| The hazard perception ability of the driver is the key factor to determine whether the driver can drive safely.Previous studies have shown that drivers with stronger risk cognition are less likely to have conflicts.Therefore,the analysis of drivers’hazard perception ability is of great significance to reduce traffic accident rate and improve the road safety.Analyzing the hazard perception ability of drivers,firstly,it is necessary to understand the cognitive response characteristics of drivers,and then study the relationships between the cognitive response characteristics and traffic crash.First of all,E-Prime software was used in this dissertation to design Oddball experiment and Go/No-go experiment combined with daily traffic scenarios,in order to study the cognitive response characteristics of drivers in selection response and discrimination response respectively.Secondly,based on the driving simulation platform,a car-following scenario with braking warning stimuli was designed to study the cognitive response mechanism of drivers in the car-following response process.Finally,based on driving simulatior,this dissertation designed emergent collision avoidance scenario at non-signalized controlled intersections,studying the mechanism of drivers’cognitive response in the process of emergent collision avoidance at intersections,and explained the causes of crash from the perspective of cognitive neuropsychology.This dissertation consists of these following four main parts:（1）Study on the cognitive characteristics of drivers’choice response to basic signal stimulation.From the perspective of cognitive neurophysiology,the differences of cognitive response characteristics of drivers when they face different traffic lights/auditory stimuli were explained,and the physiological indexes reflecting the different signals that drivers recognize when they make selective reaction were obtained.From two main sensory systems（vision and hearing）,this dissertation studies the influences of different stimuli on the cognitive characteristics of drivers in selective response.For visual stimuli,three signals were red,green and yellow traffic lights;for auditory stimuli,three stimuli were"red","green"and"yellow"audio signals.Based on the results of drivers’EEG and ERP datasets,it was found that drivers perceived signals in the order of yellow,green and red lights successively under visual stimuli.Under the auditory stimuli,drivers perceived signals in the order of"red","green"and"yellow"voice successively.The later the driver was aware of the stimulus,the longer the response time was.In addition,the study found that under visual stimuli,during the process of drivers’selection response,after visual stimulus,the negative trending troughs appeared at about 100 ms and positive trending peaks appeared at about 300 ms and 800 m at some electrodes in the frontal region of the brain.In the occipital region of the brain,there were obvious negative trending troughs at about 170 ms,and obvious positive trending peaks at about 1500 ms.In addition,by comparing the power of the brain waves,the tired drivers showed decreased brain activity during the selective reaction.（2）Study on cognitive characteristics of drivers’discriminant response to braking signal stimulation.From the perspective of cognitive neurophysiology,the cognitive response characteristics of drivers when they make discriminant reactions under go or stop decision were explained,and the physiological indexes reflecting the different signals that drivers recognize when they make discriminant response were obtained.By using the Go/No-go experimental paradigm combined with the daily car-following scene,this experiment was divided into three sub-tasks to study the cognitive response characteristics of drivers in response to the stimuli of brake lights,the whistle sound and the"brake"sound.The results showed that when drivers were doing discriminat reaction,obvious negative trending troughs appeared at 100 ms and600 ms in the anterior central gyrus and temporal region of the brain;and the obvious positive trending troughts appeared at 200 ms and 1400 ms.The forms of the stimuli had significant influences on drivers’brainwave shapes.Compared with the stimulus of brake light,the fluctuation of drivers’brainwave shapes was more obvious under the stimuli of the whistle and the"brake"voice.The results showed that,compared with the other two signals,the whistle stimulus had the best arousal effects on drivers’cognition.Under the whistle stimulus,the drivers had the highest response accuracy and the shortest response time.Based on brainwave shapes,it showed that awake drivers maintained high state of vigilance for the next stimulus,which made sure that their better performance in the next discriminative reactions,including higher button accuracy and shorter reaction time.（3）Study on cognitive response characteristics of drivers based on driving simulation experiment with car following scenario.Based on the EEG datasets,the cognitive response characteristics of drivers in the three stages of perceptual reaction,judgment and decision,and action control were analyzed,and the correlations between the EEG variables and driving behavior in these three stages were analyzed.By using the driving simulation platform,a simple car-following scenario was designed,and three types of brake warning signals were added,namely,the front vehicle’s brake light on,the whistle triggered,and the"brake"voice warning.Comparing the driving behavior performance of drivers under the three forms of warning signals,it was found that the driving performance of drivers under the stimulus of whistle was better with the shortest braking response time、the longest minimum car-following distance、the minimum average deceleration and the maximum deceleration.Furthermore,car-following process was devided into three stages,the EEG characteristics of drivers in each stage of car-following process were studied separately.In the first car-following stage,namely,the constant-speed car-following stage,the"brake"voice had the best effect on arousing drivers’cognition,and the frontal lobe of brain was more active.In the second car-following stage,namely,the braking response stage,the sound of the whristle was more likely to arouse the drivers’cognition,and the frontal and occipital lobes of brain were more active.In the third car-following stage,namely,the speed adjustment stage,brake light stimulus was more likely to induce the drivers’cognition,and the frontal and occipital lobes of brain were more active.Fatigue drivers had shorter braking response time,and there were less active in their brains.（4）Study on the impact of driver cognitive characteristics on crash risk based on driving simulation experiment with non-signalized controlled emergent collision avoidance scenarios in the intersections.Based on EEG、eye movement datasets,the characteristics of cognitive response during the emergent collision avoidance process were analyzed and the causes of traffic crash were explained from the perspective of cognitive neuropsychology.Based on the driving simulation platform,three different intersection field of view（IFOV）at non-controlled intersections were designed,this dissertation mainly studied the impacts of drivers’cognitive response characteristics on traffic safety in high-risk scenarios.By using drivers’eye movements,EEG characteristics and driving performance to explain the causes of crash at non-signalized controlled intersections.The main research conclusions are shown as follows:during the 15-second process when the driver were approaching the intersection,larger IFOV ensured drivers to fully observe the conflict objects in the search stage,then they find the conflict vehicle as soon as possible,which resulted to take actions timely and finally reduced the possibility of conflicts happening.In addition,the enough IFOV also ensured that drivers could better distribute their attention and timely divert their attention to key conflict objects,which greatly improved the level of road safety.Moreover,the conflict will happen or not can be predicted based on the driver’s EEG datasets.The results showed that the drivers’brain waves in the 2nd second before braking indluenced conflicts happening or not,safe drivers’brain waves were less active than unsafe drivers.Based on theses four experiments,drivers’cognitive response characteristics in daily traffic scenarios were discovered,and the mechanism of the impacts of cognitive response characteristics on traffic safety under high-risk conditions was analyzed.The eye-tracking technology can be used to identify drivers’hazard perception ability,EEG technology can predict whether the driver is at crash risk or fatigue state,which is of great significance for preventing traffic accidents and ensuring road safety.This dissertation contains 77 figures,36 tables and 196 references. |
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