To determine origin-destination (OD) data for a transportation system, a processor may receiving passenger statistics collected from a set of data collection devices deployed throughout the transportation system. The processor developing a model representing passenger usage of a portion of the transportation system. The model comprises nodes that each represent a geographical area of the transportation network, and links that represent transportation routes that connect two nodes. The system determines link utilization rates for each of the links by applying the passenger statistics to the model, and it generates an observation report comprising an origin-destination matrix for at least the portion of the transportation system so that the origin-destination matrix comprises the determined link utilization rates.