I-70 Westbound Peak Period Shoulder Lane

A project team is studying a proposal to build an Express Lane on a 12-mile stretch of westbound I-70 in the mountains (between Empire Junction and the Veterans Memorial Tunnels), similar to the existing I-70 Peak Period Shoulder Lane on eastbound I-70. The team plans to complete the study—a National Environmental Policy Act process—in fall 2018. Construction is planned to begin in late spring or summer 2019, assuming funding is identified.

Proposed Improvements

The project proposes adding a 12-mile tolled westbound peak-period shoulder lane between the Veterans Memorial Tunnels (MP 243) and the US Highway 40 and I-70 interchange (Exit 232). Proposed improvements include:

I-70 Modifications
The team proposes I-70 be resurfaced and widened by small amounts in select areas to convert the shoulder into a tolled travel lane during peak periods (Peak Period Shoulder Lane, PPSL). This would create three travel lanes during peak periods. New emergency pull-outs would be added to be used for emergencies and enforcement. The two general purpose lanes would remain open, and free, to all travelers at all times.  During non-peak periods, the PPSL would be closed to traffic and function as an extra-wide shoulder.

Similar to the eastbound I-70 Mountain Express Lane, the westbound PPSL would use transponders and license plate tolling. Pricing would be adjusted to achieve the desired lane use and provide drivers with a reliable travel time option through the corridor during peak periods. The operational days and times would coincide with peak travel periods on weekends and holidays.

US 40 Interchange Ramps
Ramp improvements at the US 40 interchange would reduce vehicular collisions with wildlife. Every year, an average of eight wildlife-vehicle collisions are reported to law enforcement in this area. Improvements may include removing vegetation to improve sight distance and guardrail additions to create a barrier for wildlife.

State Highway 103 Interchange Improvements
Ramp geometric improvements would address sight-distance and drainage problems. The on-ramps and connections from them to the Idaho Springs street system would be compatible with a potential new transit center/parking garage being planned by the city.  New bus stops and shelters would provide a safe place for passengers to get on or off CDOT's Bustang interregional bus service, Clear Creek County's local bus service, and the Greyhound bus.

Rockfall Mitigation
Rockfall mitigation measures would be implemented to prevent rocks or other debris from falling on travel lanes or shoulders and reduce the potential for crashes and travel disruptions. Westbound I-70 is frequently affected by rockfall in the travel lanes, and in 2014, I-70 was closed in both directions just west of Idaho Springs for three days.

Soda Creek Bridge Improvements
The team proposes structural reinforcements and improved bridge deck drainage to an improved outfall system.

County Road 314 Phase 2 Improvements
Improvements to County Road 314 between east Idaho Springs (Exit 241) and the recently completed County Road 314 improvements just south of Veterans Memorial Tunnels would be completed.

Active Traffic Management
Dynamic signage would inform drivers when the peak period shoulder lane is available for use to reduce congestion. This innovative design reduces safety risk and improves mobility.

Fiber Optic Upgrades
Fiber optic cables would be specifically designed and located to accommodate future emerging technologies for autonomous and connected vehicles, improving driver information and emergency response capabilities.

Dumont Port-of-Entry Interchange
The project would include merge area improvements to the Dumont interchange acceleration lane.

Project Facts

  • Cost: $70-$80 million
  • Location: On westbound I-70 between Empire Junction (mile point 230) and the Veterans Memorial Tunnels (MP 242)

Project Team

  • The project is following the I-70 Mountain Corridor CSS process. This process includes establishing a project leadership team, a technical team, and at least three issue task forces to discuss impacts to historic properties, wildlife and water resources.

    The CSS process includes establishing a context statement and core values of safety; mobility and accessibility; implementability; community; recreation; environment; engineering criteria and aesthetic guidance; sustainability; historic context; and decision-making.

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Westbound Peak-Period Shoulder Lane Context Statement

The I-70 Mountain corridor is a magnificent, scenic place in close proximity to the Denver Metro area. Human elements are woven through breathtaking natural features. The integration of these diverse elements has occurred over the course of time. The corridor is a recreational destination for the world, a route for interstate and local commerce and a unique place to live.

I-70 is also federally designated as a high-priority corridor, a significant part of the defense network, a major east/west continental corridor and a major economic corridor for Colorado. For many local communities along the corridor, I-70 is the lifeline, primary access and only connection to other communities.

Current I-70 roadway geometry is constrained with narrow shoulders and tight curves that impact safety, mobility, accessibility, and capacity for travelers and residents. In a manner that respects the unique environmental, historic, community and recreational resources in Clear Creek County, westbound improvements are needed to lessen delays caused by peak period volumes.


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