Simulation Study On Driving Safety Of Driverless Vehicles In Urban Environment

With the development of intelligent vehicles,driverless cars will gradually become the development direction of the future automobile industry.Driverless cars can effectively avoid many mistakes of manual driving,thereby improving the safety and efficiency of road traffic.In view of the current technological development,it is difficult to achieve the transition from manned to completely driverless transportation system in a short time,and the state of mixing manned and driverless traffic will exist for a long time.Therefore,it is particularly important to study the impact of different proportions of driverless cars on road safety in urban traffic systems during the transition from human to driverless.This article takes typical urban scenes as research objects,uses micro-simulation technology to build different urban road models,and uses surrogate safety assesment models to evaluate safety in different scenes.By setting different penetration rates of driverless cars,the law of market penetration rate on urban traffic is evaluated in terms of traffic efficiency and safety.This paper uses the open source Simulation of Urban Mobility SUMO and SUMO-based surrogate safety assesment models SSM to conduct driverless safety research.Three research objects were selected: typical urban road sections,intersections,and urban expressway ramps,and road simulation scenarios were set according to national standards.After designing the experiment and running the simulation model software,the total number of conflicts and the number of various types of conflicts under different traffic environment parameters are counted.According to conflict data and traffic efficiency,the imfluence of permeability change on traffic safety is obtained.The research results show that:(1)The main type of conflict in the road segment is rear-end collision;Compared with Adaptive Cruise Control(ACC)vehicles,Cooperative Adaptive Cruise Control(CACC)vehicles exhibit higher safety performance.Vehicle speed has a significant negative impact on the number of CACC conflicts.At higher speeds,the proportion of high-penetration driverless vehicles is more conducive to driving safety;at lower speeds,the proportion of low-penetration driverless vehicles is more conducive to driving safety.(2)When the intersection is in the middle and low flow,collision conflict is the most important type of collision.When the traffic flow is large,rear-end collision is the most important type of collision.Compared with CACC vehicles,ACC vehicles show higher safety.The traffic flow has a significant positive effect on the number of ACC conflicts.(3)The main type of conflict on urban expressway ramps is rear-end conflict;Compared with CACC vehicles,ACC vehicles show higher safety;Ramp traffic and mainline traffic have a significant positive impact on the number of ACC conflicts.The conclusion of this study can provide a reference for the safety of driverless vehicles on different urban roads,which is of great significance for improving road safety.