The Highway Safety Information System (HSIS), established in 1987, is a foundational highway research data system. The State of Illinois has participated in the HSIS program since 1987, providing quality data to HSIS for use by researchers through a request system. In 2021, HSIS began a modernization effort with the goal of expanding the technological and analytic capabilities of the data system. This modernization provides an increased emphasis on spatial analysis and cloud-based data management.
 

What Has Changed

This guidebook is intended to support the use of Illinois HSIS data for the years 2018 and beyond. Data and documentation prior to 2011 (1985-2010) are available upon request to the HSIS Virtual Laboratory. Prior to 2011, the Illinois datasets included variables for the following files:
 

1. Roadway inventory.
2. Intersection inventory (1989-1994).
3. Horizontal curve inventory (1997-2010).
4. Accident characteristics.
5. Vehicles involved in crashes.
6. Vehicle occupants involved in crashes.

The revised Illinois database incorporated into HSIS contains 4 different files:
 

1. Roadway inventory (including traffic information).
2. Crash characteristics.
3. Units involved in crashes.
4. Persons involved in the crash.