基于路段转移采样的最优路径集计算方法

Calculating Multiple Optimal Routes Based on Link-to-link Transition Sampling

为了不计算路段阻抗而获取起点到终点的多条最优路径,提出一种基于路段间转移概率并通过路段转移采样来计算最优路径集的方法(最优路径集路段转移概率法):首先,通过分时段、分区域来获取路段间转移概率,采用时段划分将交通状态随时间变化的影响纳入考虑,利用交通小区代替给定起点和终点,避免了路网中起点与终点数量巨大、特定点对之间数据量不足的问题;然后,基于路段转移采样进行轨迹采样并获取最优路径集。该方法不需计算路段阻抗,对数据要求低,计算简便。案例分析表明:利用最优路径集路段转移概率法得到的计算路径与实际路径的涵盖程度高,区域划分大小对结果影响较小,时段划分可有效反应交通状况。

A link-to-link transition sampling method utilizing the historic data of link-to-link transition probability to obtain the multiple optimal routes between the given origin and destination in a road network(method of link-to-link transition probability for multiple optimal routes)was proposed to avoid the need of calculating the link travel times.Firstly,the link-to-link transition probabilities were calculated with travel data of time and region division.The impacts of traffic conditions were taken into account according to time division.And the problems of the large number of starting points and ending points and the insufficient data of specific point pairs in the road network were avoided by replacing the given starting point and ending point with the traffic zone.And multiple optimal routes were calculated with route sampling based on the link-to-link transition probability.The proposed method demonstrated the advantages of no need to calculate the link travel time,low requirement of data and easy implementation.A case study showed that the optimal routes obtained with the proposed method are much in accordance with the actual optimal routes.The size of traffic zones has minor impacts on the results,and the division of periods can effectively reflect the traffic conditions.