Levels of Formalisation in Urban Public Transport Systems

The main objective of this paper is to define the level of formalisation of public transport. To achieve this, we review the available literature on the formalisation of public transport and the guidelines for planning, organising, and evaluating public transport. The approach followed consists of the design of advanced search queries, the criterion-based filtering of the scientific documents collected with the help of these queries, and the addition of complementary documents using simple search queries. This made it possible to define the concept of formalisation (the level of formalisation) and to constitute its explanatory factors with the public transport guidelines. The results show that formalisation improves public transport services from informal to formal options. This research recommends that future research should develop a quantitative tool to capture the level of formalisation in public transport and its practical application to case studies.