Traffic congestion and air pollution continue to be serious concerns, especially in large cities, and going forward, this is not sustainable. Urban transport around the world is facing challenges, such as air pollution and inefficient use of resources, that often inhibit economic development. Simply building more roads cannot address such challenges. There is a need to integrate the urban infrastructure through smart connectivity. Smart mobility, as a vital cornerstone of a smart city, will potentially reduce traffic jams, commuting times, and road crashes and create an opportunity for passengers to customize their journeys. In fact, planning smart mobility solutions is among the top challenges for large cities around the world. It involves a set of deliberate actions backed by sophisticated technologies. The different elements and dimensions that characterize smart mobility are investigated to depict the overall picture surrounding the smart mobility domain. Additionally, the trends, opportunities, and threats inherent to smart mobility are addressed. There are four segments of smart mobility that are highlighted in this paper: intelligent transport systems, open data, big data analytics, and citizen engagement. These segments are all inter-related and play a crucial role in the successful implementation of smart mobility.

The COVID-19 pandemic has had a significant impact on almost all the Sustainable Development Goals (SDGs), leaving no country unaffected. It has caused a shift in political agendas, but also in lines of research. At the same time, the world is trying to make the transition to a more sustainable economic model. The research objectives of this paper are to explore the impact of COVID-19 on the fulfilment of the SDGs with regard to the research of the scientific community, and to analyze the presence of the Circular Economy (CE) in the literature. To this end, this research applies bibliometric analysis and a systematic review of the literature, using VOSviewer for data visualization. Five clusters were detected and grouped according to the three dimensions of sustainability. The extent of the effects of the health, economic and social crisis resulting from the pandemic, in addition to the climate crisis, is still uncertain, but it seems clear that the main issues are inefficient waste management, supply chain issues, adaptation to online education and energy concerns. The CE has been part of the solution to this crisis, and it is seen as an ideal model to be promoted based on the opportunities detected.

A sustainable city must be a safe place for its inhabitants when walking, with the absence of fear of crime being one of its main attributes. Although perceived insecurity is one of the main deterrents of walking activity, this relationship requires some clarification in environments which are walkable and safe, with low crime rates. This article contributes to the evidence for the influence of perceived security on walking activity and, as a novel aspect, also analyzes the effects of perceived security on walking as the preferred travel mode. In order to study this relationship, we use a method that combines non-linear principal component analysis (NLPCA) and a logit model (LM). The data are taken from a survey of university students carried out in the city of Granada. Results show that gender and perceived security have a greater effect on the choice of walking as the preferred travel mode, while location factors have significantly more weight in the explanation of the choice of walking as the most usual travel mode. These findings may be extended to other urban areas and can be of use for the implementation of urban policies aimed at designing the built environment to develop more sustainable cities.

En este estudio se analizan los hechos que explican la insostenibilidad ambiental y social del actual modelo de movilidad urbana, junto con las externalidades negativas que provoca el transporte, utilizándose para ello datos estadísticos y aportaciones teóricas recientes. Igualmente, se exponen algunos de los principios que deben regir un modelo de movilidad urbana sostenible, uno de los grandes retos para las ciudades del siglo xxi si se desea mantener o mejorar la calidad de vida de las ciudades medias y grandes.