Macon County Beltway feasibility study, design report and environmental assessment

Project Summary

The Macon County Highway Department selected Hanson to conduct a study of the feasibility of constructing a bypass around Decatur and of several alternatives to the beltway. One of these alternatives was a no-build option.  Based on the results of the study, which identified the benefits, costs and impacts associated with each option, Hanson recommended a single alternative for further study.

The study team reviewed possible corridors and facility types to determine the impact on congestion problems; assess modal opportunities; establish the typical section’s right-of-way needs; and access control requirements of a future beltway.

This review included identifying logical termini and considering potential interchange and intersection locations, drainage impacts, grade separations, side-road realignments and other potential impacts.  Hanson also considered how the proposed alternatives would interact with the Decatur Airport Layout Plan and existing and proposed industrial areas.

Throughout this feasibility study, Hanson focused on the following tasks:

  • Identifying potential environmental concerns or sensitive resources to be taken into account in planning for a future transportation facility,
  • Developing trip generation and distribution rates for the region using the existing travel simulation model, nationally published averages and any existing information concerning travel patterns,
  • Forecasting the trip generation and interaction for each land-use scenario,
  • Estimating the impact of the proposed roadway on other major corridors in or near the study area and compiling the information in a technical memorandum,
  • Evaluating market demand in the study area, identifying existing land-use and development patterns, and assessing public policy influencing land use to determine the general economic impacts in the study area, and
  • Facilitating three public informational meetings and developing four project newsletters as part of the study process. 

After the feasibility study was finished, Hanson was selected to prepare an Illinois Department of Transportation (IDOT) Phase 1 Design Report and to conduct an environmental assessment of the alternatives identified in the feasibility study.  This process involved the following:

  • Refining the comparison of the alternatives identified in the feasibility study,
  • Preparing a purpose and need statement for the Federal Highway Administration’s review as part of the National Environmental Policy Act’s (NEPA) 404 process,
  • Identifying a preferred alternative and presenting it to the NEPA 404 agencies for approval,
  • Completing hydraulic studies of stream crossings,
  • Preparing bridge-type studies of stream, rail and highway crossings,
  • Preparing an interchange-type study,
  • Preparing interchange and intersection design studies for approval by IDOT’s district geometric engineer,
  • Reviewing the environmental impacts of the alternative and the preferred alternative,
  • Submitting an Environmental Survey Request form for clearance on threatened and endangered species and cultural and wetland impacts,
  • Submitting clearance to the Illinois Department of Agriculture for the identified impact to farmland,
  • Coordinating Section 4(f) and 6(f) impacts with the Macon County Highway Department, Illinois Department of Natural Resources, and the National Park Service, and
  • Identifying and negotiating land acquisition for the client to mitigate the Section 4(f) and 6(f) impacts.