Analysis of unconventional arterial intersection designs (UAIDs): state-of-the-art methodologies and future research directions

The use of unconventional arterial intersection designs (UAIDs) has been advocated as a novel solution that can efficiently enhance the operational and safety performance of at-grade signalised intersections. Several studies suggest that UAIDs can lead to higher capacity, lower delays and fewer crashes. As well, these non-traditional' designs are cost-effective as only minor geometric modifications are usually required. In recent years, there has been considerable valuable research work undertaken to discuss methods for analysing the operational and safety performance of UAIDs. Nevertheless, these studies are sparse and no collective effort is currently available to identify the basic principles of the analysis of UAIDs and to determine gaps within the current methods. This article presents an in-depth literature review of existing methods of analysing the operational and the safety performance of unconventional intersection designs. These methods differ in principle issues, such as objective and scope, and in technical issues, such as experimental design, analysis tools and evaluation measures. Based on the reviewed methods, areas that need further research and improvements are identified.