Wide-Area, Four-Dimensional, Real-Time Interactive Transportation System Visualization

personnel and the traveling public. These two groups have long since needed one cohesive place by which to visualize, analyze, and interact with all of these data. Twodimensional “traffic maps” and more sophisticated geographic information system (GIS) databases have become popular means to visualize much of the data; however, typically these systems are capable of only two-dimensional data representations, which can be limiting. Some newer GIS databases can visualize 3-D data, but they are usually slow in rendering and do not currently provide the kind of real-time interaction that is necessary in a dynamic traffic management system. A usability analysis study conducted by the University of Virginia’s Smart Travel Laboratory on dynamic transportation system condition maps noted that “there are numerous examples of functionally deficient [visualization] systems now in use throughout the world that do not meet the needs of users” (1). In 2005 the University of Maryland published a paper in which a basic prototyped 4-D system was created to interact with TMC data sets and devices (2); however, the first prototype was extremely basic and did not incorporate many of the functions necessary to accurately show all necessary data elements that TMCs typically require to function properly. Furthermore, the prototype system was not designed to be scaled to incorporate data for areas larger than the Washington, D.C., metropolitan area. The purpose of this research was to develop a more comprehensive, real-time, interactive, four-dimensional (4-D) visualization system that can be used by TMCs for operations and control and by traveler information systems to communicate traffic conditions to the public. The prototype system is capable of rendering the entire Earth. The globe is modeled fully; however, only real-time data that encompass the major roads monitored by the Washington, D.C.; Northern Virginia; and Maryland TMCs have been included in this paper. As additional realtime data and aerial photography become available, the system can easily expand to incorporate it. This research effort develops the framework around which other states will be able to integrate data into the system to create their own interactive 4-D visualization system.