Glenwood Canyon I‐70: Environmental Concern

Environmental concerns and physical constraints involved in the design of Interstate 70 through Glenwood Canyon, a scenic river gorge in Colorado, resulted in a design approach unique for highway projects. The Highway Act of 1976, which allowed variance from interstate standards, led to a complex and lengthy process to develop a functional and environmentally acceptable design solution. The design process is examined and several elements of the design solution are described, including terraced roadways, cantilevered roadways, retaining walls, tunnels, and a comprehensive revegetation program. The unique design process has resulted in an environmentally sensitive highway design, but the delay in implementation significantly increased the cost of the project.