White Phase Intersection Control through Distributed Coordination: A Mobile Controller Paradigm in a Mixed Traffic Stream

TL;DR

This paper introduces a distributed vehicle coordination method using a white phase where CAVs lead CHVs through intersections, significantly reducing delays compared to traditional traffic control methods.

Contribution

It proposes a novel distributed coordination strategy utilizing a white phase with CAVs as mobile controllers, formulated as a mixed-integer non-linear program with an iterative agreement process.

Findings

White phase reduces delay by up to 94.06%.

Method achieves 40.2% to 98.9% delay reduction compared to traditional signals.

Effective control across various CAV market shares.

Abstract

This study presents a vehicle-level distributed coordination strategy to control a mixed traffic stream of connected automated vehicles (CAVs) and connected human-driven vehicles (CHVs) through signalized intersections. We use CAVs as mobile traffic controllers during a newly introduced white phase, during which CAVs will negotiate the right-of-way to lead a group of CHVs while CHVs must follow their immediate front vehicle. The white phase will not be activated under low CAV penetration rates, where vehicles must wait for green signals. We have formulated this problem as a distributed mixed-integer non-linear program and developed a methodology to form an agreement among all vehicles on their trajectories and signal timing parameters. The agreement on trajectories is reached through an iterative process, where CAVs update their trajectory based on shared trajectory of other vehicles to avoid collisions and share their trajectory with other vehicles. Additionally, the agreement on signal timing parameters is formed through a voting process where the most voted feasible signal timing parameters are selected. The numerical experiments indicate that the proposed methodology can efficiently control vehicle movements at signalized intersections under various CAV market shares. The introduced white phase reduces the total delay by 3.2% to 94.06% compared to cooperative trajectory and signal optimization under different CAV market shares in our tests. In addition, our numerical results show that the proposed technique yields reductions in total delay, ranging from 40.2% - 98.9%, compared to those of a fully-actuated signal control obtained from a state-of-practice traffic signal optimization software.