ABSTRACT
The freeway interchange diversion area is the bottleneck of the traffic capacity of the interchange area and the weak point of the safety of the interchange area. The traffic flow state of the interchange section affects the traffic safety and traffic efficiency of the whole freeway. To study the mainline speed of the freeway interchange diversion area, this paper investigates the Qujiang interchange diversion area of Xi’an Ring Freeway, and obtains a large number of investigation data through field experiments. Comparing domestic and foreign specifications and studies, the traffic volume, diversion ratio, and heavy vehicle mixing rate are used as the basic indicators to reflect the traffic flow state. The mainline average speed is used to characterize the mainline speed characteristics, and origin is used to process and analyze the data. The results show that under low traffic volume, the diversion ratio and heavy vehicle mixing rate have little effect on the mainline speed. With the increase of traffic volume, the influence of diversion ratio and heavy vehicle mixing rate on the mainline speed intensifies. Relevant research conclusions are of great significance to alleviate the bottleneck of diversion area, improve traffic safety, and ensure the traffic capacity and service level of interchange.
