Research On The Influence Mechanism Of Human And Vehicle Physical Behavior Of Major Casualties

Although the probability of major casualties is low in road traffic accidents,the social impact and property losses caused by it are several times or even dozens of times of other accident categories.In a major casualty,vehicles and occupants will undergo a series of actions in the physical space in which they are located,such as vehicle rollovers,personnel ejections,etc.These actions are called human and vehicle physical behaviors in this paper.There are few studies on the physical behaviors of human and vehicle in major casualties,and most of the studies based on simulation experiments,which is different from the actual situation.Foreign countries used many statistical models to explore the mechanism of the physical behaviors from the actual accident data,but they are less involved in the research on the mechanism of those behaviors in combined mode.Based on this,according to the actual road traffic accident data of the National Highway Traffic Safety Administration General Estimate System from 2013 to 2015, this paper uses multivariate statistical methods to analyze the relationship between the three physical behaviors(vehicle rollover,airbag deployment and personnel ejection)in major casualties and 12 influencing factors(vehicle speed,weather,vehicle type,etc.),for the purpose of obtaining their influence mechanism.Then some effective improvement measures are proposed.Firstly,by using the binary and multivariate logistic regression model,the influence mechanism of influencing factors on the three physical behaviors in a single situation and a combination situation is analyzed,and vehicle's speed and whether used the seat belt which are two key factors that have important affects both in the single state and the combined situation are obtained,and the general rule of influencing results of the factor in the combined state is presumed by the influence in a single state Then,through the semi-parametric logistic regression model,the smoothing effects and interaction effects of the two key influencing factors are analyzed,and important velocity nodes are captured.The results show that the driving speed of the vehicle has the same influence on the three physical behaviors.The risk of the three physical behaviors will increase with the increase of the speed,and the impact on the personnel ejection is the greatest,the vehicle rollover is the second,and the airbag deployment is the lowest.The trend is more significant when considering the use of the seat belt.Considering the effect of speed on three physical behaviors,three key speed nodes can be identified:50 km/h,100 km/h and 120 km/h.At these three speed nodes,it can not only maintain the smooth impact of speed on the risk of certain behaviors,but also minimize the risk of other behaviors,which can provide relevant theoretical support for the formulation of the speed limit policy.Finally,based on above analysis results,this paper gives corresponding safety improvement programs from the aspects of speed limit adjustment,traffic infrastructure optimization,and risk transfer to reduce the risk of major casualties and minimize the life losses and property damage.