The landscapes in Switzerland have been massively altered by increasing urban sprawl. Between 1885 and 2010, urban sprawl increased by 557 percent. It increased especially strong between 1960 and 1980 during the period of large-scale suburbanization and again more recently in 2002 to 2010. This trend can also be observed in individual municipalities and cantons. Urban sprawl is alarmingly spreading from the Midland to the alpine valleys. Spatial planning has not been able to stop the increase in urban sprawl to this day.
The awareness of the many negative impacts of urban sprawl on the landscape and on different areas of life has grown considerably in recent years. In order to discuss the problem on a quantitative basis, however, methods and data have been missing so far, which would have allowed for a comparison of sprawl between different regions of Switzerland. This has changed only recently due to the implementation of the Weighted Urban Proliferation WUP method (or in German: Messmethode der gewichteten Zersiedelung Z). In order to measure the degree of urban sprawl, the sole indication of the size of the settlement area is not sufficient. The spatial distribution of the settlements and population density must also be taken into account. For example, the degree of urban sprawl WUP (or Z) can be quantitatively described as a combination of the measured values of the proportion of built-up areas PBA, the degree of urban dispersion DIS, and the land uptake per person LUP (or in German: Flächeninanspruchnahme FI pro Person).
A quantitative assessment of urban sprawl also allows for establishing reference values, such as targets, limits, and warning values, on the basis of the values of Z for Switzerland, its cantons, and municipalities. Such values depend on the anticipated population development, as the number of inhabitants and jobs is considered in the calculation of the urban sprawl values. Correspondingly, this book proposes reference values for the high and the intermediate population scenarios of the Federal Statistical Office FSO.
Based on these reference values, legal requirements can be developed. These act as a reliable framework for all spatial planning actors, create legal certainty, and can end the detrimental competition between the municipalities for jobs, tax revenues, and residents. The USM-tool, which is also outlined in this book, and the proposed guidelines can help municipalities and cantons to measure urban sprawl in a quantitative manner and to develop targeted measures to limit urban sprawl. With historical portraits we show how selected municipalities and cantons were able to control sprawl within their territory in the past decades.