Environmental Costs Account: a base for measuring sustainability in transport plans

Each city need to develop sustainable transport plans according to its future developments. This means identifying the best policy package of transport measures that could produce more sustainable future scenarios: lowest environmental impact, but also better social standards and at minimum cost. To that end, it is necessary to measure the environmental and social costs of each alternative transport mode. This paper proposes a methodology to calculate those costs in different city contexts: city centre and metropolitan suburbs. It provides a measure of the following environmental costs: pollution, noise, green house gasses and land taken. Then the social costs as congestion and accident costs. These two cost categories are calculated for each mean of transport: metro, bus, private car and taxi. The methodology has been applied to Madrid Region through modeling its mobility demand in 2004. The outputs are costs per passenger-km in each mode and Area: city centre and metropolitan ring. Therefore it is possible to assign monetary costs to environmental and social costs of each transport option; for example, car environmental costs are four times higher than buses on average, but it differs a lot from city centre to outskirt areas. Finally, some guidelines can be extracted to develop a more sustainable transport policy for Madrid Region. Assessment of environmental costs in urban areas Achieving sustainable mobility in urban areas means to reconcile environmental protection with social well-being and economic development. These targets include reducing the negative impacts from transport, including pollution, noise and congestion, while ensuring affordable, accessible and safe mobility, without affecting the living conditions of future generations [1, 21]. To measure how sustainable mobility is achieved we need to settle a number of indicators [5]. However, the assessment methods of transport policies more often use time and cost indicators rather than environmental ones [22] The approach adopted to analyze transport sustainability is to develop the socio-environmental account of transport means for each specific city or region [3]. This integrated approach considers all transport externalities in a comparative way and is a good tool for planning taken into account social fairness [15, 18, 19]. We have used these concepts making the travelers transport account of Madrid. In this account, we have worked with social costs like a way for analyzing the sustainable transport. This kind of assessment has been improved over time (decades) by including more factors [6, 7]. Thus, in Europe we can find several transport studies dealing with counts of general social cost or externalities at a national, regional or urban level [23, 25]. In this paper, we show the importance of urban and metropolitan environmental cost among various diverse transports modes. We will analyze the results of the Madrid case study and we will point to guidelines for a more sustainable development in cities. Social transport account: how to measure. Environmental costs and externalities allocation are necessary to calculate the optimum social costs and sound basis to reduce global car mobility in cities [14]. Sustainable mobility is linked to the model for urban development in each city [4, 9, 10, 13]. Suburban sprawl causes trips that are cheaper for user but generate more global mobility and less social welfare. The internalization of externalities can correct this process [26]. To deal with this kind of effects we need to know the social cost of all kind of trips, for each city zone and transport mode [20]. In the transport account presented here, we have used disaggregated data to provide detailed results for different geographical zones which influence the costs of trips: urban and metropolitan. Transport social cost is the cost paid for an individual trip by the whole society. These costs have two components, one is internal and the other external. The cost structure is different for every transport mode, so we can use that cost account for comparing the performance of trips made with different modes. In this study we have taken into account the following modes: urban bus, suburban bus, metro, suburban train, car, taxi, and walking (in Madrid bikes are not representative nowadays). The kind of costs we took into account include: infrastructure, operating cost, travel time, accidents, noise, air pollution, global warming and land taken. We have given special attention to externalities within social cost, although we have not taken into account some externalities such as downstream processes because they are still not significant [25]. Table 1. Costs appraised in the study