Complete Streets - Safety Analysis

The ability to fully quantify the expected safety benefits of Complete Streets transformations using crash-based, data-driven safety analysis (DDSA) methods such as those in the Highway Safety Manual (AASHTO 2010) is limited. The lack of crash modification factors (CMFs) for many Complete Streets treatments is a primary reason for this limitation. When CMFs for individual treatments exist, methods to combine the individual CMFs to estimate the expected safety benefits of treatment combinations on a Complete Streets project are at relatively early stages of testing. This report provides practitioners and other stakeholders with a resource that identifies and describes current capabilities, best practices, and future data and analysis needs for quantifying the safety performance effects of multiple safety treatments that agencies implement simultaneously during the conversion of typical streets to Complete Streets. The recommendations include future research needs for DDSA and future directions related to the potential use of other performance metrics that could provide additional insights into Complete Streets benefits, including broader public health benefits. The report includes three appendices that detail Complete Streets treatments, methods to develop CMFs for treatment combinations, and five case studies that illustrate the analysis methods and inform the content of the primer in chapter 4. This report can be downloaded from the US FHWA web site at https://highways.dot.gov/sites/fhwa.dot.gov/files/FHWA-HRT-24-074.pdf