Prototype for Data Fusion Using Stationary and Mobile Data

Arterial performance measurement is a critical issue for transportation system management, traveler information, and real-time situation-aware routing. In many urban areas current information on freeway conditions is available, appropriately given the large amount of travel that occurs on these facilities. However, because nearly 40% of the vehicle miles traveled in the United States occur on arterials, there is a need to provide similar information that can be used not only by travelers but also by traffic engineers and managers. Because many arterials are equipped with actuated traffic signals, the use of already installed sensors has been explored as one source of traffic volume, occupancy, or speed data to inform an arterial performance system. Coupled with this, there is a potential to exploit the availability of mobile probe geolocation data from sources such as automatic vehicle location systems for fleets of buses or taxis, or from cellular phone or other Global Positioning System-type devices. To demonstrate the potential value of fusing data from fixed and mobile surveillance systems toward improved arterial performance reporting, this paper describes the results of a case study from Portland, Oregon, that extracted improved arterial performance measures by combining data from traffic signal system detectors and from buses acting as probe vehicles. In particular, graphical techniques are developed that trace the boundaries of the congested regime in time and space along an arterial corridor. The paper includes recommendations for expanding the techniques to other corridors, using higher resolution, real-time transit location data, and online implementation of an arterial travel time information system.