The Many Roles of the Relaxation time Parameter in Force based Models of Pedestrian Dynamics

In force based models of pedestrian traffic, the relaxation time, τ, is related to the time it takes a pedestrian to adapt its motion to its preferences. An example of this is linear acceleration, but τ is also connected to how the agent adjusts to spatial variations in its preferred velocity, and affects evasive maneuvers. These many roles of τ may be a problem when calibrating force based models.We compare linear acceleration, to new data on, and simulations of, turning movements. The results indicate that the models predict drifting of a magnitude that is not supported by the data.