Sight Distance Reliability Analysis Of Unmanned Vehicles And Research On Highway Route Utilization Strategies

With the upgrading of people’s travel needs and the advancement of artificial intelligence,driverless cars are considered to be an important mode of transportation in the future.Many scholars have carried out research on unmanned driving technology,and research on unmanned driving from the perspective of highway facility design impact is also one of the focuses.Among them,sight distance is a key factor in road alignment design and an important indicator affecting road design and driverless driving safety,especially on expressways.Therefore,this paper takes the expressway with the central divider as the research object,assuming that roadside obstacles are continuous and will block the perception range of unmanned vehicles on horizontal and vertical curve sections,and introduce the reliability theory to analyze the reliability of the stopping sight distance value corresponding to the highway route design index in the unmanned driving environment,and the utilization strategy of the existing highway route in the unmanned driving scenario is proposed accordingly.The paper first analyzes the differences in perception,decision-making and control execution between unmanned and manned driving based on the characteristics of unmanned vehicles and the architecture of unmanned vehicles,provides a basis for the selection of parameter values in the analysis of unmanned driving sight distance.Then,on the basis of analyzing the influencing factors of parking sight distance,based on the parking sight distance model of manned driving and the characteristics of unmanned driving,the computational model of stopping sight distance of unmanned driving is established,and the recommended stopping sight distance value corresponding to the expressway design speed is calculated.Secondly,based on the reliability theory,unmanned driving line-of-sight requirements and Monte Carlo method,the reliability probability corresponding to the minimum value of the horizontal curve and vertical curve specified in the current route specification is calculated,and the influencing factors of stopping sight distance reliability are analyzed.On this basis,the recommended values of the horizontal curve radius and vertical curve radius of the 120km/h,100km/h,and80km/h design speed routes under the 95%and 99.9%stopping sight distance reliability probability are given.Finally,under the condition of unmanned driving,the strategy of using the existing road route as it is,decelerating appropriately and rebuilding it according to the situation is proposed,and a case verification is carried out on a certain expressway.The research shows that under the premise that the initial speed,reaction time,deceleration and other random variables conform to the normal distribution,when the average initial speed is the design speed,the average reaction time is 0.2s,the average braking deceleration that satisfies comfort is 3.4m/s~2 and ensures safety is 4.51 m/s~2 and the coefficient of variation is 0.1,as far as the minimum value of the radius of the horizontal and vertical curve stipulated in the current route design code is concerned,the failure probability corresponding to the stopping sight distance is relatively high.But for the actual route design scheme,in most cases,it can meet the 95%reliability probability requirement of the stopping sight distance.