Urban growth along motorways in Switzerland

Urban growth is a key concern for planners as it has considerable ecological impact. In both Switzerland and the European Union this growth has mostly proceeded at the expense of agricultural land. It is not yet, however, well understood what drives this extensive land-use change. This study assesses the influence of proximity to motorway exits on urban growth and analyses urban growth along some of the main motorways in Switzerland. The analysis is based on two data collection campaigns from the Land Use Statistics with a time difference of 12 years. Proximity is measured as the distance from a motorway exit, which we related to changes in the entire urban areas and their subclasses 'Building areas', 'Industrial areas' and 'Transportation areas'. Linear regression revealed a significant distance trend whereby the closer an area lies to a motorway exit, the higher the rate of urban growth. Industrial areas show the strongest distance trend. Further, variance partitioning revealed the exclusive explanatory power of distance from a motorway exit by partialling out two further potential predictors, the previous urban area and the local relief. We found significant effects of distance, e.g. on industrial areas in the Central Plateau and on building areas in the Central Alps. There, we can assume a causal relationship between proximity to motorway exits and urban growth. Regarding ecoregions or urban subclasses, no uniform picture emerged. We thus recommend discussing urban sprawl separately for different areas and subcategories of urban land. (C) 2010 Elsevier B.V. All rights reserved.