An Analysis of Urban Codes Evolution - A Case of Shiraz, Iran

Urban codes, in terms of zoning ordinance, are the executive mechanism of urban development projects. Over the last century, the evolution of zoning codes, from the formation of functional-based codes to the emergence of form-based codes and hybrid approach, have represented a growing interest in the qualitative dimensions of built environment. The investigations show that the changes from function to building forms is in parallel with the implementation of a model based on humanized and sustainable urbanization. In this research, four qualitative criteria of functional flexibility; form predictability; the facilitation and predictability of issuing building permit; and transparency and readability of the form-based codes were selected to review the evolution of codes due to the expected positive outcomes of form-based codes. Aiming at explaining the need for change in the quality dimensions of urban codes, and through inspecting documents, and by applying a comparative-analytical approach, Shiraz urban codes were examined via three master and detailed plans prepared in the years 1972, 1995 and 2014. The results represents over a period of 40 years, developments in design codes have been in line with developments in the zoning system in terms of functional flexibility. However, these codes have some shortcomings regarding the form predictability; the facilitation and predictability of building permit; transparency and readability. Nonetheless, due to the spatial structure of the functional zoning system in the 2014 detailed plan and its appropriate flexibility, there is a potential to prepare the form-based zoning in order to improve the above qualitative criteria.