Illiana Expressway Feasibility Study

Indiana Department of Transportation

Study identifies three possible corridors for Illiana Expressway.


To determine the overall viability of developing, financing, constructing, operating, maintaining, and placing into service a new Interstate quality highway to be known as the Illiana Expressway. The proposed expressway would be 25 to 30 miles in length, connecting I-57 in Illinois with I-65 in Indiana.

Project Overview/Challenge

The Illiana Expressway corridor has been a component of long-range plans for the bistate region since the early 1900s, first envisioned by Daniel Burnham as a vital link in the outer ring of highways encircling the Chicago region. Formerly known as the South Suburban Expressway, the corridor has shifted southward over the years as the Chicago metropolitan area has expanded geographically and available right-of-way has become more limited. Traffic volumes have increased each year on competing routes, resulting in congestion and delay that impact not only passenger travel, but also result in significant economic impacts to industries that depend on the ability to move freight within and through the region.

Our Approach

The Cambridge Systematics approach to performing the Illiana Expressway Feasibility Study included the following steps:

  • Define the study area;
  • Implement a Public Outreach program;
  • Establish project purpose and need;
  • Perform environmental overview;
  • Identify and develop conceptual engineering and cost estimates for three alternative alignment corridors;
  • Develop “Illiana” travel demand model for forecasting travel volumes and toll sensitivity on alternative alignments;
  • Identify and compare project benefits, opportunities, and impacts;
  • Study identifies three possible corridors for Illiana Expressway;
  • Perform Traffic and Revenue Analysis to estimate debt capacity by alignment; and
  • Identify alternative financing approaches.

Project Results

  • Projected volumes up to 43,000 vehicles per day.
  • Conceptual cost estimates ranging from $600M to $1B, based on alignment and cross section scenario.
  • Debt capacity based on toll revenue up to 56 percent of project cost.
  • Benefits and opportunities include: congestion relief, safety enhancements, regional and national economic benefits, enhanced freight mobility, environmental benefits, and transit linkages.
  • Potential impacts to the environment include: displaced structures and farmland, parklands and managed lands, historic and archaeological areas, hazardous material sites, sensitive habitats, wetlands, and floodplains.