IL Route 31 Algonquin Western Bypass

McHenry County Division of Transportation

This project consisted of preliminary engineering for a four mile segment of IL Route 31 from Edgewood Drive to Rakow Road, including the Western Bypass of the Village of Algonquin in McHenry County.  The initial feasibility study phase of this project included elements of the Context Sensitive Solutions (CSS) process.  A Transportation Advisory Committee, which consisted of local agency officials as well as environmental and civic groups, was developed to direct the course of the study. Numerous small group meetings were held with local interest groups, business owners, and area residents.  As part of this process, a dozen alternatives were developed, analyzed, and a consensus was reached selecting the Western Bypass as the Preferred Alternative.  As part of the detailed analysis of the Preferred Alternative, seven interchange designs were investigated, including a Single Point Urban Diamond Interchange as well as a Compressed Diamond Interchange.  An Environmental Assessment and Location Design Report were prepared.

The proposed Bypass facility passes through Towne Park, which is a significant community facility within the Village of Algonquin.  The Bypass also skirts the locally significant historic downtown district of the Village. In addition, the proposed alignment of the Bypass required the acquisition of approximately 1/4 mile of the McHenry County Conservation District’s Prairie Trail.  These impacts required extensive coordination with the McHenry County Conservation District, the Village of Algonquin, and the Illinois Historic Preservation Agency.  An individual Section 4(f) Evaluation was prepared for impacts to Towne Park and the Prairie Trail.

In addition, the Illinois Natural History Survey Identified the presence of a State-listed threatened and a State-listed endangered plant species within the study limits. The proposed improvement was modified to minimize and/or avoid impacts to these species.  A Threatened and Endangered Species Avoidance Plan was developed for this project.


Federal, State, County

Scope of Services

  • Environmental Assessment & Design Studies
  • Location Design Report
  • Stakeholder Involvement / CSS Process
  • Highway Noise Analysis
  • Air Quality Analysis
  • Location Drainage Studies
  • Intersection/Interchange Design Studies
  • Interagency Coordination
  • Hydraulic Studies
  • Section 4(f) Statement
  • Roadway and Highway Design
  • Drainage Design
  • Traffic Signal and Signal System Design
  • Preparation of Contract Plans, Specifications & Estimates
  • Lighting Design
  • Bikeway and Pedestrian Facility Design