Flow-level Coordination of Connected and Autonomous Vehicles in Multilane Freeway Ramp Merging Areas

TL;DR

This paper proposes a flow-level coordination strategy for connected and autonomous vehicles to improve multilane freeway ramp merging efficiency, reduce congestion, and enhance traffic flow stability through real-time optimization and platooning.

Contribution

It introduces a novel multilane CAV coordination framework that integrates lane-changing, gap creation, and platooning, extending existing single-lane strategies to more realistic multilane scenarios.

Findings

Significant improvement in ramp merging efficiency.

Reduction in recurrent traffic congestion.

Enhanced traffic flow stability under high volume.

Abstract

On-ramp merging areas are deemed to be typical bottlenecks for freeway networks due to the intensive disturbances induced by the frequent merging, weaving, and lane-changing behaviors. The Connected and Autonomous Vehicles (CAVs), benefited from their capabilities of real-time communication and precise motion control, hold an opportunity to promote ramp merging operation through enhanced cooperation. The existing CAV cooperation strategies are mainly designed for single-lane freeways, although multilane configurations are more prevailing in the real-world. In this paper, we present a flow-level CAV coordination strategy to facilitate merging operation in multilane freeways. The coordination integrates lane-change rules between mainstream lanes, proactive creation of large merging gaps, and platooning of ramp vehicles for enhanced benefits in traffic flow stability and efficiency. The strategy is formulated under an optimization framework, where the optimal control plan is determined based on real-time traffic conditions. The impacts of tunable model parameters on the produced control plan are discussed in detail. The efficiency of the proposed multilane strategy is demonstrated in a micro-simulation environment. The results show that the coordination can substantially improve the overall ramp merging efficiency and prevent recurrent traffic congestions, especially under high traffic volume conditions.