John W. Dickey

Evaluation of alternative growth patterns in urban systems

Abstract The paper describes the formulation of the general planning model, TOPAZ (Technique for the Optimum Placement of Activities into Zones) and its application to evaluating and optimizing alternative growth patterns in urban systems. TOPAZ identifies an urban system as a set of interacting activities to be allocated to a set of zones to maximize an objective of overall benefit less cost of interaction between activities together with the benefit less cost of establishment of the activities, over a set of time periods. The model takes the form of a non-linear assignment problem with linear constraints, and is solved using iterative linear programming. The model is illustrated by application at a macro level to the evaluation of alternative corridor growth patterns for the city of Melbourne (population 2.4 million) over three time periods, 1970–80–90–2000. Two activities are involved, residential and employment activity, and the interactions consist of work, residential, industrial and commercial trips. The city is divided into forty zones.

Introduction to Techniques

The purpose of this book is to present a set of techniques which have proved valuable in the solution of planning problems in two major areas (1) urban and regional planning and (2) delivery of urban services including location and planning of facilities. Urban and regional planning has taken on increased importance over the last two decades as populations have increased, as migration from rural to urban areas and from inner to outer urban areas has varied along with changes in lifestyle, and as resource shortages, particularly energy, have begun to bite.

A simulation-search technique: An example application for left-turn phasing

A TECHNIQUE IS PRESENTED WHICH COMBINES SIMULATION AND SEARCH PROCEDURES. THE PARTICULAR SITUATION USED FOR AN EXAMPLE CONCERNS DELAYS TO LEFT TURNING AND OPPOSING TRAFFIC AT AN ISOLATED INTERSECTION WHERE THE LEFT TURN GREEN (LTG) AND FULL GREEN (FG) PHASES OF A PRETIMED TRAFFIC SIGNAL CAN BE SET TO ANY DESIRED VALUE. A TIME- ORIENTED SIMULATION IS MADE OF THE ARRIVALS, PROCESSING AND DELAY OF VEHICLES AT THE INTERSECTION FOR ONE LEVEL OF HOURLY ARRIVAL VOLUMES AND FOR ONE SETTING OF THE LTG AND FG PHASE. THEREAFTER, NEW SETTINGS ARE DERIVED BASED ON THE MEASURED DELAYS. THIS PROCESS CONTINUES UNTIL OPTIMUM SETTINGS HAVE BEEN ESTABLISHED. THE SEARCH PROCEDURE UTILIZED IS MULTIDIMENSIONAL AND STOCHASTIC IN NATURE AND RECOGNIZES A LEVEL OF RESOLUTION WITHIN WHICH NO MEASUREABLE DIFFERENCES IN A CONTROL VARIABLE CAN BE DETECTED. THE PROCEDURE ALSO TAKES ADVANTAGE OF ANY PRIOR KNOWLEDGE ON THE PART OF THE USER IN ORDER TO ESTABLISH A STARTING POINT. RESULTS INDICATED THAT MINIMUM DELAY SETTINGS CAN BE FOUND RATHER QUICKLY WITH THE TECHNIQUE EVEN IF THE STARTING POINT IS POORLY SITUATED. /AUTHOR/

A Summary Evaluation

Lack of proper management of resources is one of the major problems facing the world in this decade, and possibly in the distant future. Fossil fuels and other mineral deposits which have taken millions of years to accumulate are facing exhaustion in time periods now under present planning consideration. The impact of these conditions on the planning of facilities must be taken into account if they are not to be rendered obsolete before they even come into existence. Transport systems, urban development, and building complexes all face critical appraisal or reappraisal in this light.

Early Warning Systems for Urban Policy-Making and Planning

Aside from their educational value, models are supposed to be beneficial to the decision-making process. There are, as we well know, many reasons why this cannot be so. Both technical and political decision-makers often are guided by factors other than those embodied in the model. These might include, for instance, past decisions made by these people or agreements made to trade votes in exchange for each other’s favourite projects. Under these circumstances there is relatively little contribution that a model can make to influence the “proper” decision.

The use of Modelling in the Planning Process

The record of useful application of models in urban and regional planning does not look very impressive if judged from recent literature. The rather spectacular failures of some large scale urban models are featured in review articles and some harsh statements have been made: They are established without a single successful demonstration, they are tried everywhere and they do not work anywhere. They require theory that no one has and data no one can get. All claim to enhance societal learning, but none contain operative mechanisms for benefiting from their own mistakes (13.1).

Recent Advances Incorporating Diversity, Entropy, Utility, and Information Theory

The preceding chapters describe the development of TOPAZ as a second generation urban model and its use at various planning levels. Its further development as a third generation model with enhanced capabilities for forecasting and explanation, as well as planning and evaluation, is now described.

Growth Corridor Studies

The preceding chapter highlighted a variety of sensitivity studies that can be carried out using TOPAZ. This chapter centers on more in-depth investigations of the impact of constraining growth to selected corridors in the Melbourne area. In 1971 the Melbourne and Metropolitan Board of Works (MMBW), the authority responsible for planning the future development of the city, produced a report (3.1) recommending that any outward extension of the city be contained within eight growth corridors radiating from the fringe of the existing development.

Water Supply Catchment Planning

TOPAZ can be applied to a variety of water-related problems in addition to those concerned with the costs of urban and regional level services. As an example, in fitting with the larger geographical context in the preceding chapter, it would be possible to use TOPAZ for helping to plan an overall regional water system, including the location of water storage spaces, power plants, and irrigation areas, and the selection of the capacities and times of development of each (9.1 and 9.2) .

Commercial Building Planning

Planners and architects have long recognized the need to integrate buildings into the surrounding environment and relate them to each other, and in a similar manner to integrate the activities within each building with the building form. The relationships among activities, and between the activities and the building, have mostly been expressed in qualitative terms in the past, but now it is possible to increase the level of quantitative information and analyze it to aid the planner and architect in the design of buildings and building complexes.