Intelligent Transportation Systems

Intelligent Transportation Systems (ITS) have generated considerable enthusiasm in the transportation community as a potential means to improve roadway safety, reduce congestion, enhance the mobility of people and goods, and reduce energy consumption and vehicle emissions. In order to estimate these potential benefits, new and improved analytical techniques and simulation models are being developed for ITS. In terms of environmental effects, the University of California, Riverside, College of Engineering-Center for Environmental Research and Technology (CE-CERT) has developed a...

This study examines the usefulness of complementing accelerometry-based physical activity measurement with spatial data from portable global positioning system (GPS) units to determine where physical activity occurs. Methods: First, using the geographic distribution of data points and Bland–Altman plots, we examined GPS units’ validity and interunit reliability by measuring the distance to a geodetic point. We also assessed interunit reliability by comparing GPS data collected in three built environment contexts. Second, we conducted a pilot study in which 35 participants wore GPS units...

This report contains an evaluation of the sensing techniques and implementation issues of magnetic sensing as a position reference system. The field patterns of sample magnetic markers were first measured to illustrate the basic characteristics of such systems. Several sensing approaches were explained and compared with regard to their functioning principles and sensitivity to measurement variations. Three particular algorithms were discussed with illustrations of respective mapping methods. Robustness and sensitivity of the sensing methods, when subject to signal noises and parameter...

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 which allow individual vehicle trajectories to be recorded and analyzed. Potential...