Creating an easier, safer, and smoother I-70 Interchange System.

The I-70 Cave Springs to Fairgrounds project is a Design-Build project that will make improvements to address the connectivity, safety and congestion issues that have impacted this region for decades.


The outer roads in the area are disconnected which sends local traffic onto the interstate or other local streets. Improving connectivity in the area would make travel more natural, reduce congestion and use the available space wisely. This would create an ease of access for residential and commercial properties.


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.


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.

Project Map showing the project limits on I-70

Project Goals


Improve connectivity for the local community while maximizing safety and efficiency of the transportation network within the program budget of $62 million. a chart depecting the budget


Provide a durable and maintainable transportation infrastructure allowing for future expansion.


Minimize impacts to the traveling public during construction while safely delivering the project by June 28, 2024.


Deliver the project using a diverse workforce.

Disadvantaged Business Enterprise Goals (DBE)
  • 14% for Construction Activities
  • 20% for Professional Service Activities
Federal Workforce Diversity Goals
  • 14.7% Minority
  • 6.9% Female

Understanding the Issues


The I-70 inner and outer road system is not complete, making it difficult to navigate. The map below shows the two main areas of discontinuity.

Map showing Cave Springs and Convention center locations


Crashes occurring from 2015-2019 within the Project Corridor are shown in the graphic below. The highest density of crashes occur in and around the major I-70 interchanges.

Map showing crash densities


Traffic congestion is typically the highest during AM and PM rush hours. The maps below show the predicted congestion in 2045 if no changes are made to the I-70 Interchange System.

Map showing traffic congestion hotspots

Project Schedule

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 a regional priority.

MoDOT funds the project in the 2020-2024 Statewide Transportation Improvement Program (STIP).

Project designated as Design-Build and project team formed.

Winter 2020 - Spring 2021
Public engagement period.

Early 2022
Project expected to be awarded to the Best Value Proposer.

Spring 2022
Construction anticipated to begin.

Summer 2024
Project will be complete.