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 problems that have impacted this region for decades.

Construction Update

The new Veterans Memorial Parkway arch underneath the Cave Springs interchange is now open! This means outer road traffic will not have to stop at a signal at Cave Springs.

View weekly traffic impacts
cave springs interchange

Explore the I-70 Plan

Click or tap the yellow dots below to learn more about the changes happening throughout the project area.

project limits map

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 awarded to Best Value Proposer

Summer 2022
Construction begins.

Summer 2022
Lanes narrowed in both directions of Interstate 70 at the Cave Springs and Zumbehl interchanges

Summer 2022
Construction begins on new bridges at Zumbehl over I-70 and at Cave Springs over I-70 and Veterans Memorial Parkway

Fall 2022
Lanes narrowed and shifted on Cave Springs over I-70

Spring 2023
Traffic will be shifted to the new bridges at Zumbehl over I-70 and at Cave Springs over Veterans Memorial Parkway. Current Cave Springs and Zumbehl bridges will be demolished

Summer 2023
Construction begins on new North outer road between Fairgrounds and Route 94.

Summer 2023
Construction begins at Route 94

Summer 2024
Project will be complete.


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 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 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