Project Overview

Project Status: Completegreencheckmark

Which issues will this project help address?

During both the summer and winter peak driving seasons, traffic volumes on the I-70 Mountain Corridor are highest on weekends when recreational travelers comprise more than 90% of traffic. In 2010, drivers experienced speeds of less than 20 miles per hour (on average) during return trips to the Denver metro area on Sundays.  Lengthy delays caused some motorists to divert to the frontage road along I-70, directly impacting its functionality to serve as a local access county road.

Why an I-70 Mountain Express Lane?

The I-70 Mountain Express Lane will provide drivers with the choice of a new, more reliable travel lane between Empire Junction and Idaho Springs – one of the most congested stretches of the entire I-70 Mountain Corridor. Hardening the shoulder within CDOT’s existing right-of-way will create an optional tolled third lane during peak travel periods that will help alleviate some of the congestion and keep traffic moving through the corridor, without expanding the footprint of the highway.

What has been done so far?

The Peak Period Shoulder Lane (PPSL) project is part of CDOT’s comprehensive plan to improve the travel experience in the I-70 Mountain Corridor.  During the preliminary design process of PPSL, CDOT completed a National Environmental Policy Act (NEPA) process resulting in a Categorical Exclusion.  The Categorical Exclusion and its supporting technical analysis are available HERE.

PPSL also adheres to the I-70 Mountain Corridor Context Sensitive Solutions (CSS) process, under which a Project Leadership Team and a Technical Team were formed. These groups developed guiding core values that were vital in creating alternate viable solutions for the congested Corridor, ultimately resulting in the PPSL project. Today, both groups continue to be regularly consulted on the status of the project.

Following the design and planning phase, CDOT selected Mountain Corridor Constructors (a partnership of Lawrence Construction Company and URS) as contractors for the construction phase of the project, which began in late July of 2014.

Contact Us
  • Media Contact:
    Stacia Sellers
    Communications Specialist
    Email Stacia.
Planning a Trip?

Slower speeds in construction zones may temporarily delay travel times.  We want to make sure you have access to events, trails and towns that make Colorado great. Use the resources below to help you prepare:

  • Sign up for free email and text alerts with CDOT’s GovDelivery service
  • Call the project hotline (303-223-6581) to listen to the most recent lane closure report
  • Visit


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