Behavioural Models to Assess Urban Air Mobility (UAM) Services

In recent years, the Urban Air Mobility (UAM) concept has been receiving increasing attention as a new aerial mode of transport for passengers in urban areas. This popularity surge is largely attributed to advances in electric battery technology, enabling the development of new light aerial vehicles known as electric Vertical Take-Off and Landing (eVTOL) aircraft. Major vehicle manufacturers like Joby Aviation, Airbus, Volocopter, and Lilium are in competition to bring advanced eVTOL technologies to market for commercially operating UAM services. Meanwhile, national, and regional administrative and political bodies are preparing roadmaps for the sustainable adoption of UAM. Despite several worldwide announcements of upcoming UAM service launches between 2024 and 2026, uncertainty remains about the financial sustainability of possible use cases (e.g., airport shuttles, city-taxis, or inter-city services), particularly during the initial stages when demand may not be substantial due to relatively high tariffs that are not affordable for all. Additionally, there is uncertainty about public perception of low-altitude, short-range flights for daily travel purposes. User adoption of UAM services should not therefore be taken for granted, considering the significant role of transport demand in the overall sustainability of the UAM system. Will new aerial urban services experience massive adoption, or will they remain confined to niches? Additionally, what will be the user profile that chooses them most for their travels? In attempting to address these questions, the scientific literature on UAM demand analysis has primarily focused on UAM demand forecasting without distinguishing between different use cases. Moreover, there is still a lack of knowledge regarding the distinctive traits characterizing potential UAM users, as most studies only focus on the level of service (i.e., times and costs) and socio-economic factors affecting choices. This research aims to bridge up these gaps by comparatively analysing users’ approach towards different UAM services (i.e., airport shuttles, city-taxis, or inter-city services), shedding light on individuals’ latent traits influencing choices, such as personal attitudes. The goal is to provide policy recommendations for the development of a sustainable UAM ecosystem. The methodological approach adopted in this research combines discrete choice models, traditionally used for demand behavioural studies, with psychometric and statistical techniques for measuring attitudes and inferring individuals' latent factors. Furthermore, it integrates estimated models into a transport demand-supply interaction simulation tool to forecast passenger mode choices, including different UAM services, while adopting a scenario planning approach. The application is related to the Milan metropolitan area (Italy), where a large-scale revealed and stated preference survey campaign has been conducted. Research findings indicate that users tend to value UAM for airport access/egress travels more than for other urban trips. In fact, they are willing to pay approximately 50% more for the airport shuttle services, and approximately 35% more for business travels compared to other purposes. This suggests that the most financially sustainable UAM services will likely be airport shuttle connections to and from central business districts. Findings are confirmed by the transport demand-supply simulations related to the analysed case study: the probability of choosing UAM airport shuttles ranges from 2% to 5%, depending on the level of service of competing modal alternatives on the specific origin-destination pair, making them more attractive than other UAM services with a lower probability of being chosen (ranging from 1% to 3%). Focusing instead on the potential passenger profile, the results show significant differences in relation to various UAM services. The profile of potential users of airport shuttle services is the high-income businessman travelling occasionally. For other types of services instead, personal latent traits such as attitudes toward technological advances and perceived safety standards of eVTOL aircraft play a significant role in the adoption of new aerial transport solutions.