Influencing Factors of the Length of Lane-Changing Buffer Zone for Autonomous Driving Dedicated Lanes  
[PERSON]  
1 Shandong Hi-Speed Construction Management Group Co., Ltd., Jinan 250014, China; [EMAIL_ADDRESS] (F.H.); [EMAIL_ADDRESS] (S.W)1 Shandong University of Transportation, Southeast University, Nanjing 211189, China; [EMAIL_ADDRESS] (Z.S.  
through vehicle-to-everything (V2X) technology and computer vision. This gives traffic design an important position in achieving efficient and safe autonomous driving technology in real life. In lane design, it is generally recommended to set the innermost lane as the dedicated lane [2]. Such a design approach reduces both the interference experienced by AVs and the cost of retrofitting existing highways, which is a more economical solution to guarantee the right of way for AVs on highways [3]. In this case, an AV approaching from outer lanes would process a series of lane changes to enter the innermost dedicated lane. As an insurance strategy to ensure safe and efficient lane changes, a \"buffer zone\" in the outer lane adjacent to the dedicated lane is required to \"alert\" the AV to perform a lane change. The buffer zone is intended to \"alert\" the AV to enter the dedicated lane when favorable, as shown in Figure 1. The buffer zone is set in the adjacent lane at the start position of the autonomous driving dedicated lane. The road surface pavement of the buffer zone is set in a special color for the easy identification of AVs. The purpose of setting the buffer zone is twofold. First, the buffer zone is the signal that requires the AV to enter the dedicated lane. After the AV successfully identifies the buffer zone, it uses the lane-changing behavior to enter the dedicated lane. Secondly, the buffer zone can guarantee the safety of AVs during the lane-changing process. The length of the buffer zone is crucial for studying traffic design solutions for autonomous driving roads. Therefore, it is especially important to determine the longitudinal driving distance of vehicles during the lane-changing process by studying lane-changing behavior and its influencing factors for the traffic design of autonomous driving roads.  
Focusing on buffer zone length, this study investigates the research on longitudinal driving distance during the whole lane-changing procedure and analyzes the influence of several factors. Limited by technical conditions, there is no highway condition at the moment that is able to provide corresponding mixed traffic flow trajectory data containing the interference of AVs. This work adopts the trajectory data set NGSIM (Next Generation Simulation) to study the lane-changing behavior of vehicles. With the analysis of HDV characteristics of lane-changing behavior, the longitudinal driving distance of lane-changing vehicles is understood. The contribution of this study is to use the principal component analysis method to explore the influencing factors of the longitudinal driving distance from both qualitative and quantitative points of view, which provides a theoretical basis on the design for the buffer zone length.  
The structure of this paper is as follows. Section 2 summarizes the existing research on lane-changing behavior and discusses the influencing factors of the lane-changing procedure. Section 3 focuses on the methodology adopted in data processing, model building, and testing. Section 4 processes NGSIM data, studies influencing factors, and models the longitudinal driving distance of the lane-changing process. Section 5 selects the general linear regression model to compare with the proposed PCA model in this paper,  
Figure 1: The layout of the dedicated lane and the buffer zone.  
and discusses the factors affecting the buffer zone length design from a qualitative point of view. Section 6 concludes the content.