This information guide discusses various safety assessment methods and their applicability to analysis throughout the project development process. The guide presents the following assessment methods.

• Basic methods.
  • Site evaluation or audit.
  • Historical crash data evaluation.
  • Crash modification factor (CMF) applied to observed crashes.
  • Relative comparison of CMFs.
• Intermediate Methods.
  • Annual average daily traffic (AADT)-only safety performance function (SPF).
  • SPF with CMF adjustment.
• Advanced Methods.
  • SPF with CMF weighted with observed crashes.

The purpose of the guide is to help users understand the different uses for each of the methods, as well as the scale and scope of the analyses. Safety assessment methods vary widely in level of resources required, complexity, and predictive reliability. The guide helps users select analysis methods that are appropriate in scale to the type of analysis and applicable to the phase of project development.

The guide also helps readers apply the safety assessment methods. The guide provides many examples and three detailed case study applications throughout to demonstrate the necessary calculations, common errors that analysts make, and how to interpret the results.