A method to account for non-steady state conditions in measuring traffic hysteresis

This paper investigates the hysteresis loops commonly observed in freeway traffic flow by analyzing the evolution of speed-spacing relationships as vehicles undergo stop-and-go oscillations. The measurement method is based on the kinematic wave model with variable wave speed to account for non-steady state conditions that arise during acceleration/deceleration. We find that hysteresis takes place less frequently and in smaller amplitude than previously thought.

► We measure traffic hysteresis by tracing the speed-spacing relations of individual vehicles under stop-and-go oscillations.
► We account for non-steady state conditions that arise during acceleration/deceleration in measuring hysteresis.
► We find that hysteresis occurs less frequently and in smaller amplitude than previously thought.