Comparison of operational availability of public city buses by analysis of variance

There are numerous works on availability studies, among others. In [3] a general overview of main strategies and technical steps which should be taken when designing an optimum public transportation system. Operational availability as a characteristic of transportation systems is used for analysis of so-called fast reaction systems in random moments of operations (t), for example air force, emergency medical services, fire brigades or public transportation systems [5]. Analysis of availability of different systems has been researched into by many studies in recent years. Nowadays it is applied in many sectors of the industry, including aircraft and defense sectors as well as power engineering and transportation. In [5] the authors present the possibilities of application of the RAM (Reliability, Availability and Maintainability) model in industry to identify unreliable devices with respect to operation-related frequent failures or requirements. In [23] the authors investigate the dependencies between availability and maintainability of transportation modes and the costs of unplanned breaks and vehicle operation. The authors developed an economically-optimum model of implementation for inspection and technical services that was based on current data on vehicle damage. The study [19] examined several scenarios regarding the reliability of buses and repair service employees’ shift system in a transport company to increase the vehicle’s availability and reduce costs of the whole system regarding its disturbance at vehicle failure. In [18] and [28] the authors present an optimization model of public transportation considering the design of transit routes, selection of modes of transportation and timetables. The study [24] presents a method of designing the availability of technological objects, and in [10] a theory pertaining to semi-Markov processes was used based on the authentic municipal transport system. In [2] the authors identified the object’s aptitude condition, and thus optimal control processes of operation and service of particular objects on the example of public transportation bus engines. In [27] the authors present different methods applied to estimate a functional form between overall quality of service and explanatory variables, including questionnaire items related to satisfaction accessibility (availability, information, time characteristics of service, customer service, comfort, safety, infrastructure and environment). The operational availability index was mainly used for bus schedule reliability and current monitoring of transportation systems, especially vehicle punctuality [3, 4, 26] however, it was not often used to control quality management systems and maintenance of a given make of a vehicle. The municipal transport company should assure a continuous monitoring on maintenance process in terms of current availability of used fleet. Resting on this assumption, the authors of the paper conducted studies on operational availability of buses of the selected makes from Joanna RymARz Andrzej NiewczAs Aneta KRzyżAK