# Reinventing Mobility Paradigms: Flying Car Scenarios and Challenges for Urban Mobility
## 1 Introduction
In most transportation studies, agents have been associated with different entities--such as travelers, vehicles, and signals--to interact in a complex way with other entities and to simulate multifaceted, intelligent behaviors (also adopting machine learning techniques) such as, for instance, human behaviors [22]. Agents have also been exploited for mesoscopic traffic simulations, combining micro and macro aspects [23; 24], and macro simulations (e.g., [25; 26]), although in this case their use appeared limited. Implementing an air urban transportation system is complex because many technical, urban, legal and economic criticisms must still be solved. On one hand, the needs and features of urban air modes have neither been taken into account in the existing urban context (such as requirements for landing and take-off areas), nor in current rules (such as for safety, security and privacy issues related to the possibility for a flying car to pass over or near to buildings). On the other hand, the implications of a UAM transportation system, which results from the interactions between air and ground transport modes, are not yet fully understood. Starting from the above overview, this study wants to explore the potential of air transport mobility in urban contexts in the \"sustainable mobility\" perspective and to answer to the question: \"is this new mobility opportunity overcoming some of the main problems--congestion and increasing travel times--that are considered some of the \"sustainable mobility\" shadow variables?\". In fact, flying vehicles are considered (or offered on the market as) one of the options to reduce travel times to move between origin/destination pairs (then they would contribute to improve life quality). At the same time, they would reduce environmental impacts because of the expected decrease in ground vehicle congestion. This study will analyze from a quantitative point of view to what extent there is evidence for those improvements. Finally, the aim of the paper is neither to analyzes flying vehicle technology in itself, nor to discuss socio-economic implications, potential for inclusion/exclusion, and so on, but to simulate the \"system\" in a holistic perspective where, potentially, different types of vehicles (ground and flying) could be used. To address such issue, the status of the urban transportation network made by both ground and aerial links--where flying and ground vehicles can partially coexist--has been simulated, which is an important planning and management transport activity [27]. UAM scenarios, where flying cars are used in cities in both flying and ground modalities, are explored by using agent-based simulations, the features of which have been designed by considering the main rules and standard behaviors that flying cars should have. Each agent represents a moving object--both flying and ground vehicles. Starting from the recent development of Connected Automated Vehicles (CAVs), and by considering flying cars as a further evolution of CAVs, the hypothesis here is that manned or unmanned flying cars have similar behaviors, because automation has been considered a standard feature of this type of vehicles. The simulation has been addressed to verify which kind of improvement flying cars could represent for urban mobility and whether flying cars could be a sustainable alternative to the current urban scenario. To this aim, a travel time index has been proposed and some test networks, at increasing size, have been designed for a baseline scenario--where only ground vehicles are allowed--and some alternative scenarios--where flying vehicles are allowed in both ground and flying modes. The choice to simulate test networks at increasing size has been made in order to avoid comparing real scenarios, in which the specificity of facilities and network structures may produce distortion effects. Then, the results will provide insights into the possible benefits of flying vehicles for explanatory test cases that are comparable among them and will serve as basis for further studies.