The useful/sustainable design public transport services is a crucial issue that may affect both the economy of a territory and the social inclusion of its inhabitants. Indeed, the transport accessibility of residences, firms and commercial activities is one of the main driver that influence the localization choices and the local and extra-urban public transport services assumes a central role within this point of view. Furthermore, the recent economic crisis that has struck Europe has even more limited the funds available for public services, including the transport sector. For example, in some Italian regions, a significant funds reduction was observed producing a consequent reduction in public services offered. In this critical context, the rational design of the public transport services become a fundamental activity strictly correlated with the available funds. In the literature, there are numerous studies that focused on the design of transit systems, usually considering only technical aspects of the problem (e.g. user costs and benefits, operator costs). Only few studies also considered social impacts (e.g. externalities). Starting from these considerations, the paper proposes an original methodology for designing the local public transport services through a rational decision-making process with stakeholder engagement. The proposed methodology combines both technical aspects of the problem and social and political issues, also considering the equity in the funds allocation, aiming in obtaining a design solution accepted from the whole community. The proposed methodology consists in different interconnected activities with some loops (retroactions): • analysis of the legislative and planning framework; • identification of mobility needs; • analysis of current transport supply and related supply model; • criteria definition for choosing the best public transport services to implement; • analysis of the current scenario and identification of its main critical issues; • project (design) scenario identification; • public engagement (stakeholder engagement) on all the pervious activities; • formal approval of the design scenario and its application. The first step consists in analysing all the national/local laws and regulations which influence and limit the feasible solutions of the problem (design scenarios). Likewise, previous or hierarchically superior plans may define boundaries or obligate directions to the design solution (plan). The second phase consists in estimating the transport demand in term of all-modes origin-destination matrices, representing the average number of users (for each transport mode) which travels from an origin o to a destination d. These matrices are also referred to different time periods, such as, peak hours, off-peak hours, working day, pre-holiday or holiday. Considering all transport modes available in the study area, it is possible to estimate both the current travel demand (e.g. users that currently travel by public transport) but also the potential demand, that could be captured from new public transport services (e.g. deviated from non-sustainable transport modes). The analysis of current transport supply allows determining, for each origin-destination pair and for each time interval, all available transport modes and the corresponding transport performances in terms of, for example, average travel time, waiting time and monetary costs. All these attributes are used for defining an ad-hoc mathematical model (supply model) useful for simulating the multimodal transportation system. Just before the analysis of the current scenario, it is necessary to fix a priori some rules for determining the optimal operating interval of the different kinds of public transport services to be implemented. Indeed, it is possible to consider: • public transport services with fixed routes and fixed frequencies, generally indicated as ordinary services; • public transport services with fixed routes and variable frequencies, generally indicated as specific services; • public transport services with variable routes and variable frequencies, generally indicated as Dial-a-Ride services. The next phase consists in simulating the interaction between demand and supply, to obtain the user flows on the different elements of the transportation supply. In this phase, it is possible to identify both the “high-demand corridors”, where the current and potential demand is significant, and the “low-demand corridors”, where the traditional public transport services are not useful. Following these phases, it is possible to build the first proposal of the design scenario (plan), which has to be submitted to the stakeholders’ approval. Hence, an iterative process begins between plan proposals and stakeholders’ observation which has to come to convergence using observations’ acceptance, observations’ rejection and/or observations’ mediation (i.e. alternative proposals). Each iteration requires a new formulation of the plan proposal. When the plan has satisfied all stakeholders’ requirements, it is formally approved by the administration and may be applied. To better underline the applicability, the strengths and the weaknesses of the proposed methodology, it was applied to a real case study consisting in the design of the local public transport plan of the Foggia Province in south of Italy. The application results show how the design solution identified was participated and supported by planners, politicians and stakeholders involved.
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