In urban areas, the existence of traffic signals affects the traffic flowand link travel time accordingly and the densely existing physical intersections inevitably impose a dense node-link scheme for ATIS applications. In ATIS setting, however, the dense and true-to-life node-link representation (in digital map) scheme sometimes has to endure longer processing timefor travel time estimation and forecasting and this causes time lag whichhinder more proper services. The purpose of this paper is to suggest an efficient link aggregation (or representation) scheme for collecting GPS-based travel times and for distributing them in a proper manner. The efficient design is also related with the number of traffic probes and there is trade-off relationship between the reliability of travel time and the required number of probes. In other words, as link length gets longer, the errors associated with link travel times and number of needed probes is decreasing. Considering those, as a tentative outcome, average 1.1 km (2 links) aggregation scheme has been identified as optimal link length for collecting GPS based travel time in Seoul urban area while meeting the required minimum probe number. The proposed node-link design can shed light on the applications in other urban areas while not losing the reliability of the collected travel times based on GPS and meeting the requirement expressed asthe number of probes. For the covering abstract see E134653.
Abstract