Research on Speed Limit Method of Expressway Main Road Based on Rainy Environment and Its Influence on Vehicle Confluence

The expressway plays a vital role in alleviating urban traffic congestion, and the meteorological environment and traffic flow characteristics are the key factors affecting the capacity. Therefore, implementing corresponding control of the expressway is an important measure to ensure its capacity. Based on the investigation and analysis of the characteristics of expressway traffic flow in rainy environments, considering the influence of main road speed limit on safe confluence, this paper proposes a method of speed limit control for the expressway main road in rainy environments based on macroscopic dynamic traffic flow METANET model from the real-time running state of the expressway. The method is validated by an experimental simulation. The results show that the speed, acceleration, queue delay, and travel time of the vehicle confluence are reduced after implementing the reasonable speed limit control in rainy environments, which is conducive to the smooth confluence and traffic safety in rainy weather.