With the increased emphasis on highway safety, nationally and with many local agencies, more individuals look to the Highway Safety Manual (HSM) for guidance on how to reduce fatalities and serious injuries on roadways. However, it may be difficult for new users of the crash prediction methods in HSM Part C to understand the various definitions, facility types, facility features, and input values used in the many safety performance functions (SPFs), adjustment factors (AFs), and crash modification factors (CMFs). This lack of understanding can lead to the improper application of the HSM predictive methods. 

The objective of this research is to develop a graphic resource (i.e., a document with many illustrations) to assist practitioners to understand the data elements and definitions used in HSM crash prediction methods. 

The graphic resource will serve as a companion document to the HSM, second edition. The document will focus on providing real-world illustrations to help practitioners understand the various prediction method input parameters and data elements. The graphic resource will follow a style and layout similar to the HSM, second edition.