Illinois Route 3 Improvements

IDOT, Region 5, District 8

Horner & Shifrin completed Phase I & II services for IDOT, including the design of the first roundabout in Monroe County.


Illinois Route 3 in Waterloo is the major thoroughfare for traffic commuting to St. Louis from southwestern Illinois in addition to serving the many agricultural facilities in the area. Traffic had grown steadily since the 1990s and congestion was becoming an increasing issue leading to the need to expand the capacity of roadway.

Horner & Shifrin was contracted by IDOT to carry out Phase I/II services for this project. Tasks during the Phase I preliminary engineering and environmental study phase, which consisted of preparing a project report that documented the alternative alignment selection process and environmental and engineering restraints associated with the study area. Tasks also included conducting intersection design studies, a noise analysis, a location drainage study, a crash analysis, and a traffic management analysis. A key part of the study phase was the use of the public involvement Context Sensitive Solutions (CSS) process which included a Community Advisory Group, public meetings, one-on-one stakeholder meetings, and multiple newsletters. As a result of the CSS process, a safety issue at Vandebrook Drive was discovered just outside the original limits of the project. The result was relocating Vandebrook Drive to the existing traffic signal at the south end of the project.

Following the approval of the project report, the Phase II contract plans phase consisted of preparing the plans, specifications, and estimates for the construction. This phase involved the design a four-mile-long, 10-foot-wide shared use path that included a box culvert underpass to address the Complete Streets policy and the design of the first roundabout in Monroe County. Because this route is such a lifeline for the area, schedule adherence was imperative, resulting in Horner& Shifrin completing this phase of the project in a remarkable timeframe of five months. Construction was completed in June 2017.

2013 ACEC-IL Engineering Excellence Merit Award Winner.



Site Size

4 miles


Waterloo, Illinois

Year Completed


Innovation. Agility.
Reliability. Horner & Shifrin.