Hundreds of residents, cyclists, and Colorado School of Mines (CSM) students, in addition to about 60,000 vehicles, negotiate the US 6/19th Street intersection each day traveling between neighborhoods and downtown, up Lookout Mountain, and between classes and student housing. The proposed interchange provided a link between Lookout Mountain and downtown Golden. The US 6 and 19th Street interchange replaced the existing signalized intersection with a modified diamond interchange featuring a city park and multi-use trails built on the first innovative highway lid in Colorado.
To complete this project in a short time frame and reduce construction risk, Golden set up a Construction Management/General Contractor delivery system for this contract. The timeframe for this project was fast-paced to deliver CDOT 1601 Process approval and construction documents for a $25 million interchange in 1.5 years. The project was a federally funded CDOT Local Agency Oversight Project requiring CDOT oversight along with CDOT right-of-way, environmental and utility clearances.
The team studied several alternatives to mitigate conflicts between vehicles and pedestrians and bicyclists. The Study recommended a free-left modified diamond as the preferred alternative. It provides separated multimodal connectivity and park-like amenities with a “lid” overpass structure over US 6. A unique geometric configuration keeps pedestrian and bicycle traffic separated from vehicular traffic and provides efficient traffic operations at the ramp terminals without the use of traffic signals. The primary movements between downtown Golden, Denver, and Lakewood all move freely without stopping. CSM students now walk from home to class through a park built above US 6, rather than crossing a busy multi-lane highway. The park provides neighbors with quiet seating areas to enjoy mountain views, provides cyclists with bike lanes and wide concrete trails to ride through the park and up Lookout Mountain, and minimizes noise in the adjacent neighborhoods with a depressed US 6 alignment and low-speed design of 19th Street.
The project utilized an extensive stakeholder and public involvement program including the City of Golden, CDOT, Colorado School of Mines, and Jefferson County.
- 2019 Environmental Excellence Award, Federal Highway Administration
- 2019 ACEC National Grand Engineering Excellence Award
- 2019 ACEC Colorado Grand Conceptor Engineering Excellence Award
- 2017 WTS Colorado, Innovative Transportation Solution of the Year
- 2018 APWA Project of the Year, Transportation $5M but less than $25M
- 2018 AASHTO America’s Transportation Awards, Best Use of Technology & Innovation, Medium Project
- Cover story in Fall/Winter 2017 Colorado Public Works Journal
- Featured in June 2015 Civil Engineering Magazine