Freight road transports in Europe have expanded significantly in recent years, leading to increased congestion, pollution and accidents. This problem will require the conjunction of many different remedies. The promotion and substitution of transportation modes with less negative effects is one element of the solution. This paper presents results obtained from a detailed geographic information system modeling of the Belgian multimodal freight transport network inserted within the overall trans-European network. The results of a simulation of the flows over the Belgian network in 1995 are outlined, which allows the estimation of some of the costs of several external effects of fright transports. The costs of pollution, congestion, accidents, noise and road damages are estimated at over 2 billion ECU in 1995. The results of a simulation internalizing the corresponding marginal external costs suggest that a road pricing policy integrating these factors could be effective in limiting road congestion, overall pollution as well as the other external effects. External costs savings could amount to about 500 million ECU
