Center for Activity Systems Analysis

The fundamental principle of intelligent transportation systems is to match the complexity of travel demands with advanced supply-side analysis, evaluation, management and control strategies. A fundamental limitation is the lack of basic knowledge of travel demands at the network level. Modeling and sensor technology is primarily limited to aggregate parameters or micro-simulations based on aggregate distributions of behavior. Global positioning systems (GPS) are one of several available technologies that allow individual vehicle trajectories to be recorded and analyzed. Potential applications of GPS are implementation in probe vehicles to deliver real-time performance data to complement loop and other sensor data and implementation in vehicles from sampled households to record route choice behavior. A flexible GPS-based data collection unit has been designed which incorporates GPS, data logging capabilities, two-way wireless communications and a user interface in an embedded system that eliminates (or minimizes) driver interaction. This paper describes the design and initial implementation tests of this unit.