## 5 Conclusions and Discussion  
This study was carried out in order to analyze the micro-mobility of passengers regarding the difference between the space occupied by passengers with and without reduced mobility when boarding or alighting the train through an experimental approach using a tracking system to obtain the position of each passenger in a controlled environment. Based on the results, it can be concluded that a passenger with reduced mobility uses up to 80% more space than a person without reduced mobility when waiting to board the train. When passengers walk, this space increases due to the need to move their legs and arms, which is also reported in [2; 3; 4]. Boarding passengers use a smaller space compared with alighting passengers. This statistical difference is because passengers alighting could move through the platform to exit the mock-up; however, boarding passengers were restricted to the layout of the train by physical design features such as train doors and a hall entrance layout, which could affect the interaction of passengers [36]. The space occupied by passengers was represented by polygons rather than ellipses, making it more complex to parameterize. As reported in [12; 13], under normal conditions, space can be represented by an ellipse; however, in the case of passengers with reduced mobility, this is represented as a polygon without a standardized shape. For example, in the case of the elderly passenger, in each of the repetitions of the experiments, it was possible to perceive that he was afraid of boarding the train through the center of the platform, as most passengers did. In fact, the elderly passenger at the moment prior to boarding the train tended to stay behind or at the side of the mass of users who boarded the train. Considering the differences in the space used by each passenger, the type of passenger who required the most space was the one who used a param, reaching 1.70 m\({}^{2}\)/pass. This leads us to think that for similar examples of personal occupation (e.g., people with a suitcase, a guide dog, or a cane, or those accompanied by a child, etc. ), there could be a pattern that determines that the area needed to move varies proportionally to the difference in the occupied area. This type of study could lead to the investigation of the congestion at the platform and generate extra preferential waiting areas based on the study of passengers with reduced mobility on metro station platforms. In addition, it is urged to generate greater visibility of the waiting areas, to redesign the space, and to generate more markings or signs at key points to warn the population or guide traffic to relevant areas. It is also proposed to generate campaigns to educate users using the information screens in metro stations. In addition, greater control at peak hours, making use of waiting areas, is needed. Finally, access to these areas through separators or special entrance areas prior to moving to the platform needs to be improved in stations. The analysis presented here is also relevant because, in extraordinary situations, such as the one experienced in connection with the COVID-19 pandemic, the measurement of occupied space turns out to be important for the management of this type of crisis. This also reveals the need to develop a culture in national public transport that improves the way users behave, as this would make it easier consider passengers with reduced mobility and to respect intimate spaces, thus reducing the stress caused by the feeling of overcrowding, as reported in [15; 16; 21; 22]. Regarding future lines of research, it would be interesting to carry out more experiments to study boarding and alighting simultaneously (e.g., passengers alighting who interact with those who are boarding the train). Furthermore, this same study should be replicated based on the current operating conditions of metro stations, that is, of a higher occupational density (e.g., 6 passengers/m\({}^{2}\)). Conceptualization, S.S. and T.F. ; methodology, S.S. and T.F. ; software, S.S. and P.G.