Travel Time Collection and Traffic Monitoring Via GPS Technologies

Recently, GPS (Global Positioning System) technologies have been increasingly used in various applications of transportation planning and operations. When combined with GIS (geographic information systems), GPS data can be matched with spatial map features such as highways and roads for monitoring traffic conditions on those links. As one such application, GISTT (GPS-GIS integrated system for travel time surveys) was developed. GISTT collects and analyses traffic conditions of links by monitoring speed of probe vehicle(s) and then estimates travel time data both in static and dynamic modes. The static mode refers to the case of offline processing of GPS data from previously dispatched GPS-equipped vehicles to specified road links. The dynamic mode refers to the real time monitoring of speed on the links using a GPS-wireless Internet-equipped probe vehicle. GISTT is tested in various field tests and the results are found to be promising. Furthermore, the GISTT is to be extended by incorporating more complex dynamic algorithms to provide reliable real time traffic conditions. This paper sets a framework of the extended GISTT that contains algorithm to monitor traffic conditions by processing massive data from multiple GPS probes or GPS-enabled-cell-phones in real time. The algorithm involves identifying the traveling mode based on patterns found in relatively short time frame