Urban Spatial Development Research Articles

Central dimensions in a sustainable urban development

AbstractSeveral dimensions of urban form and spatial urban development are discussed in the light of the main criteria of a sustainable development. If a sustainable development is to be achieved, it is necessary to avoid further urban sprawl. Low density, dispersed cities can hardly be energy efficient unless their inhabitants renounce the freedoms of choice characterizing today's cities with respect to job market opportunities, services and cultural events. However, a strategy for more compact cities should be cautious so that it does not decimate important green areas within the city, and localities of unfavourable microclimatic conditions should not be selected for residential construction. Planning for sustainability must be oriented towards long‐term and global goals, but should not rely solely on technical and instrumental rationality. A broad spectrum of planning strategies should be used, contingent on the concrete planning situation.

Land Use Issues of the 1980s

Land use and development patterns are the result of a complex interaction of demographic trends, economic circumstances, and social attitudes. Technological advancements in areas such as transportation and construction, and the availability and cost of key natural resources, including land, fresh water, and energy, also have a profound impact on urban spatial patterns. Consequently, the determinants of urban spatial form are dramatically different today from the forces that acted to shape American cities in the past. In order for land use controls to be effective, regulations on the use of land must keep abreast of changes in the factors affecting the demand for land. Zoning ordinances, subdivision regulations, and building codes have drawn criticism in recent years from land use planners, developers, environmentalists, and others involved in or concerned with the land use planning process. The myriad problems associated with the rapid growth and expansion of suburbia and, more recently, of exurbia, have been answered with traditional land regulatory mechanisms that have had only mixed success. How have controls been adapted to meet the demands of increasingly complex development patterns? How successful have these modifications been in achieving more efficient spatial configurations and less costly building practices? These issues are the subject of the readings that have been gathered together by James H. Carr and Edward E. Duensing. Beginning with factors affecting land use demand, this volume presents an analysis of current state-of-the-art land use controls, reviews the shortcomings of the current land regulatory system, and suggests certain modifications to improve urban spatial development patterns. The concluding chapters discuss land use issues for future consideration.

Urban spatial development with durable but replaceable capital

The theory of urban spatial development, until recently, has been primarily a static theory of economic equilibrium. The models of Alonso [l], Mills [6] and Muth [7] determine a complete spatial equilibrium between the supply and demand for urban land. The study of growth or change in such models, therefore, has been limited exclusively to comparative statics, Wheaton [8]. It should be clear that the central, and in many respects unrealistic assumption of such models, is that housing capital is neither physically nor economically durable. Without durability, there is no opportunity cost to old capital, no barrier to change, and no history to an urban area. Within such a framework, a common set of conclusions emerges, regarding urban spatial structure. Residential density, and the price per unit of land, decline monotonically from the location of employment. A greater population results in higher density at all locations, while increases in income or decreases in the cost of travel create a more steeply sloped density (and price) gradient. In the last few years, there has been a growing awareness that the equilibrium portrayed by such models does not correctly reflect the process of urban development. Theoretical papers by Anas [2, 31 and Brueckner [4], and an empirical model by Harrison and Kain [5] develop an alternative theory of urban spatial development-in which the process of growth is explicitly modeled and in which capital is completely durable. In their models, the spatial development of cities occurs incrementally over time in successive rings from the center of employment outwards. The development of each ring is done with myopic foresight and is therefore determined exclusively by market conditions at the time of development. Once built,

The Impact of Decentralization on the Journey-to-Work and Pollution

The aim of this paper is to examine the relationship between urban spatial development, the journey to work, and central city air quality. Using a twostep model, we examine the effects of population/employment dispersion on auto work trip generation and the impact of trip making density on central city pollution. The results suggest that: (1) both population and job dispersal play a significant role in determining the spatial variation in trip making activity; (2) dispersal will, ceteris paribus, reduce travel activity affecting the central city and consequently mobile source pollution; and (3) the ultimate impact on dispersion may be small.

Peut-on tirer un enseignement des essais français de modélisation du développement spatial urbain ?

French models of spatial urban development ; ; In France, land use models have not been used as direct tools for transportation planning or moreover, master plan elaboration. However, the author tries to show that they are not without interest : they provide materials to put in question the efficiency of the French guidance system to spatial growth of cities. First this can be shown by looking at several results, which suggese evidence of inefficiency in the process. Second this can be more deeply analysed by reviewing the various economie agent behaviors that is to say : developers, households, landowners and the public authorities. All of that leads to think that the land use process has to be made more responsive and more flexible without changing the bulk of enforce-ments which already exists, but also without enlarging it this could be attained by a direct action upon actor rules of behavior.