US 85 from I-76 to 124th Avenue Project

CDOT, the Federal Highway Administration (FHWA), Adams County, Commerce City, and the cities of Thornton and Brighton have been considering and discussing transportation improvements to US Highway 85 from Interstate 76 (I-76) to 124th Avenue in Adams County. This advisory team has reviewed and evaluated preliminary system alternatives to best improve the transportation network and the US 85/104th Avenue, US 85/112th Avenue, US 85/120th Avenue, and the US 85/124th Avenue intersections.

On March 20, 2018, the advisory team gathered public input on several alternative interchanges for: US 85/104th Avenue, US 85/112th Avenue, and US 85/120th Avenue and US 85/124th Avenue This input will help the advisory team develop the best packages of interchanges that best meets the purpose and need; is responsive to public needs, as well as community and environmental resources.

Purpose & Need

What is the Purpose of the Transportation Improvements?

The purpose of the proposed transportation improvements in the US 85 corridor from I-76 to 124th Avenue are to:

 Improve safety;

  • Reduce existing and future traffic congestion;
  • Improve connectivity for and between transit (bus) bicyclists, and pedestrians; and
  • Improve regional operations for cars, freight, and transit (bus), along US 85 between the Denver metropolitan area and communities in Adams and Weld Counties and provide reasonable access for existing and future land use.

 Why are the Transportation Improvements Needed?

  • Safety - There is a higher than expected number of rear-end crashes at the US 85/104th Avenue and US 85/120th Avenue intersections. The proximity of the railroad to the intersections is not adequate to safely accommodate queues that form between the railroad tracks and US 85 when a train is present.
  • Vehicle and Transit (Bus) Operations - Traffic operations along the corridor and at the intersections are congested today and are expected to worsen by 2040 due to local and regional population and employment growth.
  • Bicycle and Pedestrian Connectivity - Infrastructure for, and connectivity among, multimodal travel modes (transit, bicyclist, and pedestrian) do not meet the existing or future (2040) needs. Corridor demand for biking and walking trips east-west across the US 85 corridor and to access transit along US 85 is expected to increase in the future.
  • Regional Operations and Access Control - US 85 is a regionally significant corridor for regional operations for cars, freight movement (truck and rail), and transit. The spacing distance between the at-grade intersections of US 85/104th Avenue, US 85/Longs Peak Drive, US 85/112th Avenue, US 85/120th Avenue, and US 85/124th Avenue conflict with the corridor’s mobility function.


Most Recent work includes:

  • Gather public input on various alternatives for each intersection (March 20, 2018 at Belle Creek Family Center

Current work includes:

  • Developing package alternatives of various interchange options to best meet evaluation criteria and consider local agency and public input.
  • Conduct periodic advisory team meetings to review and provide input on development of packages

Upcoming Work includes:

  • Evaluate alternatives by conducting a three-tier screening process, resulting in a Preferred Alternative – including priority phasing
  • Conduct an environmental assessment (NEPA) for the funded portion of the Preferred Alternative
  • Develop a 30 percent level of design to further identify anticipated construction costs


Alternatives Development and Evaluaiton: Spring 2018

Environmental Documentation: Summer/Winter 2018

Engineering Design Complete: Summer 2019

When funded, construction may be within 24 months.

Colorado: The Official State Web Portal