Self-Organized Criticality of Traffic Flow

This paper shows that the kinematic wave model exhibits self-organized criticality when initialized with random initial conditions around the critical density. This has several important implications for traffic flow in the capacity state, such as: \item jam sizes obey a power law distribution with exponents 1/2, implying that both the mean and variance diverge to infinity, \item self-organization is an intrinsic property of traffic flow models in general, independently of other random perturbations, \item this critical behavior is a consequence of the flow maximization objective of traffic flow models, which can be observed on a density range around the critical density that depends on the length of the segment, \item typical measures of performance are proportional to the area under a Brownian excursion, and therefore are given by different scalings of the Airy distribution, \item traffic in the time-space diagram forms self-affine fractals where the basic unit is a triangle, in the shape of the fundamental diagram, containing 3 traffic states: voids, capacity and jams.