In this study, a modeling of vehicular loads in a fully congested traffic stream state on urban expressway networks is presented. The statistical analysis of randomly spacevaring vehicular loads is performed by using the simulation technique and the observed data on traffic streams, provided by the Hanshin Expressway Public Corporation. The parametric analysis for the statistical nature of vehicular loads is done for the various cases of the traffic stream conditions. To demonstrate the effectiveness of the present model, the probabilistic characteristics of the response of a continuous two-span girder to random vehicular loads are calculated numerically by using the correlation theory of random processes and compared with the simulation results.