Abstract
As an effective method, Traffic Conflict Technology (TCT) is widely applied to estimate the safety level of some risky areas, especially for the merging areas in the urban roads. Most of researchers prefer to just exploit the promising safety assessment models using realistic traffic data to predict the numbers of conflicts. There are a few types of research focusing on how to predict traffic conflict assessment indexes precisely in merging areas. Despite some related studies have realized this critical dilemma, significant lane-change characteristics are usually ignored and it is worthwhile devoting much effort to this. Hence, a modified Post Encroachment Time (PET) model is proposed in this study, to figure out lane-change characteristics as well as accurately forecast traffic safety of the merging area. Unlike other conventional methods, such as Time to Collision (TTC) or PET models, the proposed model not only fully takes the lane-change characteristics of merging vehicles into consideration, but also it explores the safety requirements in the process of lane changing in details. Moreover, the calculation formula of the modified PET model is gradually deduced by the trajectory of merging behavior and velocity formula. Besides, for the sake of pursuing a high validity, this paper exceptionally adopts two crucial compositions of PET, and eventually gives a unified calculation formula. In order to determine an appropriate threshold, traffic conflict data collected from Guangyuan Road in Guangzhou are analyzed. The results clearly prove that PET <; 0.7 means a serious conflict, 0.7≤ PET <; 1.31 means a general conflict, 1.31≤ PET <; 2.25 means a slight conflict, and PET ≥2.25 means a potential conflict. Finally, 50 groups of PET data and a comparative experiment are collected to demonstrate the effectiveness and reliability of the modified PET model.
Highlights
Despite a great improvement that has been achieved in accident prevention, the severe impact of traffic accidents still exists, along with numerous deaths and economic loss
50 groups of Post Encroachment Time (PET) data are collected to verify the effectiveness of the proposed model
In this paper, the traffic characteristics of the urban road merging area are considered to analyze in detail
Summary
Despite a great improvement that has been achieved in accident prevention, the severe impact of traffic accidents still exists, along with numerous deaths and economic loss. The safety evaluation models of merging areas are mainly based on traffic accident data and traffic conflict technology. Alhajyaseen et al (2014) proposed a new conflict index combined with the change in the total kinetic energy before and after a collision, namely collision angle and PET By using this index, a series of measures were proposed and achieved great success in providing a similar ranking of the different signalized intersections to the ranking, which is based on the number of crashes occurred at each site [37]. It can provide significant assistance to safety management and decision-making of merging area in urban roads, and offer a theoretical basis for a variety of comprehensive intelligent transportation systems It can be used for predicting the safety level of merging behavior under Connected Vehicle Technology (CVT)
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