Study On Child Pedestrian Road Crossing Characteristics And Traffic Safety In School Zone

With the rapid improvement of urban motorization in China,the traffic environment becomes more and more complicated.Children as vulnerable groups of road users,especially children pedestrian,are more likely to be hurt in traffic accidents.Walking is one of the major transportation modes for children in our country.During the school commute time,high intensity pedestrian flow is concentrated at the intersections of school zone,and at the same time non-motor vehicles and motor vehicles which used to transfer students mix with pedestrian,lead traffic congestrion and traffic safety problem.In addition,the physical,psychological and cognitive aspects of children are still developing,and have not yet become mature.Therefore,they are limited in the ability of making safe crossing decision,and more likely to take risky behavior actively,which make them have higher risk of being involved in traffic crashes or injuries.Accordingly,researching on children pedestrian crossing has an important significance for improving the safety and efficiency of children pedestrian crossing the street and reducing the injury of children pedestrian.But the safety of children pedestrian crossing has not attracted enough attention,the improvement measures implemented by school and government are also lack of certain theoretical basis.Under such a background,it has great theoretical and practical significance to explore the traffic characteristics and traffic safety of children pedestrian crossing.Therefore,the purpose of this study is focusing on the traffic characteristics,modeling methods and safety evaluation of children pedestrian crossing at school intersections.In order to provide theoretical basis and method guidance for the design of pedestrian traffic facilities,the management and control of traffic flow,and improving the traffic efficiency and safety of the intersections in school zones.In this paper,the basic traffic characteristics and safety of children pedestrian crossing are systematically analyzed based on the traffic survey data at first.Secondly,based on the study of pedestrian traffic flow theory,combined with the behavior characteristics of children pedestrian crossing and the mechanism of non-motor vehicle interference,a model of gravitational cellular automata for children pedestrian crossing and a coupling model of mixed traffic flow between non-motor vehicles and pedestrians are established.Then,based on the analysis of children's behavior decision-making and traffic conflict analysis,a traffic safety evaluation model for children pedestrian crossing is established.Finally,on the basis of these work,the strategies of improving the traffic safety of children pedestrian crossing in school zones are put forward,and the simulation and evaluation system of the children pedestrian crossing traffic is designed.The main research works and achievements are summarized as follows.The traffic data of children pedestrian crossing the street were collected through questionnaires and observation.The self-evaluation awareness and behavior of children pedestrian crossing and demographic characteristics were obtained by questionnaire survey,and the real behavior and dynamic characteristics of children pedestrian crossing the street were obtained through observation survey.Then the basic characteristics and behavior safety of children pedestrian crossing were systematically analyzed,to explore the related factors that affect the characteristics and safety of children pedestrian crossing.Based on the statistical analysis of children's walking speed,the reference value of childrenss walking speed under different conditions was suggested.Two school intersections were selected to analyze the influence of the pedestrian countdown signal on the behavior and safety of children pedestrian crossing.On the basis of the pedestrian cellular automata model,profiting from magnetic force model and floor field model,the destination attraction to pedestrian,the attraction of the blank area and the same direction pedestrians,the rejection of the opposite direction pedestrians,the attraction of companions are using gravity fomula to describe,a gravitational cellular automaton model of children pedestrian crossing were established.Children crossing accompanied with classmates and parents are the significant characteristics.The evolution rules of single pedestrian were proposed first,and then the evolution rules of parent-child combination and children combination were proposed.The micro crossing behavior and macro characteristics of children pedestrian were simulated and analyzed under different situations.The simulation results of the movement state of the pedestrian flow showed that the self-organizing channels were formed quickly when there were no parents and children companions.To a certain extent,parents and children companions had negative effects on the self-organizing channel forming.The analysis results of pedestrian crossing speed also indicated that the behavior of parents and children accompanying led to the decline of overall pedestrian crossing speed.Considering the mix traffic of non-motor vehicles and pedestrians at the intersections in school zones,children pedestrians were affected by the non-motor vehicles when crossing the street.The NS model of non-motor vehicles was embedded into the model of pedestrian gravitational cellular automata model to establish the coupling model of pedestrians and non-motor vehicles.In the model,evolution rules of non-motorized vehicles were described based on benefits of lane changing,and the mutual interference mechanism between children and non-motor vehicles was analyzed.The simulation results of the dynamic process of the mixed traffic flow crossing the street showed that the non-motor vehicles and pedestrians interfere with each other,causeing local traffic congestion easily.Besides,the greater flow of non-motor vehicles,the lower the average speed of pedestrian crossing,theaffects were obvious when children accompanied with classmates or parents.Electric bicycles and electric tricycles had greater impacts on children's crossing speed,it was more likely to cause traffic congestion when mixed with pedestrians.The larger the area of mixed traffic between non-motorized vehicles and pedestrians,the slower the overall crossing speed.The retrograde violations of non-motorized vehicles had greatly interfered with children's crossing speed,which was likely to cause serious congestion.Not looking left and right before crossing,running to cross and herd behavior are the common behavior of children pedestrian.A safety evaluation model for children pedestrian crossing at unsignalized intersections was proposed,based on the analysis of behavioral decision and traffic conflict.The safety of children pedestrian crossing was quantized classifying through the calculation of the risk degree function value,and the factors affecting the safety of children pedestrian were discussed.The results showed that the greater flow of motor vehicles,the higher speed of motor vehicles,the lower degree safety of children pedestrian crossing.The longer the crossing distance was,the higher risk of crossing the street for children.The two-stage crossing mode for children crossing was safer than one-stage crossing,especially when the traffic flow was high and the crossing distance was long.The behavior of not looking before crossing and running to cross increased the traffic conflicts with motor vehicles,reduced the safety of children pedestrian crossing.The problems existing in children pedestrian crossing in school zone were summarized,combined with the research results of this paper,the strategies of improving children pedestrian crossing safety were put forward from the aspects of traffic engineering,traffic management,traffic safety education and traffic safety regulations.On the basis of the simulation model of children pedestrian crossing behavior and the safety evaluation model established in this study,the simulation system for children pedestrian crossing and safety evaluation was designed,to improve the applicability and practicability of the model.Through the simulation,the dynamic process of children pedestrian crossing the street can be reproduced,the characteristic data and safety indexes of children pedeststrian crossing were recorded.The selected intersection in school zone was taken as an example to show the system application.