With increasing data availability due to intelligent transportation systems (ITS) deployments, methods for assessing and reporting traffic characteristics and conditions have begun to shift. While previous Level of Service (LOS) methods were developed for use with limited data, we now have the power to develop and test the use of actual performance measures. Important measures like average speed, travel time, and intersection delay can be used for performance monitoring of the transportation system. On freeways, such performance measures are often estimated directly using data from inductive loop detectors (e.g., speed, occupancy, vehicle counts). For arterials with numerous signalized intersections, performance measures are more challenging due to more complicated traffic control and many origins and destinations. However, within signalized networks, travel time, speed, and other key performance measures can be obtained both directly and indirectly from sources such as automatic vehicle location (AVL) data. In this paper, we demonstrate how AVL data can be used to characterize the performance of an arterial. First, we extract data from the bus dispatch system (BDS) of the Tri- County Metropolitan Transit District (TriMet), the transit provider for Portland, Oregon. Then, the performance characteristics as described by bus travel on an arterial are compared with ground truth data collected by probe vehicles equipped with global positioning systems (GPS) sensors traveling with normal (non-transit) traffic on the same arterial on the same days. Comparisons are drawn between the two methods and some conclusions are drawn regarding the utility of the transit AVL data.
Samenvatting