I-70 Cave Springs to Fairgrounds Design-Build
Table of Contents
The I-70 Cave Springs to Fairgrounds project is a Design-Build project that will make improvements to increase safety, make the interchanges smoother to move through and support local access.
- Maximize improvements within the program budget of $62 million.
- Improve safety and efficiency of the transportation network while supporting
connectivity for the local community.
- Provide a durable and maintainable transportation infrastructure allowing for future
- Minimize impacts to the traveling public during construction while safely delivering
project by November 1, 2023.
- Deliver the project using a diverse workforce.
Infrastructure upgrades are needed because the population of St. Charles County is nearly three times what it was in 1980 when these interchanges were built.
The Cave Springs and Zumbehl interchanges often experience traffic jams making it tough for traffic to flow through the area. During the morning rush, vehicles crossing the interchange average a speed of 18 mph on Zumbehl Road and 7 mph on Cave Springs.
These delays cause traffic to back up onto I-70, creating a serious risk to safety. The interchanges have a higher than average crash rate. Between 2013 and 2017 the average crash rate in the area was more than 40% above the statewide average rate.
An interstate system includes outer roads, interchanges and the interstate. In this area, a section of the north outer road is missing, and Veterans Memorial Pkwy is disconnected by a large island at Cave Springs. This design makes it difficult to navigate the area.
The need for this project came from the I-70 Planning and Environmental Linkage Study (I-70 PEL) completed in 2018. The PEL identified the following major strategies to address the issues in the area:
- Upgrade infrastructure to better accommodate freight
- Improve local/parallel road systems
- Reduce/eliminate conflict points at interchanges
- Improve interchange operations
- Add/improve bicycle & pedestrian facilities
More information about the PEL, including the full report can be found here. The I-70 Cave Springs to Fairgrounds Project falls in Sections 2 and 3.
Possible Solutions to Fix Problems
Diverging Diamond Interchanges (DDI)
- Handles heavy left turn movements efficiently
- Reduces conflict points to improve safety
- Uses current lanes without additional signals
Single-Point Urban Interchange (SPUI)
- Fits within existing Right of Way
- Reduces signals to improve traffic flow
- Accommodates large trucks more easily
Flashing Yellow Left Turn Arrows
- Reduces crashes
- Increases opportunities to turn left
- Handles more traffic safely
- Moves traffic efficiently without signals
- Reduces severity of crashes
- Slows vehicles, improving safety
One-Way Outer Road
- Improves safety by reducing congestion
- Reduces travel time in congested areas
- Moves traffic from interstate to outer roads
Two-Way Outer Roads
- Allows for conventional traffic movement
- Reduces travel distance
- Decreases traffic on the outer roads
Cave Springs and Zumbehl Interchange Study completed by City of St. Charles.
I-70 Planning and Environmental Linkages (PEL) Study from Wentzville to Mississippi River completed.
I-70 from Cave Springs to Fairgrounds identified as regional priority and MoDOT funds this project in the 2020-2024 Statewide Transportation Improvement Program (STIP).
Project designated as Design-Build and project team formed.
MoDOT delays project to engage with the public.
Project awarded to the Best Value Proposer.
Construction will begin.
Project will be complete.
MoDOT & Federal Funding
St. Charles County Cost Share
Total: $62 million
Disadvantaged Business Enterprise (DBE) Goals
14% for construction activities
20% for professional service activities
Federal Workforce Diversity Goals