Speed limit control in confluence area for improving access condition considering carbon emissions

This paper aims to explore carbon emissions and determine corresponding improvement methods based on road access conditions, thereby achieving the ‘dual carbon’ goal based on road traffic. In this study, models of access conditions and traffic carbon emissions are first determined, and the desired speed model is further determined based on the minimum growth rate of traffic carbon emissions, while the speed limit control model is constructed. Then, based on the actual confluence area of expressways, statistical methods, and simulation methods, the relationship between road access conditions and traffic carbon emissions is explored, and the desired speed is also determined; meanwhile, changes in traffic efficiency, speed, and traffic carbon emissions under speed limit control are analysed. Finally, the reasons for synchronous changes in traffic carbon emissions and traffic efficiency are discussed, and the effectiveness of speed limit control is compared and analysed. The results show that speed and the number of vehicles per unit of time are the main factors of synchronous changes, and the essence lies in the change in traffic states. In addition, speed limit control plays a certain role in improving traffic conditions in the confluence area.