UBC Theses and Dissertations
An analytical methodology for short run urban transportation policy questions Culham, Thomas Elwood
The purpose of this paper was to develop an analytical framework to answer short range policy questions. This type of framework is needed because until recently most models dealt with long range capital investment decisions while many urban transportation problems may be solved through low capital cost policy decisions. The literature indicated that equilibrium techniques were essential in providing solutions to short run policy questions. The features of equilibrium theory in general were examined. The theory was then discussed in terms of an application. It was found that the equilibrium state may be obtained through a direct or indirect modelling approach. The direct approach utilizes a single modelling step while the indirect approach utilizes several sub-models. The state of the art is such that it appeared that the sequential indirect approach was the best method to use. A computer modelling framework was developed which included modifications and additions to a system produced at the University of British Columbia. The purpose of the U.B.C. system was to provide detailed analysis of traffic movements over localized traffic networks. The modelling contributions of this paper were the detailed description of the transit user through his trip from origin to destination and the assembly of an automobile assignment model, parking allocation model, transit assignment model and an auto-transit demand model into an equilibrium framework. The new system was tested on a small network. It produced "reasonable results". Reasonable in this case implied: (1) that any changes in service levels or parking costs will result in shifts of demand in the appropriate direction and; (2) that changes in demand will be in proportion to the change in level of service and vice versa. Two parking policies were analysed. The first policy approximated the case where a municipality decides to increase the rates in its own parking lots. Prices were increased on one out of four lots in the test network. The second policy approximated the case where the government is able to levy a tax on all parking lots. Prices were increased on all lots in the test network. The outcome produced by the model confirmed the experience with parking price increases; that is, for parking policies to be effective in reducing congestion, it is necessary to control all parking spaces in the C.B.D.. A number of recommendations arose from the analysis of the results from the test network. It was recommended that further tests be carried out on a more realistic network, and that a set of refinements and sensitivity tests be made on some of the sub-models in the system. In general the model appeared to be sensitive to changes in attributes of transportation alternatives. The development of this system was a step to fill the gap in the armoury of analytical tools. Further work and research may show it to' be useful in practical applications.
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