Understanding the Spatial Accessibility Index for Innovative Air Mobility

With the ImAFUSA Project concluding on 28/2/2026, the following post was written by Future Needs to provide an overview of their work and results in the project. See also this post on their work on IAM and Welfare.

As cities prepare for the arrival of Innovative Air Mobility (IAM), a key challenge is how to assess and enhance equitable spatial accessibility for IAM infrastructure, ensuring vertiports connect effectively with ground transport for broad societal benefits.

As cities prepare for the arrival of Innovative Air Mobility (IAM), a key challenge is assessing and enhancing equitable spatial accessibility for infrastructure. This requires a deep focus on multimodality; since lower-income populations often lack access to private vehicles, the utility of a vertiport depends entirely on its integration with affordable public transit. The Accessibility Index developed within the ImAFUSA project by Future Needs addresses this by evaluating the connectivity between IAM hubs and ground transport, primarily focusing on passenger drones. By ensuring vertiports are reachable via bus or rail rather than just walking or driving, the Index identifies and mitigates socio-economic spatial segregation, transforming IAM from an exclusive luxury into a functional component of a fair, city-wide mobility network.

Why is this important?

Although accessibility metrics exist in traditional transport planning, they do not reflect the distinctive characteristics of aerial mobility. For the general public to justify the cost of Innovative Air Mobility (IAM), trips must solve significant transportation pain points by targeting high-social-value destinations rather than acting as a "one-way" street exclusively for wealthy business districts. True accessibility leverages passenger IAM to connect affordable long-distance commuter satellites (50–100 km away) and disadvantaged outlying neighborhoods to primary job-rich corridors in under 20 minutes. Furthermore, passenger IAM is essential for overcoming regional transit "dead zones" where geographical barriers turn short 15-mile distances into grueling 90-minute commutes. For example, in Istanbul, air taxis crossing the Bosphorus could reduce a 60-minute bridge bottleneck into a 4-minute flight. Passenger IAM could also bridge the "rail gap" between main international gateways and secondary regional hubs, a use case piloted during the Olympic Games of 2024 between Paris Charles de Gaulle and Le Bourget. Finally, this tailored accessibility ensures reliable transit to specialized social amenities, such as stadiums or campuses, during peak events when ground traffic is completely paralyzed.

Future Needs wanted this index to fill a gap by offering an assessment specifically tailored to IAM conditions. Methodologically, the Accessibility Index combines two pillars:

1. A travel-time model, which estimates how long it takes residents to reach the nearest vertiport, considering distance, available modes, and the structure of the ground network.

2. A population-to-jobs ratio (PJR) index, which highlights whether an area is primarily residential, job-rich, or balanced. This affects demand patterns and appropriate UAM service design.

These components produce a single accessibility measure that can be compared across neighbourhoods, cities, or alternative development scenarios.

Instead of assuming equal access across the city, the above examine the real conditions that shape everyday mobility:

• the time required to travel to the nearest vertiport,

• the availability and quality of first/last-mile transport modes,

• the distance from key service points,

• the balance between population and employment in the area

• and broader questions of social equity.

Together, these elements provide a realistic picture of whether IAM is likely to become a widely accessible mobility option or one that reinforces existing inequalities.

The indicator draws on the broader ImAFUSA framework and aligns with the socio-economic assessment tools described in the Concept Outline, including the welfare analysis that links accessibility to productivity and real estate dynamics.

Insights from the Accessibility Index

Within ImAFUSA we have generated several important insights. If not proactively addressed, accessibility disparities in IAM may become more pronounced than those observed in traditional transport systems. Among the factors shaping user adoption, ground access time emerges as a decisive element in determining whether IAM services are realistically viable for the public. Moreover, vertiport placement has the potential to shape local development patterns and influence real estate values, thereby linking accessibility considerations directly to the broader welfare impacts evaluated through the IAM Welfare Tool.

“Our aim with the spatial accessibility index is to make the IAM implementation planning process transparent and evidence-based leading to equitable choices for cities and beyond.” - Anna Palaiologk CEO of Future Needs. 

The index reduces investment risk by showing where real demand is likely to emerge. It also helps cities align IAM deployment with Sustainable Urban Mobility Planning principles and with the ImAFUSA project goal of linking U-space capacity to social, environmental, and economic outcomes.

Ultimately, the Accessibility Index enables cities to move from the abstract promise of aerial mobility to a grounded, equitable deployment strategy. It helps ensure that IAM goes from technological innovation to a coherent component of urban mobility that strengthens connectivity, reduces inequalities, and contributes to sustainable development.