## 2 Materials and Methods  
As indicated, the main objective of the present study was to analyze whether any of the basic operating design variables of an urban bus network play a significant role in the recovery of users in the post-COVID-19 scenario in the city of Almeria, as an example of a complex medium-sized city. In the analysis, only variables intrinsic to the urban bus operating, both qualitative and quantitative, were considered, discarding other broad-spectrum variables external to the service, which public managers have fewer possibilities to tackle in the short term. To analyze the level of correlation between the variables selected, a two-dimension MCA was performed by using SPSS v.29 and XLSTAT2019 software. In addition, the individual lineal correlation between the operating variables and the percentage of recovered passengers in each bus line in 2022 as compared to 2019 was analyzed. More complex non-lineal or multilinear models were discarded due to the exploratory nature of the study and the limitation of the data, which come only from a medium urban transport service. The city of Almeria, located in the south of Spain, with a population of 199,237 inhabitants (2022), is especially appropriate to carry out this study, due to the diversity of characteristics in the urban bus lines that provide service within the municipality. Thus, the city has a municipal area of 295.51 km\({}^{2}\) where there are 17 small urban settlements apart from the main city, which concentrates 84% of the population. Population density reaches 11,922 inhabitants/km\({}^{2}\) in the main city (an example of a compact Mediterranean city) and 674 inhabitants/km\({}^{2}\) in the municipality as a whole, showing the diversity in the territory occupation pattern. In addition, an international airport, a state-level port for goods and passengers, the main hospital of the region, as well as a public university with approximately 12,000 students are located in the city. The location of the city at a national and regional level is shown in Figure 1.  
This diversity results in an intrinsically complex UPT network, which allows the authors of this study to analyze the role of very different operating variables, both qualitative and quantitative, with a wide internal range of values, which is crucial in an exploratory study of this nature. The main city is located at the western end of the municipality, which results in long bus lines towards the small urban settlements located to the east. Thus, the urban bus network of Almeria city consists of 16 lines, whose routes are schematically shown in Figure 2 on Google Earth v.7.3.6.9750:  
The evolution in the number of users of the UPT (bus) in the city of Almeria from 2019 to 2022, according to the data provided by the Mobility Area of the City Council, is  
Figure 1: City of Almeria location. Figure 2: Municipal urban bus network area coverage. indicated in Table 1. Only trips on weekdays have been considered, since the particularities during weekends and holidays could bias the results. As can be observed, during 2020, the COVID-19 pandemic drove half of the users to leave the UPT. In 2022, the last year with partial restrictions on UPT (use of masks), the recovery in the number of users compared to 2019 amounted to 78%, similar to other UPT systems [4; 5; 6; 7]. The evolution in the number of users during the 2019-2022 period, disaggregated at bus line level, is reflected in Figure 3.  
As can be observed, three levels of lines according to the number of users can be distinguished. There are seven lines with fewer than 200,000 annual users, eight lines with around 500,000, and one line (L18) with over one million. There is no route pattern explaining the difference in the number of users among lines, even though it is remarkable that L18 connects simultaneously the hospital and the university with the city center.