Relocated Illinois 3 Project

Welcome to the homepage for the Relocated Illinois 3 project. The Illinois Department of Transportation (IDOT) is studying a preferred alternative for approximately two miles of Illinois 3 in East St. Louis and Sauget. 

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What

Relocated Illinois 3 is a transportation study being conducted in accordance with the National Environmental Policy Act (NEPA), a federal act that ensures projects consider their impacts to natural, social, and built environments.

Where

The Relocated Illinois 3 study begins north of Riverpark Drive and ends to the south near Monsanto Drive on and around the existing Illinois 3. The project area is approximately two miles in length.

Why

• A four-lane highway connecting East St. Louis from Waterloo to Alton, and all the communities in between, is needed to improve regional mobility in the Metro East area. The Relocated Illinois 3 project aims to:
• Improve traffic operations and safety, enhancing regional and local mobility to better connect East St. Louis community members and visitors with opportunities in the Metro East region
• Improve access to existing and future Mississippi River bridge crossings and the riverfront
• Provide highway continuity along Illinois 3, connecting this corridor with other existing and future four-lane expressways in the region
• Support economic development along the Illinois 3 corridor in East. St. Louis

Funding

• The current stage of the project, Relocated Illinois 3 Preliminary Engineering and Environmental Study (Phase I) is funded. The other two stages of the project, final detailed design studies (Phase II) and construction implementation (Phase III), are also funded, as documented in IDOT’s 2025-30 Multi-Year Plan (MYP). 

Project Overview

IDOT is conducting preliminary engineering and environmental studies, referred to as Phase I design, for the improvement of Illinois 3 in St. Clair County.

The study area extends from Illinois 3 north of Riverpark Drive to Monsanto Drive in Sauget, covering approximately two miles. 

Purpose and Need

According to the 2001 Environmental Impact Statement (EIS), the relocation and upgrade of Illinois 3 is needed to:

·         Increase highway capacity and safety

·         Improve access and traffic distribution to Mississippi River crossings

·         Complete a four-lane highway between Waterloo and Alton

·         Support economic growth

·         Improve access to existing, planned, and potential riverfront development

Project History and Location

The original 2001 EIS study limits extended along existing Illinois 3 from Monsanto Avenue in Sauget (St. Clair County) to the McKinley Bridge approach in Venice (Madison County). Over the past 20 years, many segments have been studied, with some already constructed and others approaching construction.

The current study focuses on the segment from Riverpark Drive in East St. Louis to Monsanto Avenue in Sauget. This section reentered Phase I design due to incompatible railroad changes that arose after the 2001 EIS.

In 2001, preliminary geometrics included an at-grade railroad crossing between the MacArthur Bridge and the I-55 structure. Following policy changes, IDOT introduced new grade separations in 2011, including a bridge over Trendley Avenue. Additional railroad construction in 2015 led to further grade separations and refinements at the Illinois 3/I-55 ramp intersection.

These 2011 and 2015 changes were consistent with land use planning and continued to meet the original purpose and need. They were documented in official design change memorandums.

Since 2015, more railroad infrastructure has been added or modified. This current phase evaluates how those changes affect the 2015 design and proposes updates to align with current design standards.

Schedule

This project is currently in Phase I, Preliminary Engineering and Environmental Studies, with a preferred design alternative under development. Phase II, Final Design, is anticipated to begin in 2026. Construction will follow, with specific dates to be determined.

Project Timeline

• 2001: Environmental Impact Statement (EIS) record of decision and design approval
• 2011: Design changes due to new railroad grade crossings, including:
  • Grade separations at Cargill Service Track, Trendley Avenue, and TRRA South Wye
  • Addition of the Trendley Connector
  • Documented in a Design Change Memorandum
• 2015: Further design changes at 8^th and Poplar ramps, including:
  • Grade separations at TRRA and Union Pacific Railroad
  • Realigned Illinois 3/I-55 ramps intersection
  • Documented in a Design Change Memorandum
• 2022-Present: New study phase initiated due to incompatible railroad spur construction
  • Change conditions necessitate:
    • New rail line crossings
    • Relocated rail lines
    • Updated environmental and traffic studies
    • Stakeholder involvement
    • Coordination with the I-55/64 ramp replacement project
    • Progress toward final design

Materials and updates will be posted here as the study progresses.

Public involvement

Stakeholder input is critical to this study. Community members may join the Community Advisory Group (CAG), attend public meetings, and provide input at any point. Visit the Information Center page for public involvement opportunities and updates.

Subscribe for project updates here.

Current Materials

• Project timelines
• Study area map
• Event and meeting materials (to be published later)

Reports

2001 Environmental Impact Statement & Design Report

2011 Design Change Technical Memorandum

2015 Design Change Memorandum

Galleries 

What is the Relocated Illinois 3 study?

The Relocated Illinois 3 study is a preliminary engineering and environmental (Phase I) study being conducted under the National Environmental Policy Act (NEPA). This federal act that ensures transportation projects consider environmental and community impacts. 

Where is the study taking place? 

In East St. Louis and Sauget, Illinois, from Illinois 3 north of Riverpark Drive to south near Monsanto Drive. The project is approximately two miles long. 

Why is this study taking place? 

To address regional needs for safer roads, improved access to Mississippi River crossings, completion of a four-lane highway from Waterloo to Alton, and enhanced economic and riverfront development in East St. Louis. 

What does a Phase I study include? 

IDOT’s Phase I involves preliminary engineering and environmental assessments to identify a preferred design alternative. Components include:

• Data collection and stakeholder engagement
• Identification of transportation needs
• Development and evaluation of alternatives
• Selection and refinement of the preferred alternative.
• Approval of an environmental and engineering report

What happens after Phase I?

The project moves into Phase II: Final Design, which includes detailed plans, specifications, and cost estimates. Land acquisition also occurs during this phase if needed. Phase III involves construction. 

How is the project funded? 

Funding for all phases, including construction, is provided in IDOT’s 2025-30 Multi-Year Plan (MYP). 

What is NEPA?

NEPA is a federal act that mandates environmental considerations in federally funded project decisions. It ensures natural, social, and built environments are evaluated alongside cost and technical factors. 

How can I get involved? 

Stakeholders are encouraged to join the Community Advisory Group (CAG), attend public meetings, and share input. Visit the Information Center for details and sign up for email updates. 

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