The rapid increase in the number of vehicles equipped with GPS devices has resulted in using automatic vehicle location (AVL) data as probes to identify traffic flow status as well as route travel speed on a very fine spatial-temporal scale. However, these traffic monitoring approaches heavily rely on the widely distributed probe vehicles in the network and the high frequency of these probe samples, which are rarely implemented in the real world. This study aims to analyze the applicability of providing accurate traffic flow information from four types of low-frequency AVL data. Each data source is applied for speed estimation to develop guidelines on GPS data requirements for travel speed estimation. First, the probe sample size of each data source on each target corridor is studied to reveal the road segments that have the potential for speed estimation, along with the GPS sampling frequency of each data source. Second, the impact of probe vehicle types, sample sizes, and GPS sampling frequency is analyzed. This study offers guidance in using GPS data to conduct speed estimation in different scenarios, which can be further implemented in a prototype software tool for estimating the real-time travel speed. This study has shown the applicability for speed estimation from four types of GPS data, where the transit bus GPS data provides the best mean speed estimation. The speed estimation results are compared with loop detector data on a test road segment to evaluate its accuracy. The comparison results show that given the current GPS data sample size and updating frequency, the transit bus GPS data can provide a reasonably accurate estimation of the traffic flow speed with a mean absolute speed difference of 6.96 km/h.

配备GPS设备的车辆数量的快速增长已导致使用自动车辆定位（AVL）数据作为探针来识别交通流状态以及非常精细的时空尺度上的路线行驶速度。但是，这些流量监控方法严重依赖于网络中分布广泛的探测车和这些探测样本的高频，而这在现实世界中很少实现。这项研究旨在分析从四种类型的低频AVL数据提供准确的交通流信息的适用性。每个数据源都用于速度估计，以制定有关GPS数据要求的准则，以进行旅行速度估计。第一，研究了每个目标走廊上每个数据源的探针样本大小，以揭示具有速度估计潜力的路段，以及每个数据源的GPS采样频率。其次，分析了探测车类型，样本数量和GPS采样频率的影响。这项研究为使用GPS数据在不同情况下进行速度估算提供了指导，可以在用于估算实时行进速度的原型软件工具中进一步实施该指导。这项研究显示了从四种类型的GPS数据进行速度估计的适用性，其中公交GPS数据提供了最佳的平均速度估计。将速度估算结果与测试路段上的环路检测器数据进行比较，以评估其准确性。