Driving through Glenwood Canyon is one of the thrills when visiting Colorado. The highway was designed to hug and flatter the canyons walls, not plow through with disregard to the natural beauty. There was quite a bit of heated discussion before the State of Colorado was ready to contribute funding because the engineering to protect the canyon also cost much more than just ramming roads in. The above coordinates are from the Civil Engineering Award plaque found at the Grizzly Bear Rest Stop, though I would think any visit to the canyon would count since this section of road is over 12 miles long.
A wonderful article exploring the engineering and political costs of the road may be found at (
visit link) . "The final design consisted of a predominately elevated roadway including 40 bridges and viaducts stretching more than 9.5 kilometers (6 miles) between sections of roadway. The highway also has 24 kilometers (15 miles) of retaining walls and a 1,200-meter (4,000-foot)-long tunnel with bores for traffic in both directions. The retaining walls are secured with ground-anchored tiebacks and soil anchors, and the highway is paved with cast-in-place, post-tensioned pavement slabs cantilevered 1.8 meters (6 feet) beyond the retaining walls.... The project won more than 30 awards, including the 1993 Outstanding Civil Engineering Achievement Award from the American Society of Civil Engineers."
"Dubbed by some as “the crown jewel of the Interstate system,” the Glenwood Canyon portion of I-70 winds through the sheer cliffs of a rugged and beautiful landscape. Engineer designers worked with the public to address aesthetic and environmental concerns so that the important corridor westward of Denver would not simply be “blasted out of the landscape.” Begun in 1964, construction go-aheads faced various delays, with work completed in 1993. Engineers had to deal with unstable talus slopes, which were pumped full with grout when a solid base for bridges was needed. The highway employs a crack-free pavement with a 100-year design life." (from
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"Glenwood Canyon has served as the primary transportation artery through the Rocky Mountains, even before the creation of U.S. highways. Railroads have used the canyon since 1887 and a dirt road was built through the canyon in the early 1900s. The first paved road was built from 1936 to 1938 at a cost of $1.5 million (equivalent to $23 million today).
With the Eisenhower Tunnel finished, the last remaining obstacle for I-70 to be an interstate commercial artery was the two lane, non-freeway portion in Glenwood Canyon. Construction had started on this section in the 1960s with a small section opening to traffic in 1966. The remainder was stopped due to environmentalist protests that caused a 30-year controversy. The original design was criticized as "the epitome of environmental insensitivity". Engineers scrapped the original plans and started work on a new design that would minimize additional environmental impacts. A new design was underway by 1971, which was approved in 1975; however, environmental groups filed lawsuits to stop construction, and the controversy continued even when construction finally resumed in 1981. The final design included 40 bridges and viaducts, three additional tunnel bores (two were completed before construction was stopped in the 1960s) and 15 miles (24 km) of retaining walls for a stretch of freeway 12 miles (19 km) long. The project was further complicated by the need to build the four-lane freeway without disturbing the operations of the railroad. This required using special and coordinated blasting techniques. Engineers designed two separate tracks for the highway, one elevated above the other, to minimize the footprint in the canyon. The final design was praised for its environmental sensitivity. A Denver architect who helped design the freeway proclaimed, "Most of the people in western Colorado see it as having preserved the canyon." He further stated, "I think pieces of the highway elevate to the standard of public art." A portion of the project included shoring up the banks of the Colorado River to repair damage and remove flow restrictions created in the initial construction of US 6 in the 1930s.
The freeway was finally completed on October 14, 1992, in a ceremony covered nationwide. Most coverage celebrated the engineering achievement or noted this was the last major piece of the Interstate Highway System to open to traffic. However, newspapers in western Colorado celebrated the end of the frustrating traffic delays. For most of the final 10 years of construction, only a single lane of traffic that reversed direction every 30 minutes remained open in the canyon. One newspaper proudly proclaimed "You heard right. For the first time in more than 10 years, construction delays along that 12-mile (19 km) stretch of Interstate 70 will be non-existent."
The cost was $490 million (equivalent to $800 million today) to build 12 miles (19 km), 40 times the average cost per mile predicted by the planners of the Interstate Highway system. This figure exceeded that of Interstate 15 through the Virgin River Gorge, which was previously proclaimed the most expensive rural freeway in the United States.[32] The construction of I-70 through Glenwood Canyon earned 30 awards for the Colorado Department of Transportation, including the 1993 Outstanding Civil Engineering Achievement Award from the American Society of Civil Engineers. At the dedication it was claimed that I-70 through Glenwood Canyon was the final piece of the Interstate Highway System to open to traffic. For this reason, the system was proclaimed to be complete.) (excerpted from (
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Also visit Waymark (
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