Just got this press release:

I-25/Arapahoe Road Interchange Environmental Assessment Update

Project Team To Recommend Elimination of the Costilla Crossing Alternative

As part of the I-25/Arapahoe Road Interchange Environmental Assessment (EA) process, over 25 alternatives for improvements at the I-25/Arapahoe Road interchange have been investigated.  These alternatives were evaluated based on their ability to reduce congestion, improve functional deficiencies and operations, and safety for the traveling public within the I-25 and Arapahoe Road interchange complex.

The project consultant plans to present the recommendations to the project’s technical and executive committees next month for approval.  These committees consist of technical staff and elected officials from Arapahoe County, the City of Centennial, the City of Greenwood Village, the Colorado Department of Transportation, the Federal Highway Administration and the Denver Council of Regional Governments.


Two alternatives will be recommended – one calling for No Action (“do nothing”) and the other would improve the existing interchange without a Costilla crossing of I-25 – for further detailed analysis and comparison in the Environmental Assessment report.

“The recommendations still need to be considered and approved by the Technical and Executive Committees, but the technical analysis behind these findings and recommendations is solid,” said Bryan Weimer, Transportation Division Manager at Arapahoe County.

Improving the existing interchange with a new crossing under I-25 near Costilla, south of Arapahoe Road, was initially recommended by the Arapahoe Road Corridor Study project.  The supplemental I-25 crossing at Costilla Avenue was considered as a means to provide supplemental east-west capacity, with the thought being to provide relief to the congested I-25/Arapahoe Road interchange.

Following CDOT’s completion of interim improvements at the interchange, more detailed traffic analyses were completed.  The analyses found marginal improvement in congestion levels at the interchange, which is one of the main objectives of the project. “The Costilla Crossing would provide only marginal benefit to the interchange traffic flow and would almost double the cost compared to the Improved Partial Cloverleaf Without Costilla.  The team believes the cost and impacts of its construction are too great to justify this marginal traffic benefit.” said Joe Hart, Project Manager with David Evans and Associates, Inc.

Detailed results of the recent interchange alternatives analysis, as well as a soon-to-be-finalized Walnut Hills neighborhood traffic study, will be presented at the second public open house, which is planned for September 8th at Good Shepherd Episcopal Church in Centennial.

More information about the Environmental Assessment can be found on the project web site: www.I25ArapahoeRoadEA.com.