A traffic forecasting system configured to forecast a travel time of a route is disclosed. The traffic forecasting system includes a model-training module, a model-selecting module and a forecasting module. The model-training module builds multiple candidate models. Each of the candidate models corresponds to one of a plurality of road section and one of a plurality of mathematical models. The model-selecting module selects an estimated model corresponding to the road section from the candidate models matching the road sections of the route. The forecasting module calculates estimated vehicle speeds of each road section according to the estimated models of each road section of the route. The model-selecting module selects one of the candidate models corresponding to the road section with the smallest error as the estimated model of the road section.
