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Air Mobility Drive Extension Study


Thank you for visiting the Air Mobility Drive Extension Study website. The Illinois Department of Transportation is conducting a preliminary engineering and environmental study for the proposed extension of Air Mobility Drive (Illinois 158) from Illinois 161 to Illinois 158/77 in St. Clair County.

Air Mobility Drive is a four-lane divided highway that provides access to Scott Air Force Base, MetroLink rail line and Interstate 64. When Air Mobility Drive was constructed, the original intent was to continue the four-lane highway section from Illinois 161 to Illinois 158/177. Right –of way for that extension was purchased for that work in the 1970s, but construction was not completed. The intent of this project is to construct the remainder of the roadway to the south for which the right of way was purchased. Please see the map under the Project Location tab on the website.

Questions about the project can be directed to the IDOT Project Manager, Annie Prothro, at Annie.Prothro@illinois.gov. Or, you can mail:

Illinois Department of Transportation
Attn: Annie Prothro
1102 Eastport Plaza Drive
Collinsville, IL 62234


Project Problem Statement

A Project Problem Statement is a concise narrative, prepared at the start of a project to define the problem to be solved. The problem statement developed by the IDOT study team for this project is as follows:

Air Mobility Drive Extension PROBLEM STATEMENT

“The transportation issues for the adjacent roadways of the Illinois 158 extension are related to the projected increase in traffic, which will result in reduced mobility on those routes.

A Need for Improvement

With traffic projected to increase substantially on Green Mount Road, extending Air Mobility Drive will help improve mobility to the surrounding road systems.

  • Traffic in the study area is expected to grow 20% or more over a 20-year period.
  • If no improvements are made, Green Mount Road will reach its capacity
  • The planned widening of Green Mount Road (by the county and IDOT) to five lanes will enable it to handle the increased traffic from planned development but will not relieve traffic along Air Mobility Drive.
  • Radio Range Road currently serves as a ‘shortcut’ for traffic to bypass the delays of the traffic signals to the west on Illinois 161 and Green Mount Road to the south, for which it wasn’t designed.


Proposed highway improvements are typically processed in three phases.  In Phase I (preliminary engineering phase), proposed geometry, environmental concerns, and right-of-way requirements are defined.  This phase generally takes an estimated 24 months to complete.  During Phase II, contract plans are prepared, and the necessary right-of-way is acquired.  This phase generally takes an estimated 12-24 months to complete.  Phase III represents the actual construction of the improvement.  This phase generally takes an estimated 18-24 months to complete. This project is currently in Phase I.

Public Involvement

Context Sensitive Solutions will be utilized for the public involvement for this project. The formal policy may be reviewed online here.

Context Sensitive Solutions

An inclusive, responsive public involvement program is an essential part of this project.  The public involvement program is being implemented using the principles of Context Sensitive Solutions and follows the policies and procedures for CSS as developed by IDOT. CSS is a collaborative approach that involves all stakeholders to develop a transportation facility that fits into its surroundings and preserves scenic, aesthetic, historic and environmental resources while maintaining safety and mobility.  

Public Meetings

IDOT is currently inviting the public to comment on the proposed improvement for the extension of Air Mobility Drive (Illinois 158) from Illinois 161 to Illinois 158/177. On Thursday, Oct. 21, IDOT held an in-person public informational meeting at Scott Elementary School at Scott Air Force Base in St. Clair County.

For those who were unable to attend the meeting in person, listed below are copies of all the exhibits made available for viewing and comment through this website.

The purpose of the meeting is to share the proposed improvement with the community and allow the project team to receive comments and answer questions from the community. 

The public is encouraged to participate in the Virtual Public Meeting to:

  • Learn about the purpose, need for the improvement, and the planning process
  • Review study exhibits and materials
  • Share ideas, ask questions, and provide feedback

Location Map

Project Purpose


Project Plan

Traffic Info

Crash History

Get Involved

If you have questions about the public involvement for this project, please contact the IDOT Project Manager, Annie Prothro, at Annie.Prothro@illinois.gov

IDOT is currently at the early stages of Phase I for this project. As we make changes, this website will be updated accordingly.

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