3.0 Shorten distances

3.01. Associate home with work
One of the most important causes generating journeys is getting to work, and this leads to interest in this criterion as a possibility for improving sustainability within the city. As the transport sector is one of the greatest contributors to so-called diffuse contamination (directly related to the climate change question) this should appear in a good part of the legislation, and of course in the guidelines and recommendations. The scarcity of the mentions and general references in guidelines and recommendations leads to the suspicion that this endeavour faces difficulties. However, it is a criterion that should be related to the complexity of land uses (already studied in the previous section) and with the fostering of rented housing. The complexity of the use of land should allow the existence of jobs near homes and a sufficient supply of homes to rent would allow the two elements to be brought closer.

3.02. Establish logistics platforms for distribution in each neighbourhood
The retail selling of products and their distribution on both wholesale and retail levels is one of the outstanding challenges for urban planning. From the viewpoint of the system's sustainability it is fundamental to shorten the distances products and provisions must travel to reach the consumer. Even from the perspective of pure economic efficiency it is urgent to introduce these type of considerations into sustainable urban planning.

3.03. Foster polycentrism
This criterion could be treated as a special case of the foregoing one; however it has specific issues which work against this consideration. The case of fruit and vegetables is a quite symptomatic example. Over time the peri-urban agricultural tradition has been tending to disappear in face of the advance of urbanization to such an extent that city planning did not even consider its continued existence (sometimes it did not even recognize it). However there are many reasons for the need to keep these areas alive and operating, from the complexity they introduce to their contribution to reducing the products' delivery distance. There are also psychological factors, such as bringing the city dweller closer to agriculture and not only to areas of protected nature, controlled to a greater or lesser degree.

3.04. Reduce the infrastructures necessary for the city to function
Above all, but not exclusively, an aim is to reduce the infrastructures necessary for communication. The increase in urban space per inhabitant, which has increased almost geometrically as shown by the multiple studies carried out (see Naredo and Gascó on the Madrid Region), is essentially caused by the increase in the number of roads and the spaces given over to leisure and free time activities. Specifically the square metres destined to infrastructures are relatively straightforward to quantify (there are studies from the beginning of the last century, including those of Unwin in his manual on urbanism) and therefore it does not appear to be very complicated to legislate for both maximums and minimums.

Discussion