Superior Diverging Diamond Interchange
What are the goals?
The existing interchange at McCaslin Boulevard and US Route 36, which lies between the Colorado towns of Superior and Louisville, cannot accommodate the increasing traffic of the growing Denver suburbs. Faced with budget cuts and limited options, rebuilding the intersection was not an option. The chosen solution: retrofitting the existing overpass into a diverging diamond interchange.
The new interchange alleviates congestion by temporarily crossing the parallel directions of traffic on the overpass as the span traverses the interstate and then allowing the traffic to return to its appropriate side after exiting the overpass. Such a system eliminates the need for left-hand turns that cross the flow of traffic; a major cause of both congestion and accidents. Additionally, the design uses less land by eliminating the need for special turning lanes, allowing for expanded space for pedestrians and traffic flow.
How is the project being executed?
The cities of Superior and Louisville, Colorado initially conducted studies to find a solution to the McCaslin bridge bottleneck that separated the two communities. Both cities joined forces with Colorado Department of Transportation and the Denver Regional Transportation District (RTD) to finance the $12.5 million project. Superior is financing the largest share of the project with a $5 million municipal contribution. The project avoided high costs, by preserving and repurposing the existing infrastructure.
In addition to improving traffic flow, Colorado's newest DDI will have several other features to alleviate traffic congestion and improve safety. A series of bike paths and shortened crosswalk crossings will lower the risk of accidents involving pedestrian. A new RDT stop, the Denver Metropolitan Area's bus service, will avoid the interchange all together through the use of special ramps, saving commuters an average of 3 minutes each way.
Route 36 Commuting Solutions
Presented at the NLC Congress of Cities 2015
Clint Folsom, Mayor
City Solutions and Applied Research