Data-Driven Decisions
for Capacity Projects

The Illinois Department of Transportation is in the process of developing the Data-Driven Decisions tool, allowing us to improve how we determine investment decisions for capacity projects throughout the State. The concept of Data-Driven Decisions for project selection is used throughout the nation and encouraged by the U.S Department of Transportation. The Department evaluated 34 projects for inclusion in the State Fiscal Year 2023-2028 Highway Improvement Program. A cover memo is provided explanation of the selections.

Transportation System Background

Illinois is the 5 th largest economy in the nation, by GDP, and that prosperity would not be possible without our vast transportation network. For more information please visit our network overview page .

Key Transportation Metrics

  • 2185 Interstate Miles (3rd in the nation)
  • 145,976 Miles of Public Roads
  • 306,524 Lane Miles in Illinois
  • 26,809 Bridges (3rd in the nation)
  • 7,119 Miles of Rail
  • 7 Class I Railroads
  • 1,118 Miles of Navigable Waterways
  • 17 Major Airport Facilities
  • 54 Transit Systems Across Illinois

Transportation Funding

Funding for IDOT projects comes from multiple sources including:

  • Rebuild Illinois
  • Motor Fuel Tax (MFT)
  • Portion of the Motor Vehicle Registration (MVR)
  • Federal Funding

The majority of these funds are allocated toward system maintenance projects. Remaining funds can then be allocated toward expansion, capacity, or other types of projects. IDOT strives to use all available funding as efficiently as possible, keeping our vital transportation network running.

Why is IDOT Developing the Tool?

Transportation funding is limited and a majority of IDOT’s funds are allocated toward system maintenance projects. To increase transparency and select projects in an equitable manner IDOT began developing this Data-Driven Decision tool.

The Data-Driven Decisions Tool will enhance transparency in the project selection process and demonstrate why IDOT selects one project over another. Goals and selection criteria will allow IDOT to identify projects which provide the greatest benefit for the state, its residents, and supports the department's mission.

How is IDOT Developing the Tool

IDOT is developing the tool with guidance from the following:

  • Existing planning documents, including IDOT’s Long-Range Transportation Plan
  • Federal guidance urging the use of performance based project selection set forth by Moving Ahead for Progress in the 21st Century Act (MAP-21)
  • Counsel from state and national experts including transportation stakeholders and the Federal Highway Administration
  • Input from the local and regional leaders, and the public
  • Accepted industry metrics

What is the Tool

Based on the work done thus far, IDOT has developed a process which will select projects based on five goal areas and eleven selection criteria. These proposed goals and criteria will help IDOT make investment decisions on capacity projects in a transparent and equitable manner.

Goal: Traffic Operations/ Congestion View 3 criteria

  • Criteria: Annual Average Daily Traffic (AADT)

    A measure of change of the mean traffic volume across all days for a year for a given location along a road.

  • Criteria: Change in Annual Vehicle Miles Traveled (AVMT)

    A measure of the amount of vehicular travel in a geographic region over a given period of time.

  • Criteria: Travel Time Index

    The ratio of the travel time during the peak period to the time required to make the same trip at free-flow speeds.

Goal: Safety View 1 criteria

  • Criteria: Crash Frequency

    A measure of the number of crashes occurring within a specific jurisdiction, on a roadway segment, or at an intersection.

Goal: Economic Development View 3 criteria

  • Criteria: National Highway Freight Network

    Is the project on the National Highway Freight Network as defined by the Federal Highway Administration and the FAST Act?

  • Criteria: Major Development

    Does the project support access to a major development?

  • Criteria: Intermodal Accessibility

    Is there an intermodal facility within 3-miles of the project?

Goal: Environmental Impacts/ Livability View 5 criteria

  • Criteria: Environmental Justice

    Consideration of whether the project is located in an area identified as minority population, low income, or both based on the measures identified by the Illinois Environmental Protection Agency.

  • Criteria: Level of Environmental Impact Analysis Required

    How much will this project potentially affect the environment?

    • Categorical Exclusion (CE)
    • Environmental Assessment (EA)/Finding of No Significant Impacts (FONSI)
    • Environmental Impact Statement (EIS)
  • Criteria: Resiliency

    Will this project enhance the safety of travelers by better withstanding natural disasters, such as flooding.

Goal: Regional Rating View 1 criteria

  • Criteria: Subjective portion allowing local and regional input, to consider factors which may not be shown in the data
    • Allows for input from IDOT district staff on projects
    • IDOT district staff work directly with local municipalities, counties and Metropolitan Planning Organizations.

Goal: Coming soon View 2 criteria

  • Criteria: Equity

    How much will this project impact equity?

    • Access to transit
    • Housing and transportation cost index
    • Emissions
    • Other
  • Criteria: Emissions

    Will this project help reduce vehicle emissions and improve overall air quality?

For a comprehensive explanation of the tool, methodology, and calculations, the Department has developed a Methodology Document.

Thank You For Your Input

The Department hosted a webinar on September 29, 2021 on the proposed criteria. A recording of the webinar can be found by clicking here.

A copy of the presentation is available here.

A short survey on the Data Driven Decisions Tool closed on October 27, 2021. A summary of the results is available here.

IDOT received a letter from advocacy groups with comments on the Data Driven Decisions tool. IDOT's response is available here.

The department also received written comments regarding the tool as outreach occurred. A copy of those comments and the disposition is available here.

Lastly, based on the feedback received and operationalizing the tool, the department has identified some lessons learned and steps the department will continue to evaluate as the tool is refined.

As a reminder, While the comment period is closed, input is always welcome. If there are additional thoughts or comments please send an email to DOT.STIP@Illinois.gov .

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