Currently, there is not a homogeneous Road Pricing policy in Spain. Rather, various roads are tolled, though not in a uniform way and only taking into account financial considerations. For this reason, in this article we propose a Road Pricing policy to implement in the interurban Spanish road network. After identifying the various external costs derived from road traffic, we establish a toll structure that allows internalizing the externalities generated by the road users. In addition, we consider different future scenarios depending on the type of links of the road network and the type of vehicles affected by the Road Pricing strategy. Finally, through a series of simulations we assess the effects that the different levels of the Road Pricing fulfillment have on the traffic flow.