This project included Phase I and II Preliminary Engineering and Design, by McClure Engineering, and Phase III Construction Engineering services, by Chastain & Associates, for a new full access interchange connecting Illinois Route 173 to the Northwest Tollway (I-90) in northeast Winnebago County, north of Rockford, Illinois.
Four new ramps involving a partial cloverleaf and half diamond were needed to make the connection between the two routes. The Northbound and Southbound bridges carrying I-90 over IL 173 were removed and replaced with longer, wider structures to facilitate the Open Road Tolling changes and the widened IL 173 pavement below.
Construction on IL 173 included widening 1.7 miles from a two-lane rural highway to a six-lane urban roadway with a raised two-lane wide concrete median. Four new signalized intersections were constructed to control the traffic entering and exiting the Tollway and local roads along IL 173. Additional items included street lighting, regional detention ponds, signing and pavement marking.
IL 173 was closed to through traffic during constuction, but both directions of I-90 had two lanes available for traffic at all times. Median crossovers were utilized on I-90 to maintain the required traffic flow during construction.