# Reinventing Mobility Paradigms: Flying Car Scenarios and Challenges for Urban Mobility
## 5 Discussion and Conclusions  
The agent model set to simulate the selected case C has provided a preliminary analysis for a possible large use of flying cars in UAM scenarios. As a general comment, the results obtained show that an increasing use of flying cars produces contrasting effects on the ground network depending on \begin{table}
\begin{tabular}{c c c c} \hline \hline  & \multicolumn{2}{c}{**Transportation Networks 6 \(\times\)**} & \\  & \multicolumn{2}{c}{**6 Modules**} & \multicolumn{2}{c}{\(9\times 9\)**Modules**} \\  & \multicolumn{2}{c}{\(\mu\)} & \multicolumn{2}{c}{\(\mu\)} \\ \hline \(S_{0}\) (Baseline/\(O\)/\(D\)) & 0.41 & 0.35 & 0.29 \\ \(S_{1}\) (15\% O/\(D\) increase) & 0.52 & 0.40 & 0.36 \\ \(S_{2}\) (30\% O/\(D\) increase) & 0.75 & 0.52 & 0.48 \\ \(S_{3}\) (45\% O/\(D\) increase) & 0.82 & 0.68 & 0.59 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Simulation results. Figure 6: Simulation results. the network size and the amount of demand. For the latter, an increase in trip demand level generally produces an increase in link traffic flows, which, in turn, produces an increase in travel costs according to a congested network approach. In these conditions, and as known from the literature referring to user equilibrium traffic flow assignment (see, for example, [52; 55]), an agent's path choices will change depending on link travel times, thus producing a traffic flow distribution on the network. The particular feature of the network here is that some of the links, specifically aerial ones, have been considered uncongested--which at a first attempt may be considered reasonable because horizontal lanes at several vertical heights are possible--and then travel times on aerial links do not depend on traffic flows. At the same time, the use of such links is limited to transition nodes, in other words, although travel times on aerial links are generally more convenient because _i_) aerial link speed is greater than ground link speed and _ii_) link travel times do not depend on the amount of traffic on such links, to use them, the transition node must be reached by ground mode. Since the structure of cities has been considered as the current one, flying and ground modes co-exist because individual trip origins and destinations are reached only by ground accesses. As a consequence, not all the trips are suitable for flying legs. In fact, when ground traffic increases and then travel times generally increase, reaching transition nodes to use the aerial links is not necessarily more convenient than using an only ground path for the given _O/D_ pair. In addition, in some traffic conditions, waiting times at the origin are possible, thus increasing the overall travel time. Although limited to this first set of experiments and the hypothesized scenarios, however, two main preliminary comments about the use of individual flying cars in urban contexts can be carried out: (_i_) they are not necessarily more convenient and sustainable than current ground mobility when the demand level is increasing; (_ii_) the potential advantage is linked to the _O/D_ pair distance, the location of transition nodes and demand level. It is worthwhile to note that an increasing level of trip demand may depend on population increase but also on increasing flying car share. In other words, some appealing properties--such as the opportunity to bypass ground congestion--could generate increasing purchases, thus increasing the use of flying cars in future scenarios, which, in turn, would produce an increase in network congestion. Further research is required to better understand how UAM scenarios could be planned, which depends on still open questions linked to key features associated to the possible large use of flying cars, and how sustainable they could be in terms of life quality. A first important step is to set standards and safety/security regulations, both for those on board and those who are overflow.