Mack Road Bridge Reconstruction and Multi-Use Path

Phase II/Final Engineering

Estimated Construction: 2024 or 2025

Project Overview: In December 2015, the City was awarded federal Surface Transportation Program (STP) funding that will cover 75% of construction costs and construction engineering to add a multi-use path along the south or north sides of Mack Road, just east of Route 59. In May 2018, the City was awarded Surface Transportation Bridge Program (STP-Br) funding for the replacement of the bridge.  The proposed improvements include pedestrian signal modifications at the intersection of Route 59 and Mack Road, a 10-foot wide asphalt path on the north side of Mack Road, a new Mack Road Bridge over the West Branch of the DuPage River, and a connection to the existing trail system in the Blackwell Forest Preserve.  The Forest Preserve District is a partner in this project. 

The proposed improvements include construction in the floodplain, however the raised roadway profile will reduce flooding of Mack Road and appropriate drainage systems are proposed. Compensatory storage will be provided to offset the fill in the floodplain.  Construction of the bridge and multi-use path will require easements and/or right-of-way (ROW) acquisition due to the limited existing ROW. Easements and/or ROW acquisition will range from approximately 8 to 25 feet north of the existing ROW. Temporary easements will also be required beyond these limits during construction.

The proposed Mack Road improvements will affect the Forest Preserve property south of Mack Road and will connect to the existing trail in Blackwell Forest Preserve. As a publicly owned Forest Preserve District of DuPage County property it is subject to protection under Section 4(f) of the U.S. Department of Transportation Act of 1966. For the Mack Road project, the City of Warrenville intends to seek a Section 4(f) “de minimis” impact finding from the Federal Highway Administration based on a determination that the project will not adversely affect the features, attributes, or activities that qualify the property for protection under Section (f). The multi-use path is proposed on the north side of Mack Road to minimize impacts to the high-quality area of the Forest Preserve. This is a federally-funded project, and the public Information Meeting is being held in compliance with National Environmental Policy Act (NEPA) requirements and the Illinois Department of Transportation’s public involvement policy.

Consultant Selection: Engineering Resource Associates, Inc.

Schedule:  Final Engineering is ongoing. Construction bid letting is anticipated to be late 2023 or 2024.  Construction will begin in late 2024 or 2025

Current Steps: 

  • Final Engineering
  • Easement / ROW Negotiations
  • Construction Bid Document Preparation

Next Steps: 

  • Construction

Completed Steps:

Frequently Asked Questions:

When will this project be constructed?

The anticipated bid opening through IDOT is scheduled for November 2023 or November 2024.  Construction is anticipated to begin in 2024 or 2025 and last approximately 9 months to 1 year.

Why is the multi-use path proposed on the north side and not the south side?

The north side was the preferred alternative recommended by City staff, Forest Preserve District, Winfield Township, City of Warrenville Bicycle and Pedestrian Commission, and approved by the Warrenville City Council.  The north side:

  1. Avoids a un-signalized mid-block crossing. The Average Daily Traffic (ADT) from IDOT's traffic counts on Mack Road totaled about 4,000 vehicles per day in 2016 and 2,200 vehicles per day in 2020.  Design ADT was approved at 2,916 vehicles per day (includes adjustment factor due to COVID in 2020). Between the hours of 7 am - 5 pm, that is about 3.5 cars per minute traveling on Mack Road.  Furthermore, IDOT recommends avoiding mid-block crossings when possible.
  2. Avoids an expensive reconstruction/reconfiguration of the Forest Preserve dog park and boat launch.  This reconstruction would not be applicable for STP grant funding.
  3. Avoids the Class IV sensitive Forest Preserve property that contains high quality natural area and woodlands.
  4. Avoids a Section 4(f) review which applies to federally funded projects.  Section 4(f) requires that there is no feasible and prudent alternative that avoids the Section 4(f) properties and that the project includes all possible planning to minimize harm to the Section 4(f) properties.  For this project, the Section 4(f) property is the Forest Preserve District property on the south side of Mack Road.

What analysis was done to recommend the north side as a preferred alternative?

The City hired Engineering Resource Associates, Inc. (ERA) to perform an alternatives analysis.  Three alternatives: path on north side, path on south side, or on street bike lanes were analyzed.  The preferred alternative of a path on the north side was presented to City Council in May 2017 and approved.  This option was the most cost-effective and safer alternative. The first public information meeting was held on October 11, 2017.   See powerpoint and alternatives analysis from this meeting.

See summary of "Public Comments and Staff Responses" document for other questions asked during Public Meeting.