The Highway Safety Manual (HSM) has made predictive safety analysis feasible for many basic roadway elements, including freeway and ramp segments and ramp terminals. This capability raises the expectation for predicting the safety performance of more complex roadway facilities, such as interchanges. Although interchanges can be decomposed into basic road elements, the safety performance of interchanges cannot be derived by simply adding predictions from individual components.

This user guide assists safety professionals in applying the predictive methodology and using the accompanying implementation tool. This guide provides details on applying the predictive method to an interchange area and how that fits into the context of the overall interchange influence area. Additionally, this user guide details where the predictive method is applicable and the required inputs and supporting calculations. Finally, this guide provides instructions on using the spreadsheet implementation tool and interpreting the spreadsheet inputs and outputs.

Recommended citation: Federal Highway Administration,Interchange Comparison Safety Tool User Guide (Washington, DC: 2023) https://doi.org/10.21949/1521985