Transportation agencies throughout the United States have been steadily designing and implementing a variety of alternative intersections and interchanges (AIIs) to address unique safety and operational problems. However, despite the growing number of AIIs, high-quality crash prediction models and crash modification factors (CMFs) used to quantify the benefits of these designs remain limited.

NCHRP Research Report 1195: Developing Crash Modification Factors for Alternative Intersections: A Guide, produced by TRB’s National Cooperative Highway Research Program, includes an abbreviated literature review focusing on the three types of AIIs studied and potential analysis methods, as well as a discussion of data collection and analytical approaches. It summarizes the results of CMF development and presents a case study on the use of safety performance functions (SPFs) in future analyses. The report also presents the movement-based SPF framework and results, documents a microsimulation case study, and offers suggestions for implementing the CMF findings and conducting future research.