A Methodology to Evaluate a Toll-Ring Implementation in Terms of Metropolitan Equity. The Case of Madrid Metropolitan Area

In accordance with the European Union (EU) policy, which favors tolling systems based on the calculation of marginal social costs, Spain is studying the implementation of an interurban road pricing scheme. In particular, a main result derived from the model developed in order to estimate the external costs produced by the road users of the Spanish interurban road network suggests that a road pricing scheme based on the congestion costs makes sense only if applied to a few number of metropolitan highways, where it can be used to manage the car travel demand. Therefore, the implementation of a toll road on the metropolitan highways raises questions about its socio-economic effects. This paper focuses mainly its analysis on the results of the simulation of a toll-ring applied to one of the more congested rings of the Madrid Metropolitan Area, the M40. The results are analyzed in terms of efficiency (gains in terms of travel time) and equity (who pays for this time savings). Finally, the results of the implementation of such a toll-ring pricing policy show a clearly increasing level of socio-spatial inequalities. In fact, when the users have a viable road alternative, the burden of the toll-ring is equally distributed, but if not, the burden of a toll-ring has greater effects on people of low or modest income.