Resources

The study limits include Illinois 173 beginning 0.4 miles west of the Village of Poplar Grove and extending east to Boone-McHenry County Line Road, over 8 miles.

Project Location Map

The phase I pre-final geometry plans are based on the analyses for the recommended design improvements. These plans represent the recommended design improvements at approximately 90% complete. These plans are being used for the following tasks.

• Public involvement
• Set preliminary construction limits
• Set preliminary right-of-way limits and determine any easement requirements
• Obtain approval of all design exceptions (A design exception is a deviation from prevailing design standards to achieve a balance of project needs and community values)
• Conduct preliminary utility review to determine if any utility adjustments are necessary
• Prepare the drainage report
• Prepare the environmental documentation

Adjustment to the phase I pre-final geometry plans may be made to accommodate the results of the above analysis, public involvement, and other tasks.

Note that phase I (the project study) pre-final geometry plans are for planning and not construction. During phase II (design) additional details are added to the phase I pre-final geometry plans to create the phase II construction plans.

Plan and Profile Sheets

The plan and profile sheets are a type of engineering drawing that combines a plan view and a profile view of the road. The plan view is a map of the road. The profile view is a plot of the elevations of roadway features, such as centerline and ditches, where the horizontal axis (x axis) is based on feet along the centerline of the road and the vertical axis (y-axis) is the elevation.

• Plan and Profile Sheets 
  • Illinois 173 through the Rural 1 Section
  • Illinois 173 through the Poplar Grove Section
  • Illinois 173 through the Rural 2 Section
  • Illinois 173 through the Capron Section
  • Illinois 173 through the Rural 3 Section
    
    
  • Crossroads through the Rural 1 Section
  • Crossroads through the Poplar Grove Section
  • Crossroads through the Rural 2 Section
  • Crossroads through the Capron Section
  • Crossroads through the Rural 3 Section

Typical Section Sheets

Typical sections are detailed cross section depictions of the highway's principal elements that are standard between specified station limits, feet along the road. These sections are the basis for construction details and information shown on the various plan sheets throughout the improvement. Typical sections show typical conditions only. Non-standard conditions that prevail for short distances are not shown.

• Existing Typical Sections Sheets Links 
  • Illinois 173 through the Rural Sections
  • Illinois 173 through the Poplar Grove Section
  • Illinois 173 through the Capron Section

• • Crossroads in the Rural Sections
  • Crossroads in the Poplar Grove Section
  • Crossroads in the Capron Section

• Proposed Typical Sections Sheets Links 
  • Illinois 173 through the Rural Sections
  • Illinois 173 through the Poplar Grove Section
  • Illinois 173 through the Capron Section
    
    
  • Crossroads in the Rural Sections
  • Crossroads in the Poplar Grove Section
  • Crossroads in the Capron Section

IDOT will be conducting a Public Informational Open House to encourage input from the public regarding the proposed improvements to IL-173 from 0.4 Miles W. of Village of Poplar Grove to Boone-McHenry County Line Road.

Date and Location

Wednesday, May 21, 2025

1-6 p.m.

Capron Lions Community Building

305 E. North St., Capron, IL 61012

Check the Frequently Ask Questions (FAQ) page.

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