Microscopic driving theory with non-hypothetical congested steady state: Model and Empirical verification

TL;DR

This paper introduces a microscopic traffic model that captures non-hypothetical congested steady states, supported by empirical data analysis and simulations that align with three-phase traffic theory.

Contribution

It proposes a new cellular automaton model explaining oscillations around the desired space gap in congested traffic, validated with empirical data and outperforming previous models.

Findings

Linear relationship between space gap and speed when speed difference is near zero

Vehicles oscillate around the desired space gap in congested flow

Model reproduces empirical phenomena and surpasses previous models in validation

Abstract

The essential distinction between the fundamental diagram approach and three-phase theory is the existence of the unique space-gap-speed relationship. In order to verify this relationship, empirical data are analyzed with the following findings: (1) linear relationship between the actual space gap and speed can be identified when the speed difference between vehicles approximates zero; (2) vehicles accelerate or decelerate around the desired space gap most of the time. To explain these phenomena, we propose that, in homogeneous congested traffic flow, the space gap between two vehicles will oscillate around the desired space gap in the noiseless limit. This assumption is formulated in terms of a cellular automaton. Simulations under periodic and open boundary conditions reproduce the empirical findings of three-phase theory. Finally, the model is calibrated and validated. All verification results are acceptable and better than that of previous studies.