C-EQ-ALINEA: Distributed, Coordinated, and Equitable Ramp Metering Strategy for Sustainable Freeway Operations

2026-01-09

arXiv.org

AI Summary

This study addresses the inequitable delay distribution among on-ramps—a common drawback of traditional ramp metering strategies that compromises fairness and system sustainability despite improving freeway efficiency. Building upon the classical ALINEA feedback controller, the authors propose a decentralized, coordinated extension that integrates four distinct fairness principles—Harsanyian, Egalitarian, Rawlsian, and Aristotelian—into the ALINEA framework for the first time. Local coordination is achieved through lightweight information exchange between neighboring ramps, eliminating the need for centralized control or additional infrastructure. Simulations of the 24-hour Amsterdam A10 ring road in SUMO demonstrate that the proposed method significantly enhances fairness in delay distribution across both ramps and users, while maintaining or even surpassing the operational efficiency of coordinated strategies such as METALINE.

Technology Category

• Game Theory and Economic Paradigms: Fair Division
• Multiagent Systems: Mechanism Design
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems

Application Category

• Economics, Online Markets and Human Computation: Fairness and ethical considerations in crowd work and in human-in-the-loop AI systems
• User Modeling, Personalization and Recommendation: Fairness-aware retrieval and ranking
• Responsible Web: Human-perceived consequences of algorithmic deployment on the web

Abstract

Ramp metering is a widely deployed traffic management strategy for improving freeway efficiency, yet conventional approaches often lead to highly uneven delay distributions across on-ramps, undermining user acceptance and long-term sustainability. While existing fairness-aware ramp metering methods can mitigate such disparities, they typically rely on centralized optimization, detailed traffic models, or data-intensive learning frameworks, limiting their real-world applicability, particularly in networks operating legacy ALINEA-based systems. This paper proposes C-EQ-ALINEA, a decentralized, coordinated, and equity-aware extension of the classical ALINEA feedback controller. The approach introduces lightweight information exchange among neighbouring ramps, enabling local coordination that balances congestion impacts without centralized control, additional infrastructure, or complex optimization. C-EQ-ALINEA preserves the simplicity and robustness of ALINEA while explicitly addressing multiple notions of fairness, including Harsanyian, Egalitarian, Rawlsian, and Aristotelian perspectives. The method is evaluated in a calibrated 24-hour microsimulation of Amsterdam's A10 ring road using SUMO. Results demonstrate that C-EQ-ALINEA substantially improves the equity of delay distributions across ramps and users, while maintaining (in several configurations surpassing) the efficiency of established coordinated strategies such as METALINE. These findings indicate that meaningful fairness gains can be achieved through minimal algorithmic extensions to widely deployed controllers, offering a practical and scalable pathway toward sustainable and socially acceptable freeway operations. Open source implementation available on GitHub.

Problem

• ramp metering
• equity
• fairness
• decentralized control
• freeway operations

Innovation

• ramp metering
• equity-aware control
• decentralized coordination
• ALINEa extension
• fairness in traffic management