Wight provided Phase III engineering services and structural analysis for the I-55/I-355 Interchange. The project included roadway, ramps, drainage, earthwork, and 1,400 feet of retaining walls.

In addition to the roadway, the project included the construction of five major bridges: two mainline structures, which were each over 350-feet long; an integral abutment mainline bridge that is over 100-feet long; and two curved steel girder flyover structures - one over 1,900-feet long and the other over 2,600-feet long.