Abstract:

In order to further clarify the differences in routing behaviors of different taxis, this paper adopted the method of frequent sequence mining to extract the frequent path between the same OD pairs, construct path sets, and analyze the similar characteristics of path sets from static and dynamic perspectives. By taking the trajectory data of taxis in Xi’an City as the research object, the path set between OD pairs is obtained through grid division and road network matching. Then, the frequent path is redefined, the PrefixSpan evolution algorithm is adopted, and the dynamic threshold and frequency index based on the obtained frequent subsequences are introduced to mine frequent paths. Furthermore, in order to complete the construction of three kinds of effective path sets, the shortest path and other paths are extracted, and the general properties of the constructed path sets are analyzed. Finally, the similarity between two-dimension time series (tracks) on the path is represented as dynamic similarity, and the similarity between one-dimension directed sequences (sections) is represented as static similarity, and the similarity analysis of three types of paths is carried out based on the improved longest common subsequence and dynamic time regularity algorithm. The results show that: (1) the similarity between the frequent path and the shortest path is rather high, meaning that most taxis still choose the road with the lowest travel time but not the shortest path; (2) time and distance are still the main considerations for travelers when choosing a path, but travelers do not completely pursue the shortest time or distance; (3) the calculated dynamic similarity is significantly higher than the static similarity, which means that the two-dimension sequential similarity on the path is higher than the one-dimension shape similarity; and (4) the two proposed methods both possess the highest similarity between the frequent path and the shortest path and the lowest similarity between the shortest path and other paths The consistency of the comparison results indicates that the similarity of the static path can be roughly measured by the that of the dynamic trajectory. The proposed frequent path mining algorithm is of certain reliability. It can provide supports for urban traffic managers with recommend routes and planed roads.

Key words: traffic and transportation engineering, trajectory data, frequent sequence mining, path choice set, similarity characteristic analysis