Sustainable Urban Transportation: A Model-Based Approach

Transportation and its environmental impacts are a major component of urban environmental management. At the same time, transportation and mobility are an important part or urban economics and the quality of life. To analyse urban transportation and its environmental impacts, a comprehensive, interdisciplinary approach is needed. No single model can cover the range of spatial and temporal scales and processes involved. This leads to a multi-tiered approach and a cascade of models to describe alternative urban development and transportation scenarios and their multi-criteria assessment and comparative analysis. This paper describes the methodology and application examples of SUTRA, Sustainable Urban Transportation (http://www.ess.co.at/SUTRA/) a City of Tomorrow project under the EU Energy, Environment and Sustainable Development Research Programme. The primary objective of SUTRA was to develop a consistent and comprehensive model-based approach and planning methodology for the analysis of urban transportation problems, to support design strategies for sustainable cities. This includes an integration of socio-economic, environmental and technological concepts including the development, integration, and demonstration of simulation tools to improve scenario design, assessment and policy level decision support. Sustainable Urban Transportation K.Fedra 2 of 36 Combining an indicator based approach with simulation models ranging from technoeconomic optimisation to street canyon modelling, used for scenario analysis, socioeconomic and environmental impact assessment, and a web-based public information component, the methodology ranges from awareness building end educational aspects for citizens and stake-holders participating in urban decision making processes to detailed technical modelling and optimisation results for the planning professional. The models employed in SUTRA describe urban development scenarios, their implications for the transportation system, a range of economic and environmental impacts. Special emphasis was given to emissions and ambient air quality, and in consequence, population exposure and public health consequences, and accidents. The models used range in scale from street-canyon models with time horizons in hours, to regional photochemical models considering seasonal patterns, transportation models describing the city and its environs, techno-economic models for long-term city-level or regional technological and energy analysis, that estimate, inter alia, the market penetration of new transportation technologies over 20 to 30 years planning horizons. The links between the models, as well as the initial scenario assumptions and the overall evaluation framework are formulated in terms of indicators. The city case studies of the SUTRA project (Buenos Aires, Gdansk, Genoa, Geneva, Lisbon, Tel Aviv and Thessaloniki) differ widely in terms of culture, environmental conditions, size, economic structure, social composition and demography. The modelling approach developed was tested against this range of cities to ensure general applicability, and at the same time to provide data for a comparative analysis of the scenarios explored. Sustainable Urban Transportation K.Fedra 3 of 36 INTRODUCTION Transportation problems are among the most pressing strategic development problems in many cities, often a major constraint for long-term urban development in general, and very closely related to land development, economic structure, energy policies, and environmental quality. Since all citizens are either enjoying the transportation system or, and often at the same time, suffering from it, it is an important element of the urban quality of life. The problems to be solved are the inefficiency of urban transportation systems and underlying land use patterns, which negatively affect quality of life, economic efficiency, and the environment; the high (and often hidden) costs of urban transportation in both socio-economic and environmental terms; and in particular the environmental consequences both in terms of physical aspects that include land and resource use, ecological aspects, and human health problems. Efficient tools for comprehensive strategic analysis that are directly useful to city administrations are lacking. New strategies for sustainable mobility require well balanced combinations of measures with impacts on • improved land-use/economic development planning; • improved planning, management and use of transport infrastructures and facilities; incorporation of the real costs of both infrastructure and environment in investment policies and decisions and also in user costs; • development of public transport and improvement of its competitive position; continued technical improvement of vehicles and fuels; • incentives for the use of less polluting fuels; promotion of a more environmentally rational use of the private car, including behavioural changes. These problems can only be addressed with a consistent and comprehensive approach and planning methodology that helps to design strategies for sustainable cities. This has to include an integration of socio-economic, environmental and technological concepts including the development, integration, and demonstration of methodologies to improve forecasting, assessment and strategic policy level decision support (Fedra, 2000a,b,c) . No single model can cover the entire range of Sustainable Urban Transportation K.Fedra 4 of 36 processes, and the spatio-temporal scales characterising them, leading to a multitiered approach (Fedra and Haurie, 1999). The alternative of a loosely coupled set of models for scenario analysis, embedded in a common framework of indicators and a multi-criteria assessment methodology was developed in SUTRA. From a technical perspective, the project did develop and apply and common set of indicators for urban sustainability for a baseline analysis, ranking and benchmarking (with a larger set of cities across Europe) that ultimately feeds into a discrete multicriteria assessment and selection mechanism. These indicators, at the same time, provided some of the links, keeping the loosely coupled nested or cascading simulations models employed consistent. The analytical tools include: • Techno-economic analysis and energy systems analysis and modelling using well established modelling approaches such as MARKAL, are used identify and evaluate cost effective transportation scenarios, consistent with the larger economic and technological framework, and estimate the market penetration of new transportation technologies (fleet composition). • Traffic equilibrium modelling was used to evaluate alternative transportation policies, including multi-modal systems, high-occupancy vehicles, park and ride systems, and transportation telematics and their relation to land use, technological development, socio-economic development, and spatial and structural urban development (land use scenarios) in general. • Emission modelling that translate the results of the transportation model such as traffic frequencies and driving conditions together with the fleet composition into the emission used in the air quality models • Air quality modelling is used to translate emission scenarios into ambient air quality estimates, ranging from street canyons to the regional scale, and population exposure both for short-term events and for season and annual time frames. • A fuzzy rule based system was used to estimate public health impacts and the probability and costs of accidents. Sustainable Urban Transportation K.Fedra 5 of 36 • The economic assessment, using classical econometric valuation methods, estimated the full individual and external costs of the alternative development scenarios and their transportation strategies on this basis. • Finally, a discrete multi-criteria method was used for a multi-criteria ranking analysis, with the results compared to a Europe wide city benchmarking exercise.