# Research on Geometric Design Standards for Freeways under a Fully Autonomous Driving Environment
## 2 Literature Review
In addition, the results of this study show that by implementing the multi-vehicle communication system's CAV in the highway section, the traffic efficiency and safety of the road are significantly improved. Chinese scholars' research on autonomous driving technology in an autonomous driving environment mainly focuses on the application of the Internet of vehicles, visual perception technology and sensor technology of autonomous vehicles, safe distance models, and matching of autonomous vehicles with current road standards, sexual analysis, and thinking. [PERSON] [18] and others designed a control system for autonomous obstacle avoidance for autonomous vehicles. The system monitors and detects real-time traffic conditions in the adjacent lanes of autonomous vehicles through sensor technology and image processing technology. At the same time, according to the road conditions in front of the vehicle, the system can automatically change lanes safely and smoothly during vehicle operation. [PERSON] [19] simulated and analyzed a scene of an autonomous vehicle leaving the main line according to the car-following characteristics and lane-changing model of the autonomous vehicle. On this basis, he proposed a path control strategy for autonomous vehicles to exit the main line and enter the exit ramp. Moreover, he optimized the control strategy and established a related evaluation model through the designed simulation experiments. [PERSON] [20] reduced the interference of other road marking information on the lane line recognition effect by performing grayscale processing, noise reduction processing, and separation on the image information collected by the video collector. Then, he extracted the lane line feature points and calculated the position of the lane's center line. Finally, he obtained the centerline of the lane by fitting these feature points and proposed a method that can combine the real-time position information of the vehicle to realize the lane departure warning of the autonomous vehicle. [PERSON] et al. [21] studied the braking performance of autonomous vehicles on straight road sections and curved road sections through CarSim/Simulink simulation experiments based on the braking principle of autonomous vehicles, the texture characteristics of asphalt pavement, and the braking model of the vehicle. Based on the research results, they proposed the braking distance requirements of autonomous vehicles at different design speeds. Most of the current research focuses on the development of connected autonomous vehicles in a fully autonomous driving environment, road environment recognition, the mechanism of autonomous vehicles overtaking, the modeling and simulation of mixed human-machine driving traffic flow, and autonomous driving laws and regulations, etc. There is little research on road technical indicators in an autonomous driving environment, which mainly focuses on the vertical curve length and the stopping sight distance. Few scholars have considered the applicability of traditional road design standards and autonomous driving traffic characteristics. In addition, few scholars have explored and systematically studied the design standards and technical indicators of freeways in a fully autonomous driving environment.