Exploring corridor operations in the vicinity of a diverging diamond interchange (DDI) : final report.

Final report, August 2013 to May 2016PDFTech ReportFHWA/NC/2014-132014-13CostsDiamond interchangesField studiesGeometric designHighway corridorsMicrosimulationTraffic delayTraffic signal phasesTraffic signal timingTraffic simulationTraffic volumeUnited StatesNorth CarolinaNorth Carolina. Dept. of TransportationCunningham, Christopher M.Warchol, ShannonSchroeder, Bastian J.North Carolina State University. Institute for Transportation Research & EducationNorth Carolina. Dept. of Transportation. Research and Analysis GroupUnited States. Federal Highway AdministrationUS Transportation CollectionThis research effort examined the corridor impacts of various signal timing and geometric strategies to improve theoperational challenges observed at DDIs. A microsimulation analysis was conducted using a calibrated and validated DDImodeled after the National Avenue and US-60 interchange in Springfield, Missouri. Four heavy volume scenarios weretested in combination with seven categories of strategies. These strategies were selected from a larger pool of strategiesunder the guidance of the NCDOT research panel and national expert recommendations. In addition to the microsimulationeffort, a cost analysis was conducted for the same strategies. Considerations were made for implementation cost, disruptionto user during implementation, and crash modification impacts. Finally, three sites in North Carolina were selected for fieldstudy. In the microsimulation analysis, those strategies which reduced the number of phases at the downstream adjacentintersection had the greatest benefit on the corridor routes for all four heavy volume scenarios. The reduction in phasesreduced loss time and increased capacity for the intersection. Unfortunately, these strategies were also the most expensivealternatives studied, were likely to be the most disruptive to users during implementation