Summary:
Transport sustainability can be either based on technological changes or on management strategies aimed to set up traffic condition reducing the fuel consumption and emissions levels. Speed limits either optional or compulsory belong to this category of management policies. The introduction in Europe of the new emission directives concerning emissions generated by transport, especially in terms of NOx and PM pollutants has prompted in some countries the introduction of such management policies which the main objective of getting the emissions’ levels below the established thresholds. The introduction of such policies raises concerns because of the social impacts making recommendable a technical advice to the authorities before their implementation. A sound technical advice must be supported by a suitable tool, to take into account the dynamics of the traffic process and fully disaggregated models accounting for the driving cycles. Instantaneous emissions models combined with dynamic traffic models to estimate and forecast traffic estates should be used. This paper presents an impact study for Barcelona before the implementation of a compulsory 80Km/h speed limit in the accesses to the city. The paper proposes a methodology based on a microscopic simulation model enhanced with the ad hoc instantaneous emission model and presents the results of the study and the acceptable agreement with the observed results one year later after the implementation of the policy.