A Three-Phase Fundamental Diagram from Three-Dimensional Traffic Data

This paper uses empirical traffic data collected from three locations in Europe and the US to reveal a three-phase fundamental diagram with two phases located uncongested regime. Model-based clustering, hypothesis testing regression analyses are applied speed–flow–occupancy relationship represented three-dimensional space rigorously validate identify their gaps. The finding is consistent across aforementioned different geographical locations. Accordingly, we propose macroscopic flow model characterization of solutions Riemann problems. work identifies critical structures that typically ignored first- higher-order models could significantly impact travel time estimation on highways.