MODELLING THE ACCESSIBILITY TO PUBLIC LOCAL TRANSPORT FOR INCREASING THE EFFICIENCY AND THE EFFECTIVENESS OF THE SERVICE. THE CASE STUDY OF ROCCELLA AREA IN PALERMO

This paper suggests a methodology to assess, through quantitative indicators, the public transport based accessibility inside an urban area. Such indicators derive from two functions, one called “activity function”, allowing for the presence of generators and attractors of mobility and another termed the “impedance function”, measuring the generalized cost of public transport journeys. The proposed method was tested and applied to a zone on the outskirts of Palermo (capital of the Sicilian Region), to evaluate the effects of a new tram line, which is under construction and will be activated by the end of 2012. The study shows that such a line is not sufficient to enhance significantly the accessibility of this zone except nearby the tramway. Therefore, to reach a high level of accessibility in the whole study area minimising, at the same time, the public transport operating costs, it could be better to plan an integrated system in which the tram service is supported by new bus lines or novel routes of the existing ones. Today, many European cities face the shortage of public funds, which raises the issue of efficiency for local policy actions. Given the above, we intend to provide the local town authorities with methodological tools to improve public transport performance and consequently accessibility, under severe budget constraints, by the re-organization of the service and a better exploitation of existing facilities.