New Diverging Diamond Interchange Coming to Superior and Louisville This Weekend

October 13, 2015 - Metro Denver Colorado/CDOT Region 1 - The McCaslin bridge over US 36 closed while traffic is realigned to the new configuration, Oct. 16-19

SUPERIOR/LOUISVILLE – The Colorado Department of Transportation (CDOT) will close the McCaslin Boulevard bridge over US 36 starting at 9 p.m. on Friday, Oct. 16, for the entire weekend. Once the bridge opens at 5:30 a.m. on Monday, Oct. 19, traffic will be realigned into the new Diverging Diamond Interchange (DDI) as part of the US 36 Express Lanes Project.

Drivers are encouraged to use caution on Monday morning because the traffic pattern will be significantly different across the bridge. When driving a DDI, motorists proceed through a traffic signal at the entrance to the interchange and simply follow their lane to the opposite side of the roadway. Drivers needing to access US 36 from McCaslin Boulevard will turn left at the on-ramp without having to stop again or wait for oncoming traffic to pass. Through traffic proceeds to a second traffic signal and follows their lane back to the right side of the road.

“The DDI is a new way to drive for this area, but the interchange will be signed and striped extremely well so drivers should move through it with no problem at all,” said CDOT Project Director Scott Rees. “This configuration is an innovative way to help traffic move more efficiently through the interchange and onto US 36.”

Drivers can view a video on how to drive a DDI at  The McCaslin DDI is the third in Colorado. The DDI crosses traffic to the opposite side of the road across an interchange so vehicles have unimpeded movements onto the freeway ramps. Left-turn movements, which are a typical challenge with standard four-way interchanges, do not have to cross oncoming traffic in a DDI, helping traffic move more smoothly and increasing safety.

During the closure, which is necessary to put the new alignment in place, access over US 36 on McCaslin Boulevard will not be allowed, but all eastbound and westbound US 36 on- and off-ramps to McCaslin Boulevard will remain open with right turn access only. Left turns and through movements from the ramps to access McCaslin Boulevard will not be permitted during the closure. Alternate routes are advised. Local traffic is encouraged to use Cherryvale Road, 88th Street or Interlocken Loop as alternative north-south routes to travel between Louisville and Superior.

Once the realignment is completed on Oct. 19, there is still work to be done on the McCaslin Boulevard bridge, including ramp paving, sidewalk and median construction, and the bridge arch installation. The bridge is scheduled for completion by the end of this year.   

The US 36 Express Lanes Project is a multi-modal project that is building an express lane in each direction on US 36, in addition to the two free general purpose lanes. The Express Lanes accommodate High Occupancy Vehicles (HOV), Bus Rapid Transit (BRT) and tolled vehicles. In addition, the project is replacing several bridges, building a commuter bikeway, adding BRT improvements, and installing Intelligent Transportation Systems (ITS) for tolling, transit and traveler information, and incident management.  Phase 1, from Federal Boulevard to 88th Street in Louisville/Superior, opened this past summer. Phase 2, from 88th Street to Table Mesa Drive in Boulder, will open in 2016.

For more information about the project, call 303-404-7042 or go to or our mobile website at To receive free email updates during the project, click on the cell phone icon in the upper right corner. You can then subscribe to a variety of lists including “US 36 Express Lanes Project.”