I-70 Glenwood Canyon Design Concept Study

Glenwood Canyon, Colorado

In 1973, Gruen Associates began work on the eastern half of the I-70. Built in the 1930’s, the antiquated two-lane roadway had become a dangerous bottleneck to east-west travel. Gruen reconciled two goals at odds—meet travel demands and preserve the natural 12.5-mile canyon. Our design separated the highway into two, two-lane roadways with westbound lanes stepped above those heading east to preserve the canyon floor and afford dramatic views toward the Colorado River. The popular Hanging Lake scenic trail was protected by sweeping the highway across the river on long spans that disappear into two 4,000-foot-long tunnels. Much of the roadway is elevated on 40 bridges and viaducts. The four-lane I-70 solution avoided further damage to the beautiful mountain canyon and restored the river’s natural talus slopes and banks. In 2000, President Clinton awarded I-70 the Presidential Design Award as “a model for the design and construction of interstate highways in valued natural landscapes.”