National Environmental Policy Act (NEPA) Materials

social impacts, such as:

  • land use;
  • community facilities;
  • noise; and
  • air quality.

economic impacts

impacts to environmental resources, such as:

  • wildlife;
  • water resources;
  • parks;
  • historic resources;
  • aesthetic conditions; and
  • water quality.

The NEPA process includes public and agency involvement, and the development of alternatives. The study area is covered in a federal decision document called a Tier 1 Record of Decision, a high-level NEPA document that identifies transportation improvements (capacity, mode, and location) to be made along the I-70 mountain corridor between C-470 and Glenwood Springs. These improvements must be studied in more detail in project-specific Tier 2 NEPA processes such as the Tier 2 document completed for this project.

Westbound Peak Period Shoulder Lane Categorical Exclusion

Context Sensitive Solutions Process

From August 2016 to July 2017, a team studied the Westbound Peak Period Shoulder Lane project via a concept development process. Elected officials in the corridor, representatives of citizen groups, and state and federal agencies worked through the I-70 Mountain Corridor Context Sensitive Solutions (CSS) process to review issues of concern in the mountain corridor and recommend future transportation improvements.

The goal of the concept development process was to identify technical and stakeholder-critical issues, and transportation improvements—with a focus on improvements that could realistically be built in five years, or by 2022. The recommendation of the concept development process for the area west of the Veterans Memorial Tunnels is to proceed with a project that is similar to the I-70 Mountain Express Lane (also known as the Eastbound Peak Period Shoulder Lane).

The I-70 Mountain Express Lane, built in 2015 on eastbound I-70, has proven to be successful; it has reduced travel times by 21 minutes and improved crash clean-up times by four minutes during peak periods when it's in operation.

The concept development process also identified issues of concern, environmental resources to consider and concepts that can be eliminated from further consideration.

Meeting Minutes