AN ALGORITHM FOR CALCULATING DYNAMIC LINK TRAVEL TIMES USING GPS AND DIGITAL ROAD MAP

Facing the needs of dynamic traffic information such as travel time, this article attempts to describe a procedure of collecting dynamic link travel times of urban streets using GPS (Global Positioning System) and GIS (Geographical Information System). As a first step of this, a brief review of travel time measuring practices have been made, with a special emphasis on the derivation of link travel times. The major impetus of this research is to use the floating, or 'idle' GPS-equipped probes whose original missions are not to gather link travel times from the beginning. Rather than this their missions are quite specific such as to be dispatched promptly on demand (using the automatic vehicle location technology) for delivering passengers. The wireless data telecommunication technology has been adopted in between GPS and GIS (1:25,000 scale) database to send local GPS data to central GIS database. In the course of this, the WGS 84 oriented GPS data have been converted for the Transverse Mercator oriented GIS database for map matching. An algorithm based on Oracle query has been developed for transaction of GPS data to link travel times. The proposed algorithm has been tested with actual field data, proving that the errors lie within the 10%. With this result, it is expected that the idle GPS sources can be a good asset for link travel time derivation. Some discussion and future research agenda have also been suggested along with the conclusion. For the covering abstract see IRRD E102946.

Language

  • English

Subject/Index Terms

Filing Info

  • Accession Number: 00780893
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • ISBN: 89-950073-2-X
  • Files: ITRD
  • Created Date: Jan 7 2000 12:00AM