The interchange carries more than 300,000 vehicles per day, and the high traffic volumes have become a problem due the tight footprint of the interchange. Preliminary concepts to redesign the Circle Interchange range from adding lanes and widening ramps to and from some of the expressways to an ambitious four-level interchange that would include building a tunnel under existing infrastructure and building ramps.

"AECOM is honoured to partner and share its expertise with the IDOT and the local community on this critical transportation-infrastructure project," said John M Dionisio, Aecom chairman and CEO. "The proposed project would drive mobility and environmental improvements for Chicago¹s residents and visitors."

IDOT aims to reach a final decision on a preferred alternative by next year and begin construction in 2014 or 2015 if money becomes available. Aecom has not revealed the value of the contract, however local news reports have stated that this is a USD 40M engineering analysis.