Institute of Transport Studies, University of Leeds
Abstract
The task of Work Package 10 is to specify the objective functions to be optimised in the project. As set out in the Technical Annex of the project, there are to be two or at most three versions of the objective function. The first one is to reflect economic efficiency objectives. The second one is to reflect concerns about the sustainability of urban transport. A combination of the two may possibly reflect both kinds of objectives and a definite trade-off between them.
There is of course a wide range of objectives of transport policy in urban areas, but most can be grouped under the broad headings of economic efficiency, including economic development, on the one hand, and sustainability, including environment, safety, equity and quality of life, on the other. Therefore, although the objectives of the nine studied cities will inevitably be different, if the objective functions are adequately specified, it should be possible for each of them to find its own transport policy objectives mirrored in either the economic efficiency objective function or the sustainability objective function, or both. To enhance the chances that the optimal policies that we identify in the project will in fact be implemented, an important element of Work Package 10 is to discuss the formulation of the objective functions with the cities, and to secure that the final specification is acceptable to them.
The transport models of the nine cities differ as to what policies can be modelled and what information they produce. These practical limitations will have to be taken into account when formulating the objective functions.
The methods in use to evaluate urban transport policy differ between the cities. For example, cost benefit analyses are not used everywhere, and the effects included in these kinds of analyses and the weights attached to them differ. To take account of that, a disaggregated yet simple form of presentation of the results of applying the objective functions to each particular model run is sought. It will then be possible for each city to relate the results to their usual evaluation methods. Also, each city may use their own values for the discount rate, value of time savings etc. within limits imposed by the needs to compare the results of the different cities.
Summing up, the task of Work Package 10 is to >specify a standard set of objective functions for both economic efficiency and sustainability, which are acceptable to, and can be applied in, all the cities being studied< (Technical Annex, p.4)
