This thesis work is the result of an internship at Arriva Italia Srl, that is a local public transport company and owns a fleet of about 2500 buses. Specifically, the internship has been carried out in Turin, where the company owns a fleet of about 215 buses. Among the various departments of the company, the section where I operated was the Technical Area, which focuses on vehicle maintenance. To better understand, it could be useful to introduce the definition of maintenance, according to legislation UNI 13306:2018, which states that "Maintenance is the combination of all technical, administrative, and managerial actions, during the life cycle of an entity, intended to maintain it or return it to a state in which it can perform the required function”.