Innovative Operational Strategy for Variable Speed Limits Based on AV Spacing Policy Under Mixed Traffic, with a Sustainable Approach

It is well known that the features of self-driving vehicles depend on communication technologies to demonstrate their benefits. Since these technologies are still under development and face numerous obstacles, this highlights the need to develop a modern approach to solving congestion during the transitional phase. In this study, we worked on developing an integrated new operational strategy that maximizes the benefits of the variable speed limit strategy and expands its impact by coordinating its operation with the spacing policy mechanism in vehicles equipped with adaptive cruise control (ACC) to provide an innovative approach aims to operate vehicles with low levels of autonomy and leverage their ability to maintain short time gaps to operate as an effective category to improve traffic conditions, aided by existing transportation systems. To achieve this, we employed PTV-VISSIM to develop the VSL algorithm, which was coded using the VisVAP interface. We also used VISSIM features to model and develop the characteristics of the ACC vehicles and the spacing policy. Different control strategies were tested individually and in combination at various penetration rates, and the results demonstrated the superiority of our proposal to integrate the VSL mechanism with the short-time gap recommendation strategy. The strategy’s effect was also evident in emissions reductions of 52% to 86% and in fuel consumption decreases of 52% to 87% compared to the no-control scenario, and of 56% to 28% compared to the typical VSL scenario, supporting an environmental sustainability approach in traffic strategies.