Challenge for Urban Airspace Planners: Considering Horizontal and Vertical Dimensions for Scaled Delivery Operations

Cities are increasingly addressing mobility challenges by restricting road traffic, particularly traditional road vehicles that generate greenhouse gas emissions. As an alternative, unmanned aircraft systems (UASs) are emerging as a promising solution for future mobility, offering fast, quiet, cost-effective and environmentally friendly operations. For last-mile delivery, small drones operating at low altitudes are considered especially promising and are already being deployed in some urban areas. According to the EU Drone Strategy 2.0, drone services could generate a market of €14.5 billion and create 145,000 jobs in Europe by 2030. As this sector is still in its early stages, there is a significant uncertainty about the optimal organisation of urban air traffic. In this paper we present a realistic prognosis of how unmanned traffic over a city will utilise the urban very-low-level airspace and assess it using two concepts of operations, with non-structured or structured airspace, both aiming to facilitate the coexistence of competitors sharing the same urban low level airspace. The two concepts are evaluated with delivery operations at scale for a large and densely populated European city. Results for a normalised scenario of 3500 daily operations show that structured airspace produces more conflicts than non-structured airspace (e.g., 316 vs. 54, respectively), and that only for the non-structured airspace can all conflicts be solved with a simple strategic altitude reassignment (vs. 10% of unresolved conflicts for structured airspace). The artificial organisation of slim urban airspace may limit the scalability of business delivery while not reducing the conflict rate.