally resistant to weed encroachment, wind uplift, and surface erosion. It all grows on a custom-designed product called XeroFlor, which incorporates several layers that retain water, provide drainage, and create a root barrier. Ballast along the roof perimeter maintains the vegetation borders and prevents ponding on the surface.

Planning the layout was key to the success of the project. Full coverage was extremely important, as was selecting a contractor who had experience with the product and its installation, understood Michigan’s four-season weather variables, and could accommodate the challenges of an urban setting.

The green roof also provides insulation, a significant structural benefit in a location like Detroit that experiences wide swings in temperatures. The ground cover prevents heat and cold from penetrating the building.

Photo: Detroit Transportation Corporation Employees of the Detroit Transportation Corporation water and spray the green roof on top of the People Mover station at Joe Louis Arena.