UBC Theses and Dissertations
Nodular metropolitan concept transportation aspects. Shahani, Ashok Gurmukhdas
Rapid urbanization is one of the major problems facing the more developed nations' of the world today. With technology making great advances and the needs and values of the people changing rapidly, elements of the cities are becoming obsolete and there is need to expand and build anew; bigger, better, and more beautiful cities. To do this, new and better planning tools need to be developed to understand urban structure and intelligently guide public investment decisions. One of the important aspects is transportation and the impact that changes in land use or the transportation system have on the total travel requirements of the city. Prof. George C. Hemmens, Associate Professor of Planning, University of North Carolina, in a paper "Experiments in Urban Form and Structure" proposed a linear programming model to determine the minimum travel requirements of alternate landuse patterns. He takes as given alternate distributions among sub-regions of an hypothetical urban area of the following urban elements: work place, residence, alternate transportation systems, and an allocation rule which minimizes the total travel time between each residence and work place and a shopping place. One of his main conclusions was that alternate transportation systems do not effect the relative efficiency of alternate landuse patterns. The hypothesis of this thesis is that alternate transportation systems do effect the relative efficiency of alternate landuse patterns. Two sets of experiments were conducted, with some modifications to Prof. Hemmens model, the results of which substantiate the proposed hypothesis. The first set of experiments, using a geometrically non-symmetric road network and a one mode transport system, indicate the relative efficiency of alternate landuse patterns remains constant regardless of the level of service or the geometric pattern of the transportation network. For the second set of experiments two modes of transport and modal split factors for the sub-regions were introduced. It is found that the relative efficiency of the alternate landuse patterns now varies with the level of service, the type, and the pattern of the transportation system. Thus there is just one transportation system most suitable for a given landuse pattern. In general, the concentric ring with dispersed work and shopping (R2C2W2) pattern was found to be most efficient i.e. for a weak commercial and work core the travel requirements were smaller in magnitude than for a stronger core and that changes in the commercial pattern had a greater impact on travel time than similar changes in the work pattern. Also, there exists a trade off between landuse and transportation i.e. landuse changes can be substituted for improvements in the transportation system, or visa versa, to achieve the same desired end result. Because of the simplistic assumptions made, the hypothetical data used, and certain other limitations of the model, the validity of some of the conclusions may be questionable. But, if the results can be taken as conclusive, they are of great significance for planning. Time and locational priorities for all major renewal and new construction activity could be guided by the requirements of the R2C2W2 pattern. The highest priority being given to the restructuring of the commercial pattern and the lowest to the restructuring of the residential pattern. The model could also be used to determine changes in the travel requirements due to the construction of a new shopping center or a new freeway. This thesis is part of a group study dealing with a concept of urban growth and development; the "Nodular Metropolitan Concept." The results of the study substantiate that the "Nodular" pattern of urban structure (which by definition is analogous to the R2C2W2 pattern) has the highest efficiency i.e. the least travel requirements.
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