The Highway Safety Information System (HSIS) is a roadway-based system that provides quality data on a large number of crash, roadway, and traffic variables. The system comprises data collected by States for managing the highway system and studying highway safety. HSIS is composed of seven States and one urban center: California, Illinois, Ohio, Maine, Minnesota, North Carolina, Washington, and Charlotte, NC. HSIS includes some agencies’ highway intersection, interchange, lighting, and curve/grade data. Additional supplementary information includes vulnerable road user infrastructure data, such as sidewalks, greenways, and transit stops.

This guidebook is part of a series of data guidebooks for each HSIS agency that explain the variables and attributes provided by each agency. Each guidebook describes the agency’s data system and presents an alphabetized listing of all available variables. All data are derived from police-reported crash records, maintained highway records, and other supplementary inventories.