Summary from: Roadway Safety Data Program | State-Specific Highway Safety Manual and Systemic Safety Analysis In Illinois | FHWA-SA-17-014

Background

The Illinois Department of Transportation (IDOT) published the AASHTO Highway Safety Manual Illinois User Guide with Illinois Calibration Factor and Default Values in 2014. This guidebook provides guidance on incorporating AASHTO Highway Safety Manual (HSM) methods into Illinois roadway safety management practices. IDOT calibrates Safety Performance Functions from the HSM for calculating the predicted crash frequency on specific roadway facility types and site types in Illinois. Also in 2014, IDOT published the Systemic Safety Improvements: Analysis, Guidelines and Procedures guidebook, and IDOT uses this guide to systemically analyze crash, roadway, and facility information, select countermeasures, and prioritize safety-related projects. IDOT employs a variety of tools and techniques to improve roadway safety in the State, including GIS integration, County Data Trees, Emphasis Area tables, Heat Maps, and a Five Percent Report.

Read the Case Study State-Specific Highway Safety Manual and Systemic Safety Analysis In Illinois for more detailed information.