The I-70 mountain corridor is the only east-west interstate and primary access route from Denver to the mountains. The segment of the corridor that runs from Empire Junction to the Twin Tunnels at Idaho Springs is one of the most heavily populated areas of Clear Creek County—and one of the narrowest sections of the corridor. To combat severe traffic delays during peak periods for eastbound traffic, CDOT created an express lane on existing right-of-way by allowing traffic to use the shoulder only during peak periods. The shoulder lane is open only to drivers willing to pay a toll (which is determined through Active Traffic Management and Dynamic Pricing). The project also included the design and reconstruction of two bridges, a roundabout, bike and pedestrian facility improvements, and retaining walls to limit impacts to fishing and rafting along Clear Creek. Since completion, the project has reduced the impacts of heavy traffic on businesses and residences in the mountain communities. The new lane, which cost $72 million, captured 8 percent of traffic in its first summer season and cut travel time for drivers by 40 percent in the general purpose lanes.