The Internalization of External Costs of Motorway: Cases in Spain

As the road traffic especially the freight transport growing, traffic congestion, traffic accident, noise and environmental problems become more and more seriously. But these costs are not all paid by users but society, and also the roads' constructions and maintenances are invested by the government. It is to say there impacts are externalized on the society. So many researchers postulate the "user pay" principle for internalizing external cost and charging the user of transport infrastructures. This paper develops a methodology to evaluate the social costs including internal costs and external costs of roads. Social costs is composed of internal costs and external costs, therein internal costs contains time costs and operation costs, and external cost includes maintenance costs, CO₂ cost, accident cost and noise costs. Road pricing is to internalize the external cost, which is paid by the government. So it is important to evaluate the social costs especially the external cost of roads. Here an evaluation model is made, and then the road network data in Spain are used to validate it. First it is necessary to divide all the roads by the number of lanes and then choose three dimensions (the Flow of Roads, the Proportion of HGV and the Space Speed) as three factors to regroup all types of roads with different lanes in Spain. K-meaning method is used to cluster each type of roads, for every type we choose two typical clustering that one is called the representative clustering, and the other is highlighted clustering to do the analysis. Mathematical software is used to calculate the social cost of four kinds of vehicles: Car, HGV (Heavy Goods Vehicles), LGV (Large Goods Vehicles) and Bus. Finally this research get the conclusion that the Spanish government spends lots of money on the maintenance of Spanish roads, but not so much users are using those roads, the cost for the HGV, LGV and BUS are much higher than the cost of Car especially the maintenance cost and the maintenance cost for HGV is very high. Certainly the result can give some suggestions to the policy of roads pricing in Spain.