1、Calibrating Fundamental Diagram of Traffic Flow and Volume-Delay Functions from Both Speed and Count DataPresented by:Arup Dutta,Ph.D.Travel Demand Modeling Program ManagerMaricopa Association of Governments Authors Maricopa Association of Governments Arup Dutta(Presenter),Wang Zhang,Haidong Zhu,Vla
2、dimir Livshits Arizona State University Xuesong Zhou,Mohammad Abbasi Acknowledgements Xin Wu(Postdoctoral Researcher at Villanova University)Conference on Innovations in Travel Analysis and PlanningKey Definitions and Concepts Capacity HCM Definition Design Capacity Ultimate Capacity V/C Ratio Volum
3、e Delay FunctionConference on Innovations in Travel Analysis and PlanningVolume Delay Function Defines relationship between the link delay and link flow As link flow increases,delay increases Many types of functions used to define this relationship Bureau of Public Roads(BPR)function Akelik function
4、 Conical function Conference on Innovations in Travel Analysis and PlanningBPR FunctionConference on Innovations in Travel Analysis and Planning Simple formulation Differentiable MonotonicBPR Function Calibration Calibrate values of alpha and beta ChallengesConference on Innovations in Travel Analys
5、is and PlanningV/C Mapping ProcedureConference on Innovations in Travel Analysis and Planning Current mapping procedures Volume based Density based New queue based mapping procedure used in our researchDefinition of Peak Hour HCM Definition:Hour with the highest traffic volume during a peak period D
6、efinition in our approach:Hour with the lowest speed during a peak periodConference on Innovations in Travel Analysis and PlanningDefinition of Peak HourConference on Innovations in Travel Analysis and PlanningVolume(veh/(hour*ln)Speed(mile/hour)Peak HourSpeed at capacityDhDV/C MappingConference on