# Improving the Functional Reliability of an Urban Public Transport Line
## 1 Introduction  
### For a More Attractive Urban Public Transportation  
Since the intensive use of cars by an increasingly large part of the population, the planning of the territory has been unable to integrate the new urban spatial mobility supported by cars. As a result, almost everywhere, large urban agglomerations are faced with the negative effects of excessive car traffic: decreasing the accessibility of places of interest (especially in central areas), loss of street functionality as public spaces for informal communication, air, and noise pollution, degradation of mobility conditions for those who do not use cars (pedestrians, cyclists, public transportation users), and others [1; 2; 3; 4]. The responsibility of the authorities is only partially justified. Moreover, in the most frequent situations, in addition to other specific interventions and with less relevant effects at the global level, the authorities have already offered solutions for spatial movements consistent with the sustainability of life and urban activities by promoting efficient and qualitative public transport. The question that needs to be answered is: \"Why do these better transportation alternatives (which should generate significant migration to the public transport offers) have not always met the expected larger social adhesion?\". Of course, a possible answer would be that the offer of public transportation did not prove attractive enough (even in the hypothesis of services with dedicated tracks that provide average travel speeds higher than their own car's speed). In addition, this is the case even for those who seemed willing to give up their cars [5; 6]. In short, the offered public transportation still does not meet the quality requirements. Even if a synthetic definition of quality, as the totality of attributes that provide maximum satisfaction to the user, is suitable for both a product and a service, we must notethat the differentiation between the quality of a service versus that of a product is necessary. If we examine the attributes of quality, then we find that in the case of service quality, they are more diversified and more sensitive. This involves specific and subtle actions to increase quality or to compensate for the lack of attributes specific to products [7; 8]. All the attributes of the service--intangibility, inseparability, variability, perishability, lack of ownership--are at the origin of the actions through which it is also possible to increase the attractiveness of urban public transport [9]. Some attributes of the service quality are the consequence of strategic decisions regarding the compliance qualities of the resources related to the urban public transportation line (infrastructure, means of transport, materials, energy, human operators). Other attributes are the consequence of tactical decisions that are related to the operating technologies adopted according to the estimated demand. There are also attributes of service derived from operative decisions, those through which the transport operator aims to match the supply with the temporal and spatial variations of the demand or with the disruptive effects affecting the planned supply [10]. Regardless of the decision-making level (strategic, tactical, operative), the manager of a public transportation network of services faces in his actions the difficulty of solving the same problem--the harmonization between productive technical efficiency and commercial efficiency with direct implications in service quality. Productive technical efficiency is defined as the ratio between the performance achieved (measured in vehicles. km, offered in-vehicle places. km, commercial speed, level of use of the active fleet, etc.) and the number of consumed resources (material, human, energetic, financial) that are the subject of maximization in the transport operator's analyses.