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Optimising urban passenger transport: Developing a least-cost model based on international comparisons of urban transport costs, transport patterns, land use, infrastructure environment and best practice in public transport

Laube, Felix B. (1998) Optimising urban passenger transport: Developing a least-cost model based on international comparisons of urban transport costs, transport patterns, land use, infrastructure environment and best practice in public transport. PhD thesis, Murdoch University.

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Public policy debate today in the field of urban transport tends to be strongly divided. On the one hand there are those who see private motorised mobility or automobile dependence as a logical expression of growing wealth and as such, virtually unavoidable; the city must be adapted to almost open-ended car use. On the other hand, there are those who see private passenger transport as a major problem in cities for a whole host of reasons; car use should be kept within limits imposed by the capacity of the urban system to deliver livability and ecological integrity. Several issues are prominent in this debate such as what primarily influences a city's transport system - physical characteristics of the city or the economics of transport systems. The relative economic merits of different transport modes are also hotly contested. There are claims that non-automobile modes are discriminated against in the market place by inequitable pricing policies which subsidise private transport, while others argue that private transport is more cost-effective and leads to economic growth and wealth creation. With respect to the role of public transport, one side tends to marginalise it, while the other claims that it has a much bigger role to play in cities. A host of data are brought to bear on both sides of the argument claiming to be authoritative, whereas in fact in most cases direct comparability remains somewhat illusive. Naturally, calls for balance between the two views can be heard which attempt to recognise the advantages and disadvantages of the different modes and to arrive at a point where a socially-optimal balance of transport modes might be struck, and where overall transport costs might be genuinely minimised in a city's economy. Unfortunately, a methodology that might be universally applied in finding such a balance and which would bring more clarity and rigour to the debate, does not appear to exist.

This thesis therefore attempts to develop such a methodology by first asking and providing answers to a series of key questions. These questions relate to transport's position in the economy, its true costs, the extent and nature of competition between different modes, critical land use-transport interactions, the interaction of transport costs with other elements of the city, how these costs can be minimised and the role of public transport in this process. By then hypothesising that in any particular city there exists an optimum modal balance which will minimise transport costs as a function of that city's physical and economic constraints, the thesis sets out to develop a model which would represent an optimal balance of transport modes in any city. Through the use of an extensive theoretical overview, combined with thorough collection and analysis of a massive amount of comparable empirical land use, transport, economic and environmental data on 46 global cities, the thesis succeeds in providing some new insights into the above questions and building the suggested model. It also contributes significantly to overcoming a major problem in this policy debate area; the lack of standardised, comparable urban data across a wide range of city types.

The research isolates what appear to be the key underlying factors which determine the characteristics of the transport system and its overall costs. These factors are primarily physical in nature; by contrast, the key economic factors, such as the cost of driving a car, the cost of using or operating public transport and the gross regional product per capita (or city wealth), do not bear significant relationships with modal split. Through a detailed statistical evaluation of all data collected in this study and a step-by-step model building process, the key factors behind the development of a least-cost transport curve are identified. This curve shows what percentage of total motorised passenger kilometres are required on public transport in order to minimise overall passenger transport costs in any city. These costs are expressed as a percentage of a metropolitan region's gross regional product per capita. Using the results of the statistical analysis, it was found that an effective least-cost model could be developed based on the relationships between urban density and private and public transport use, and thus mode split. In order to translate private and public transport use into cost, the relationships between car ownership and car use, as well as between public transport supply and use were then integrated into the model equation.

This model, despite its present prototype form, yields some potentially significant policy insights. These include:
•the fact that all cities in the study appear to benefit economically from a greater role for public transport; all cities appear to be underprovided with public transport service and thus public transport is underused.
•the critical nature of the relative speed between public and private transport. This has direct implications for their competitive position and thus points to the need for appropriate investment in faster public transport or disinvestment in private transport infrastructure which will give public transport a speed advantage;
•the strong influence of higher urban density in improving public transport use and minimising overall transport costs, revealing the importance of reurbanisation programmes in cities. Low density cities are confirmed as being highest in overall transport costs which is not compensated for by higher levels of income and wealth. This has implications for their global competitiveness.
•the potential of lower private transport costs to negatively affect public transport share, thus offsetting the former's cost savings through increased external costs.
•the importance of internal economic efficiency in public transport systems in contributing to their role in the urban transport system, but not at the expense of service quality.

This least-cost model appears therefore to be worthy of further development and refinement as suggested in the thesis. If this can be done it would provide a very useful and wide-ranging policy tool which could be used to:
•find what modal split between public and private transport is required to minimise overall urban passenger transport costs;
•establish what kind of policies in urban planning, transport planning, infrastructure planning and the setting of transport costs might be required for a city to head towards this more satisfactory position;
•test a range of theoretical changes in various factors to see what happens to the least-cost mode split point (eg increased investment in public or private transport infrastructure (rail or freeways), changes in density, pricing policies or changes in cost structures, for example in the energy sector).
•formulate strategic policy directions and to monitor progress and adequacy of applied policies over time.

In terms of the greater role for public transport suggested by the modelling work, the thesis explores ways of optimising the overall performance of urban passenger transport through improved public transport delivery. This work suggests that it is very important to distinguish between the commercial and social optimum in public transport and that only at the social optimum does public transport reach its full potential in a city's economic well-being. This mostly means running public transport systems with an operating result which is not as good as when public transport is commercially optimised. And in operational terms, better exploitation of public transport's potential would appear possible through the use of a coordinated and integrated public transport which employs: (a) time-pulse transfer networks; (b) pulsed, supply-based scheduling; (c) bulk, prepurchase oriented system-wide fare systems; (d) regional cooperation.

Overall, the thesis points to a host of possible future research endeavours and policy applications which have the potential to improve the quality of urban transport decision-making and outcomes.

Item Type: Thesis (PhD)
Murdoch Affiliation(s): Division of Social Sciences, Humanities and Education
Notes: Note to the author: If you would like to make your thesis openly available on Murdoch University Library's Research Repository, please contact: Thank you.
Supervisor(s): Kenworthy, Jeff
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