Morfologia urbana, trasporti, energia: indicatori di impatto

Abstract

The mobility plays a very important role for the internal market, employment and, more generally, the citizens’s life quality that takes great advantages from an effective and sustainable transport system. In the last twenty years, mobility has become an ever increasing necessity: the average mobility per capita in Europe, measured in passenger-kilometres per capita, is increased by 7% between 2000 and 2008 and it is expected that in 2050 the passenger-km OECD Europe will double compared to 2000. Furthermore demand for resources and food is continued to grow well beyond the GDP over the past decade (EC, 2011), enhancing thus the freight. The current transport model that responds to this mobility demand, which also includes a large part of trips that could be avoided (McLellan & Marshall, 1998), is based on the dominance of road transport and use of fossil fuels (EC, 2011), both for freight and transport of passengers. As a conseguence this transport model is accountable for 23% of energy consumed in Europe, and about three quarters of which depends on road transport (IPCC, 2007) It is estimated that energy consumption in this sector will increase by around 80% for 2030. In this sector, the energy consumed originates of 96% from oil and its products (IPCC, 2007; EC, 2011; Lerch, 2011). Therefore, the transport sector is responsible for high emissions of CO2 and other climate-altering gases, for the temperature increase and for significant health problems in population directly exposed to oil-derived pollutants(U.S. EPA, 2010). The strong dependence on oil may also have important consequences on the resource supply and mobility of citizens for the next decades (EC, 2011; U.S. Joint Forces Command, 2010). The majority of trips are internal to the urban areas that are affected by this congestion, local air pollution, road accidents and social harms. Finally, urban trips have a major influence on climate change and energy consumption at the global level. Samaniego & Moses (2008) show the similarities existing between cities and organisms. Urban trips are effective if are done through a network representing an ordered configuration of relationships -connectivity-(Capra, 1996) which implies a particular shape, definite structure and one or more specific processes. The characteristics that are observed in organisms today are the result of millions of years of evolution that led to optimized structures that tend to minimize the energy cost for resource allocation thus maximizing their productivity. Therefore, the organisms tend to minimize their degree of entropy. To arrive at a configuration of urban connective tissue that can minimize its level of entropy is first necessary to identify a set of indicators on the basis of which it is possible to characterize the space and make possible dynamic analysis of urban morphology. In this context, the aim of this contribution is to identify a first set of meaningful indicators derived from a comparison of the characteristics of the vascular networks of an organism with the urban connective tissue.