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Interstate 470 Colorado

Travelers on C-470 north catch a glimpse of Red Rocks beyond the cut SH 8 takes between Mount Glennon and Dinosaur Ridge. The freeway runs along the Hog Back north from Ken Caryl Ranch to Golden. Photo taken 08/11/14.

History

Interstate 470 was the planned loop around the Denver metropolitan area south from Interstate 70 at Golden and east to Littleton, Centennial and Interstate 25 in Lone Tree. The route, which today forms the southwestern quadrant of the Denver Beltway, was adopted in 1969 by the Denver Metropolitan Area Transportation Study. Interstate 470 was added to the Interstate Highway System under the Federal Highway Act in December 1968.1 The route went through various studies through 1972, when the final environmental impact statement was released and submitted to the Federal Highway Administration (FHWA).

As was the case with several Interstate Highways studied in the early 1970s, the environmental impact statement brought controversy. Governor Dick Lamm, who was elected on a platform that included the elimination of Interstate 470 from Denver metropolitan area transportation plans, created the Interstate 470 Ad Hoc Commission. The commission studied the route and conducted public sessions. In December 1976, the commission recommended that I-470 should be withdrawn from the Interstate Highway System and an at-grade parkway (Centennial Parkway) be constructed in its place.1 Shortly thereafter, the Colorado Department of Highways concurred with the findings of the commission. On June 23, 1977, the FHWA approved eliminating Interstate 470.1

1975 Gousha Map of Denver showing proposed Interstate 470.

Funds previously allocated for I-470 were earmarked not only to the Centennial Parkway corridor, but also to improvements on U.S. 85 (Santa Fe Drive) and other transportation improvements throughout the region. Construction got underway for Centennial Parkway in 1982, as Colorado 470. Design changes made by that time included interchanges in place of signalized intersections.

Referred to as C-470, Centennial Parkway opened in stages with the last section completed in October 1990. While Colorado 470 is a freeway, there are right in right out (RIRO) connections along westbound at Colorado 75 (Columbine Hills) and Hampden Avenue (Bear Creek Lake Park).

Starting in the 1990s and continuing through the 2000s, the Denver Beltway was extended east to Aurora and north to Broomfield as a toll road via Extension 470 ("E-470") and the Northwest Parkway. These sections were never considered for inclusion in Interstate 470.

Highway Guides

Western Terminus - Interstate 70 and U.S. 6 at Golden
Perspective from C-470 west
C-470 travels 1.5 miles north from Alameda Parkway and Rooney Valley to Interstate 70 at Exit 1. Photo taken 08/11/16.
Three lanes rise along the west slopes of Green Mountain through to Interstate 70 west to Genesee Park and Grand Junction and east to Wheat Ridge and Denver. Photo taken 08/11/16.
The C-470 mainline extends north to U.S. 6 (6th Avenue) and Johnson Road in Golden while two lanes part ways for I-70 (Exit 1). Photo taken 08/11/16.
Commuters headed to Downtown Denver join I-70 east just ahead of the 6th Avenue freeway for U.S. 6 east. I-70 west continues west through the Jefferson County suburbs through to the Summit County line and Idaho Springs. Photo taken 08/11/14.
Historic perspective from C-470 west
Completion of the Alameda Parkway interchange (Exit 2) in July 2008 included a new acceleration lane for C-470 west in place of the one-mile overhead for Interstate 70. Photo taken 08/28/04.
The former mainline of C-470 was converted into a collector distributor roadway for Exit 1by 2006. Traffic for U.S. 6 and I-70 now splits a half mile beyond this monotube assembly. Photo taken 08/28/04.
Control cities for Interstate 70 remain the long distance destination of Grand Junction and nearby Denver with sign replacements. Photo taken 08/28/04.
A single lane continued beyond the loop ramp for I-70 west to the C-470 ramps for U.S. 6. Photo taken 08/28/04.
South Table Mountain rises to the north as C-470 concludes with an at-grade ramp to U.S. 6 (6th Street) east and a flyover for U.S. 6 west toward Clear Creek Canyon. Photo taken 08/28/04.
Eastern Terminus - Interstate 25 and E-470 at Lone Tree
See the Colorado 470 guide for photos of the east end.

Sources:

  1. The Story of I-470, C-470, E-470, W-470, and the Northwest Parkway (Matthew Salek). http://www.mesalek.com/colo/denvers470.html

Page Updated April 20, 2017.

Mileage

State Colorado
Mileage 28.162*
Cities Golden, Lakewood, Littleton, Centennial, Lone Tree
Junctions I-70, I-25
Source: * - 26.195 miles for Route 470A and 1.212 miles for Route 470W.
Colorado Department of Transportation Straight Line Diagram Tool
Looking north from C-470 at the Soda Lakes toward the Hutchinson Green Mountain Village and Rooney Valley (Solterra) developments against Green Mountain. Photo taken 08/11/16.
One of the key points made by Colorado Governor Dick Lamm made in opposition to Interstate 470 was that the freeway would be the catalyst for suburban sprawl. Despite being built with just four lanes, Centennial Parkway ultimately fueled the suburban boon in Jefferson County and Lakewood.