Agencies
Services
Overview and Scope
The Illinois Department of Transportation (IDOT) is conducting a Phase I Engineering study of I-270 from Riverview Drive in St. Louis, Missouri to Illinois Route 157 in Madison County, Illinois. This study, referred to as the Illinois I-270 Preliminary Engineering Study, will investigate how to:
- address traffic growth,
- decrease congestion, and
- improve safety along the route.
The study will develop the engineering and environmental analysis required by Federal Law, the National Environmental Protection Act (NEPA). This project will be processed as a Federally Approved Categorical Exclusion.
This study will also closely examine the reconstruction of the I-270 and IL Route 111 interchange, which will be funded and constructed as a separate project.
An inclusive, responsive public involvement program is an essential part of this project. The public involvement program is being implemented using the Context Sensitive Solutions (CSS) process as developed by IDOT. This process helps ensure that any recommended transportation improvements will enhance the quality of life for those who have a stake in the system. This collaborative approach also preserves scenic, aesthetic, historic, and environmental resources while maintaining safety and mobility. For more information on CSS please visit the Get Involved page of this website.
Background
The most northern connection between St. Louis, Missouri and Madison County, Illinois is I-270. This portion of the interstate, from IL 157 to the Missouri state line, is largely a four-lane highway which travels over several railroads, has interchanges with several state routes and is adjacent to urban development, distribution and logistics parks, residential subdivisions, and farmland. This portion of I-270 carries traffic through or near St. Louis, Missouri; and Granite City, Mitchell, Pontoon Beach, and Glen Carbon, IL.
As a direct route to and from St. Louis County into Illinois, I-270 is a common corridor for many motorists who work, live, and/or go to school on opposite sides of the Mississippi River. With population density increasing in St. Louis County and nationwide freight movement expanding through the area, the four-lane highway has seen significant increases in traffic volume and the number of crashes. Current Average Annual Daily Traffic on I-270 is nearly 57,000 vehicles. IDOT will evaluate these issues and other concerns identified during the Illinois I-270 Preliminary Engineering Study.
