Development of Crash Modification Factors for Continuous Flow Intersections

Abstract

Innovative intersections are defined as any at-grade design concepts that are able to reduce the number of signal phases at the main intersection. The Continuous Flow Intersection (CFI) displaces the left turns from the main intersection approach using an additional upstream crossover, allowing the left turns to run concurrently with the through movements. This improves operations and increases the intersection capacity. It also benefits safety by reducing the number of conflict points. This paper presents a safety analysis and the development of Crash Modification Factors (CMF) for CFIs using the Empirical Bayes (EB) methodology. The methodology is applied to before and after crash data for eight treatment sites (conversion to CFI) and five sites in the comparison group. The results show that CFIs experience about 12% less total crashes after conversion. Further analysis needs to be conducted for different crash types and crash severity.