CDOT Rings in the New Year with Completion of State’s Second Diverging Diamond Interchange on the McCaslin Boulevard Bridge

January 8, 2016 - Denver Metro/CDOT Region 1 - A ribbon-cutting ceremony was held Jan. 7, to signify the official opening of the McCaslin Blvd bridge over US 36.

LOUISVILLE/SUPERIOR, CO – The Colorado Department of Transportation (CDOT), High Performance Transportation Enterprise (HPTE), Plenary Roads Denver, Town of Superior, City of Louisville, and other project partners joined the US 36 Express Lanes Project team to officially open the state’s second Diverging Diamond Interchange (DDI) at the McCaslin Boulevard bridge over US 36. A ribbon-cutting ceremony was held Jan. 7, to signify the official opening of the DDI bridge.

Locally known as the “innovation corridor,” the US 36 Express Lanes Project was built with the well-defined strategy of moving traffic more efficiently. One innovation to help meet this goal was the addition of the DDI on the McCaslin Boulevard bridge in Louisville/Superior. The DDI, which was not originally part of the Phase 2 scope, will be paid for by the City of Louisville, the Town of Superior and the Regional Transportation District (RTD), after a traffic study was conducted to learn more about the efficiency and effectiveness of a DDI and to consider other alternatives.

The DDI is one of 34 DDIs in the country but only the second in the state of Colorado. The state’s first DDI in Grand Junction opened in early 2014. The DDI helps move traffic across the bridge more efficiently by crossing traffic to the opposite side of the road across the interchange so vehicles have unimpeded movement onto the highway ramps. In addition, DDIs increase left-turn capacity, accommodate more traffic with fewer lanes and reduce delays by using a two-phase signal as opposed to traditional traffic signals. The bridge, which began construction last year, will still have some construction over the next few months to finish sidewalks, landscaping and striping, but drivers can experience the benefits now.  

“Opening the state’s second DDI is truly a reason for celebration,” said CDOT Executive Director Shailen Bhatt. “We know construction is frustrating for drivers, but now, anyone crossing US 36 between Louisville and Superior can do so quicker and safer. DDIs will be more prevalent in Colorado and, in fact, we have one opening later this year in Colorado Springs.”

In addition to the new DDI, new bus ramps were built under the on- and off-ramps to US 36, allowing buses to quickly get on and off the highway without merging with general traffic, saving time for bus riders and improving the Flatiron Flyer BRT service, which began on Jan. 3, 2016.

For more information about the project, please visit