Spatial Econometric Analysis Of Urban Expansion According To Residential Density Profile In The District Of Tunis

Urban expansion of the city of Tunis, source of distortion of inter-zones balance between housing supply and employment, does only increase daily mobility and increases pressure on public transportation in terms of traffic, on transportation infrastructure in terms of congestion and on the environment in terms of pollution. This study tried to detect urban expansion patterns through estimating the gradient of a population density function in relation to distance from the center, whose shape is inspired by the standard models of the urban economy. Negative and significant signs of density gradients for the periods 1984, 1994 and 2004 indicate that the city of Tunis is more compact around its centre, and knows an exceptional expansion of its peripheries. A deeper analysis of density using spline regression techniques showed that the city can be divided into three rings, a central ring characterized by lower density gradient synonymous with progressive urban expansion, a ring containing the suburbs marked by a compact dynamic in the first decade slowed down in the second decade, and a suburban ring characterized by a progressive compacting process around classic suburban centres.