Which publication does IDOT release annually to highlight key performance metrics?

The correct choice is the Illinois Transportation Fact Book, which is an annual publication by IDOT that provides a comprehensive overview of vital statistics and performance metrics related to transportation in Illinois. This fact book includes data on various aspects of the transportation system, such as roadway conditions, safety statistics, traffic volumes, and funding sources. Its purpose is to inform stakeholders, policymakers, and the public about the state of transportation within Illinois and to help in decision-making processes regarding infrastructure and investment.

The other options, while related to transportation or IDOT's initiatives, serve different roles. For instance, the IDOT Annual Report typically outlines the department’s accomplishments over the year but may not focus specifically on performance metrics in the same comprehensive and detailed manner as the Fact Book. The State of Illinois Infrastructure Report may assess the broader infrastructure needs and conditions but is not specifically an annual performance metric report. Lastly, the Transportation Improvement Plan details projects that are to be implemented but does not primarily focus on performance metrics as gathered in the Fact Book.