Comparing the efficiency of the super diverging diamond interchange to other innovative interchanges’

Abstract

Innovative interchange designs are gaining attention due to their potential in reducing delays and mitigating congestion. This study was aimed at proposing the super diverging diamond interchange (SDDI) as an alternative design to the conventional diamond interchange (CDI), diverging diamond interchange (DDI), diverging partial cloverleaf interchange (DPCI), folded diamond interchange (FDI) and ramp crossover interchange (RCI) designs. An evaluation of the operational performances of the six interchange designs in terms of both vehicular and pedestrian travel times was conducted. The VISSIM micro-simulation software tool was used where several scenarios were proposed and examined. The study was carried out for the E. Mississippi Ave. and I-225 interchange in Aurora, Colorado as part of a project. Note that the interchange, mentioned, is currently operating as a CDI. ANOVA hypothesis tests were conducted to compare the travel times required for both vehicles and pedestrians to navigate each interchange type. The results indicated that, for under-saturated conditions where demand volumes were less than the interchanges’ capacities, implementing either the FDI, SDDI or RCI designs substantially reduced vehicular travel times as opposed to implementing the other designs. On the other hand, for over-saturated conditions in which traffic volumes exceeded capacities, the RCI and FDI exhibited the least vehicular travel times. The CDI was demonstrated to be the most efficient interchange serving pedestrians in all simulated scenarios. It was closely followed by the RCI and SDDI particularly for over-saturated conditions.