Services Provided
About the Project
St. Charles, Missouri
CBB is a member of the team that completed the design studies and plans for improvements at the Fifth Street/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 has improved access and traffic flow and stimulated 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. Prior to this project, motorists faced confusing intersections, intensive lane changing, and short merging areas. The I-70 Fifth Street Interchange Improvements Project corrected these issues and connected to other recent improvements on Fifth Street, I-70, and First Capitol Drive.
The project constructed a Diverging Diamond Interchange at Fifth Street; added new ramps to Fairgrounds Road; and connected the two interchanges with one-way outer roads. I-70 was widened to four lanes in each direction under the First Capitol Drive overpass to increase capacity and reduce weaving on I-70. The project filled 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).
CBB assisted St. Charles County in completing the project’s Congestion Mitigation and Air Quality (CMAQ) federal funding application, which contributed $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).
