Transportation Solutions

Feature Friday: I-70 Fifth Street Interchange Improvements

Feature Friday: I-70 Fifth Street Interchange Improvements

CBB is a member of the team currently working on improvements at the Fifth Street and I-70 Interchange in St. Charles County, MO. The interchange provides access to many of the region’s attractions including Historic Main Street St. Charles, St. Charles Convention Center, and the Family Arena, as well as a host of local businesses, shops, restaurants, hotels, and employment centers. The project will improve access and traffic flow and stimulate economic development at this very busy interchange.

Nearly one-half of the traffic crossing the Blanchette Bridge enters on exits at I-70 at Fifth Street and First Capitol Drive. This area is one of the busiest segments of I-70 in Missouri, and motorists face confusing intersections, intensive lane changing, and short merging areas. While several adjacent roads have been upgraded in recent years, the Fifth Street Interchange has not. The I-70 Fifth Street Interchange Improvements Project will connect to recent improvements on Fifth Street, I-70, and First Capitol Drive.

The project will construct a Diverging Diamond Interchange at Fifth Street; add new ramps to Fairgrounds Road; and connect the two interchanges with one-way outer roads. I-70 will be widened to four lanes in each direction under the First Capitol Drive overpass in order to increase capacity and reduce weaving on I-70. The project will fill in gaps in the local sidewalk system by building new sidewalks along Fifth Street, Veterans Memorial Parkway, and Fairgrounds Road. New bike lanes will be added to the Fairgrounds Road overpass.

CBB participated in the development of initial conceptual layouts and completed the operational performance evaluations with HCM, SYNCHRO, SIDRA, and VISSIM traffic flow models. We conducted safety studies using Highway Safety Manual methodologies and were responsible for the project’s Access Justification Report (AJR). We assisted St. Charles County in completing the projects Congestion Mitigation and Air Quality (CMAQ) federal funding application, which is ultimately contributing $3,879,000 to the project’s construction. During the design phase we served as the chief designer for all signing, striping, lighting, traffic signals and Intelligent Transportation Systems (ITS). Construction is set to begin in 2016 with proposed project completion in early 2017.

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