## 1 Introduction
### State of the Art  
Therefore, it is necessary to analyse mobility in more depth. It is becoming one of the fundamental areas of study within rural and urban areas and is considered an important aspect for the improvement of sustainability in the territory, because, among other reasons, it has as a priority objective the reduction of emissions caused by motorised means of transport [14; 15]. In addition to limited mobility needs in compact urban centres, a change towards sustainable models of existing mobility flows is also necessary, as both rural and urban areas share territorial dynamics that generate daily pendular movements of population between them [16; 17]. For this purpose, many cities have for years been developing measures to promote modal shifts from motor vehicles to sustainable modes of transport [18; 19], with the objective of reducing the ecological, socio-demographic and economic impact on the territories that delimit them [20]. Therefore, it is of paramount importance to start implementing sustainable mobility strategies that are coordinated with supra-municipal authorities, so that sustainable mobility policies can reach the territory beyond the limits of the central municipalities [21]. One of the current challenges is to analyse daily mobility in the areas associated with larger population centres, so that by using data processing techniques it is possible to establish a mobility follow-up of the population in order to evaluate the viability, impact and efficiency of the measures to be implemented [22; 23]. As a result of the COVID-19 pandemic, activity in urban and rural areas came to a complete standstill during the first months of the year 2020, from March to May. In this situation, the different restrictions to prevent citizens from becoming infected meant that no travel of any kind took place, except for that carried out for health reasons [24; 25; 26]. In this way, urban and inter-urban mobility was significantly affected, with journeys being significantly reduced. Public transport [27; 28; 29] suffered a greater impact, as it was initially associated with increased exposure to COVID-19 infection. This caused an increase in the use of individual modes of travel, in which it was estimated that exposure to COVID-19 infection was drastically reduced, leading to the predominant use of bicycles, electric bicycles, personal mobility vehicles (PMVs), as well as a preference for walking [30; 31]. In order to limit commuting as much as possible, teleworking began to be introduced to avoid commuting to the workplace. In addition, learning and the use of new technologies led to an increase in e-learning and online shopping and with the aim of reducing the need to travel to work [32; 33]. This set a precedent and changed the mentality of both public authorities and citizens, focusing attention on providing as many spaces as possible with the basic needs to be able to carry out this type of activity. Thus, on the one hand, the implementation of new technologies in rural areas was prioritised, with the intention that citizens would be able to avoid travelling for work, leisure and shopping purposes. The aim was to bring new facilities to these areas that would allow them to develop socioeconomically and demographically [34]. Sustainable modes of transport (walking, cycling, Personal Mobility Vehicles (PMVs) and public transport) must become the basis for the development of alternative mobility in Spanish municipalities. With this premise, this type of mobility must be encouraged by promoting the use of bicycles and PMVs with the implementation of infrastructure that guarantees the safety of these means of transport [12; 35; 36]. Therefore, quality services must be established to motivate the population to use these modes of travel to free cities from motorised vehicles [37]. At the same time, the safety of bicycle users and PMVs are essential for raising awareness of the use of these transport modes [38; 39].