There are few doubts about the current necessity of undertaking a deep analysis on what are the present transport tendencies and how planning should assist in the definition of the best strategies and actions to tackle the problems that society is now facing. Conventional planning and assessment methodologies and techniques developed to mitigate transport detrimentalimpacts have analysed observed and projected transport trends and have tried to improve their environmental and social effects, often by ex-post measures. Although this approach has led to an improvement in comparison to previous results, and despite the adoption of new regulations seeking for ex-ante mitigation, it has not led us towards meeting long-term environmental objectives. New, innovative tools and approaches are needed to enhancethe aim of sustainability. One of the most interesting methodological procedures to be followed is called backcasting: Starting from that "desirable" long-term future scenario, a set of actions required to make it viable is identified. The desirable future is defined through the use of criteriawhich can be quantified and have environmental significance. Taking into account the current trends, the actions to be undertaken will then lead usto achieve this situation. The proposed paper is focused on the application of the backcasting principles to an area of special interest due to itsenvironmental sensitivity. Most of the northwest part of the Madrid region is an environmentally protected area under national and European regulations- and the amount of traffic that it supports is expected to rise significantly if current trends continue. The Madrid metropolitan area is a very active territory in terms of economic development, with implications such as urban sprawl, traffic increase, and environmental and social detrimental impacts. In this context, a desirable future for the year 2020 is defined through the use of a set of indicators, including emissions, energy consumption, land take and travel time, which aimed values for 2020 are defined according to the policies, strategies and protocols already in force, translated to the area under study. An estimation of traffic flows throughthe area is developed using the VISUM transport model. Regarding the baseline situation, the model is run with 2004 data from the Regional Transport Authority, including origin/destination and number of trips by private vehicle and public transport, modelling such trips on the existing transport infrastructure. The amount of trips for the year 2020 in the Business AsUsual (BAU) 2020 scenario is calculated from the year 2004 data, expandedby the predicted increase in land take and its use (industrial, residential, commercial) and therefore potential population and origin-destinationsas well as different infrastructure options. In order to know the degree of environmental effects, the indicators mentioned above are calculated for the baseline scenario using VISUM results and the COPERT emission factors for each type of vehicle technology. In addition, an estimation of the likely new vehicle technologies and their emission factors for the year 2020 is also developed, which will be applied to VISUM results for 2020 BAU scenario. Indicators for the BAU scenario will then be compared with those for the desirable scenario in order to assess how distant they are. According to the differences, a set of policy options, measures and combinationsof them will be defined, including technological and demand management options. Their potential contribution to the achievement of the pursued target values will be assessed, aiming at identifying the best combination. For the covering abstract see ITRD E137145.
Abstract