I-70 Westbound Peak Period Shoulder Lane

One major component of ongoing I-70 mountain corridor work is the addition of a 12-mile tolled westbound peak period shoulder lane (aka Express Lane) between the Veterans Memorial Tunnels (mile point 243), and the US Highway 40 and I-70 interchange (exit 232). This lane will be similar to the I-70 Mountain Express Lane already in place for eastbound travelers in that it will offer drivers a choice during peak travel periods and improve safety, connectivity and mobility on the I-70 mountain corridor.

On July 15, 2019, CDOT and prime contractor, Graham U.S., began the 18-month construction project to add this westbound Express Lane. Click on the construction link to the left for more details.

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The National Environmental Policy Act process and study were completed in November 2018, enabling construction to move forward in delivering these improvements:

The general purpose lanes and shoulder of westbound I-70 are resurfaced and widened in select locations on the existing alignment to accommodate a lane on the shoulder for use during peak travel periods. Drainage enhancements include a storm system for minor and major storm events and water quality facilities. At State Highway 103, I-70 is slightly realigned to enhance safety and improve drainage.

The two general purpose lanes remain open and free to all travelers at all times. During non-peak travel periods, the PPSL is closed to traffic and functions as an extra-wide shoulder. Similar to the eastbound I-70 Mountain Express Lane, the westbound PPSL uses transponders and license plate tolling. Pricing is 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 coincide with peak travel periods on weekends and holidays.

A total of seven new safety pull outs are built – five along westbound I-70 and two along eastbound I-70. One existing safety pull out on eastbound I-70 is improved. The intention of these is to provide a space for vehicles to use if they experience a breakdown and for law enforcement to use.

Ramp improvements address sight distance problems. The pedestrian sidewalk is improved by adding lighting and a decorative paving buffer adjacent to the existing sidewalk on the CO 103 bridge over I-70. This sidewalk connects to a new sidewalk buffered from 13th Avenue between the interchange ramp and Idaho Street in Idaho Springs.

Rockfall mitigation measures are added at five locations to reduce the chance of 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 rockfalls; in 2014, I-70 was closed in both directions just west of Idaho Springs for three days.

Dynamic signage informs drivers when the PPSL is available for use to reduce congestion. This innovative design improves mobility.

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

Merging area improvements to the Dumont interchange acceleration lane include restriping of I-70 to reduce merging conflicts between truck traffic and the general purpose lane traffic.

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