Study On Stopping Behavior During Yellow Signal Interval At Signalized Intersections Considering Driver Heterogeneity

At the onset of the yellow signal at signalized intersections,drivers' inappropriate stopping behavior is one of the major cause of accidents during the yellow signal interval.In addition,the distraction from the use of mobile phone is another contributor to traffic accidents.In order to ensure driver safety and reduce the accident rate during the yellow signal interval,this study investigates driver stopping behavior,especially when it is distracted by the mobile phone,the stopping time(from the onset of the yellow signal to the time when the car stops completely)is chosen as the research object.Meanwhile,different drivers may have different stopping preferences and characteristics.Thus taking into the consideration of driver group heterogeneity,this study would examine the influencing factors,including driver demographics,traffic condition,and mobile phone use by subtasks,that could affect stopping time of different types of drivers during the yellow signal interval.What's more,when it comes to the driver individual heterogeneity,this study would analyze driver stopping behavior with the consideration of inter-driver heterogeneity and intra-driver heterogeneity.The results of this study will help to better understand the stopping behavior of drivers among different characteristics during the yellow signal interval.The main tasks are as follows:(1)Exploration of the distribution of driver stopping time.Based on the driving simulator data,the survival function and hazard rate function of driver stopping time was established to figure out drivers' survival rate and the hazard rate.The results showed that most drivers preferred to make a quick stop during the yellow signal interval.(2)Comparison of stopping time of drivers with different characteristics.Use the Log-Rank Test and Generalized Wilcoxon Test to compare the differences of driver stopping times in terms of different age,gender,phoning pattern,and phoning status.The study found that both age and gender variable had a significant impact on the driver stopping time,however,phoning pattern and phoning status had no significant effect on it.To be specific,women and the middle-aged driver had higher stopping rate.(3)Analysis of driver stopping time considering driver group heterogeneity.A Classification and Regression Tree(CART)-based Accelerated Failure Time(AFT)model was developed to classify drivers into thirteen groups.Within each group,the unique influencing factors were explored with emphasis on the impacts of mobile phone distractions.The results showed that the proposed CART-AFT model could predict driver's potential dangerous stopping behavior,explore unique factors that influence the stopping behavior of different types of drivers,and explain the different roles of the same factor in the stopping behavior of different types of drivers.As for the impact of mobile phone use on driver stopping behavior,the results showed that distracted drivers would decelerate more rapidly and brake more aggressively to compensate for the risk of a telephone conversation.And none of the phoning pattern(i.e.,handheld,headset,hands-free call)would reduce the negative impact on the drivers' driving stability.That is,the negative effect of mobile phone use comes from the phone distraction itself rather than the different phoning pattern.(4)Analysis of driver stopping time considering driver individual heterogeneity.Driver individual heterogeneity consists of inter-driver heterogeneity and intra-driver heterogeneity.And the intra-driver heterogeneity refers to the correlation between repeated measures of the driver in the driving simulation experiment.In order to analyze driver stopping behavior with the consideration of driver individual heterogeneity,firstly,the Univariate Frailty Model and Random Parameter AFT Model were developed to take inter-driver heterogeneity into account.Secondly,when it comes to the intra-driver heterogeneity,the Shared Frailty Model was established.Finally,the results showed that the "Distance to Stop Line at the onset of Yellow Signal" and the "Vehicle Speed at the onset of Yellow Signal" are the key factors affecting the drivers' stopping behavior.