Research On Traffic Conflict Of Freeway Diverging And Merging Sections And Toll Booth

As the rapid development of highway, the road traffic safety is increasinglyprominent. Diverging sections, merging sections and toll boothes are theimportant parts of highway, so it is of important significance to research thesafety problem for highway traffic. In consideration of the great similaritybetween conflict and accident, more and more researchers begin to analyze andevaluate traffic safety based on traffic conflict technology instead of accidentdata analysis. For these reasons, this paper researches on the freeway interchangediverging section, merging section and toll booth, and carries out freeway safetyresearch based on traffic conflict technique.Firstly, the traffic conflict characteristics of freeway interchange divergingsection, merging section and toll booth are analyzed, then the data acquisitionand extraction scheme are formulated. And what’s more, the traffic flowcharacteristics of each section are analyzed.Secondly, based on the common traffic conflict indicator measured by timeand space, and combined with these data include the vehicle type, speed, timeheadway and others based on the features of individual vehicle, the time tocollision (TTC) model is selected to calculate rear-end conflict and the postencroachment time (PET) is developed to calculate lane-change conflict. Lastly,rear-end conflict number and lane-change conflict number are calculated basedon the models.Thirdly, the variables of prediction models for rear-end conflict andlane-change conflict are determined based on the analysis of influence factors.The prediction models for rear-end conflict and lane-change conflict aredeveloped based on the variables. And as safety assessment index the conflictrate (traffic conflict number per100vehicles) is established to better evaluate thesafety level of diverging and merging sections and toll booth, then the fuzzyassessment method for safety level is built.Finally, the Qianwei interchange diverging section, the Xingchenginterchange merging section and Sujiatun toll booth are taken as examples, andthe traffic conflict number is predicted among the survey time, then the safetylevel of these sections are determined.