Method for Estimating Population OD Matrix Based on Probe Vehicles

Origin-Destination (OD) has always been a concern in obtaining accurate link traffic volume, because it is one of the major inputs to the travel demand forecasting procedure. This paper examines a new approach for estimating static OD using Radio Frequency Identification (RFID) sensors embedded in probe vehicles. More specifically, sample OD based on RFID and route information were used for deriving static OD set. This type of method allows for relative ease in data collection for large scale areas. However, data collected by probe vehicles do not represent the entire traffic on the links, because the number of probe vehicles is limited in practice. Thus, the traffic data collected from probe vehicles are a partial OD matrix, although vehicles can be tracked from origin to destination. In this regard, a sample OD can be expanded to a population OD matrix through sampling ratio. Sampling ratios are then specified to minimize the difference between assigned and observed link flows. The proposed algorithm has performed successfully with an example network and an actual site in Jeju, Korea.