Estimating Fundamental Diagram for Signalized Intersections Using Connected Vehicle Data

The fundamental diagram (FD) is to describe the macroscopic relationships between traffic flow and density. It is widely used in the traffic analysis for freeways and urban streets.(1-3) In previous studies, the aggregated empirical measurements from detectors are commonly applied to fit the diagram.(4, 5) However, this detector-based method has data quality issues related to detector installation or the deterioration of the pavement, and a methodology issue because the detectors at fixed locations cannot fully capture vehicle dynamics.(6) In this study, a set of connected vehicles (CV) trajectory data is considered to construct a FD (i.e., flow-density relation) at a signalized intersection based on the traffic states.