Phase transition in traffic jam experiment on a circuit

Abstract

The emergence of a traffic jam is considered to be a dynamical phase transition in a physics point of view; traffic flow becomes unstable and changes phase into a traffic jam when the car density exceeds a critical value. In order to verify this view, we have been performing a series of circuit experiments. In our previous work (2008 New J. Phys. 10 033001), we demonstrated that a traffic jam emerges even in the absence of bottlenecks at a certain high density.In this study, we performed a larger indoor circuit experiment in the Nagoya Dome in which the positions of cars were observed using a high-resolution laser scanner. Over a series of sessions at various values of density, we found

Quantitative explanation of circuit experiments and real traffic using the optimal velocity model

“…This classification is shown in table 1. In a previous study [3], we used the data from sessions 2030 to 2934 to analyze the critical density in the Table 1. List of session IDs.…”

“…Here, we refer to the analysis of the fundamental diagram in a previous paper [3]. The critical density was obtained from a single fundamental diagram based on many sessions.…”

“…In our recent works, we have experimentally established that a transition from free flow to jammed flow is a dynamical phase transition using circuit experiments [1][2][3]. In the first experiment, we observed the instability of free flow on a circuit road, and the emergence of a traffic jam without bottleneck.…”

“…The OV model is chosen because of its simple structure and a small number of parameters. We first determine suitable values for the parameters of the OV model in the experiment [3]. The experimental values must be different from those for real traffic because the maximum velocity in a circuit experiment is smaller than that in real traffic.…”

Acquisition of the field measurement data relating to lane change actions

“…Among these, the work of Tadaki et al 2 seems perhaps the most monumental, since it entails novel experimental results using a troop of real vehicles placed on a circuit lane set in an indoor environment that excludes any noise bias resulting from an \uncontrollable" outdoor environment. This work provides a very accurate, realizable and robust data set that can be referenced by other researchers in the¯eld, who are interested in detailed processes of tra±c°ow such as phase transition, the stability of the so-called metastable phase with respect to noisy°uctuations coming from a driver's behavior, and so on.…”