以期望值觀點推導路口衝突量

Intersection Traffic Conflicts Derived by Expected Values

安全、經濟及效率一直是交通工程師努力之目標。針對安全目標而言，當車輛通過路口時，易與其他車流產生分流、併流及交叉等衝突行為，故車輛於道路系統中行進時，均會因不同之交織行為而產生不同之衝突或肇事。因此車輛在行經平面交叉路口時，每一部車都將面臨到危險或衝突，所以，如何計算出路口之衝突量，乃為路口安全分析上重要課題，且透過衝突量之計算，不但可作為道路規劃者之參考準則，亦可讓用路對於路口之安全性有更深一層之了解。然過去分析路口之衝突時，大都著重於衝突點之計算，並未考量衝突之發生潛在機率、流量大小及車輛位置等因素。因此，本研究乃從期望值之觀點，分別建立交叉、併入及分出之衝突量模式，冀望能藉由此類模式提供交通工程師於比較分析路口安全性及從事事前事後評估工作時之參考。

Safety, economy, and efficiency are the major concerns of trafficengineers. With regard to safety, conflicts may occur in the intersections dueto crossing, merging or diverging of traffic. Therefore, vehicles are likely toface some potential risk when they go through an intersection. It is veryimportant to analyze the possible conflicts at an intersection for road usersand planners. Most previous research efforts were focused on estimation ofconflict points. It is hard to evaluate the exact conflicts at an intersectionby the result of conflict points. This paper investigates relevant factors ofconflicts, such as probability of conflict, flow and vehicle position. Theobjective of this study is to setup the crossing, diverging, and merging modelsbased on expected values. Traffic engineers can evaluate the degree of safety atan intersection by the proposed formulas when they conduct before and afterstudy.