Future-proofing curb space: An AHP-based prioritization framework for flex zone use cases in the era of autonomous mobility

As autonomous vehicles (AVs) reshape the urban mobility landscape, cities face growing challenges in utilizing surplus road space created by improved traffic efficiency. This study examines the potential of Flex Zone, a dynamic and multifunctional curb space concept, in accommodating emerging mobility demands. While recent frameworks have begun to incorporate future-oriented modes such as AVs, Shared Autonomous Vehicles (SAVs), Urban Air Mobility, and micromobility, a systematic approach to organizing these functions remains limited. To address this, we present a restructured typology of 14 Flex Zone use cases that integrate diverse technologies and operational purposes. Using the Analytic Hierarchy Process (AHP), the study prioritizes this use cases based on their functional relevance. The results indicate that Public Transit Mobility (0.119), Pedestrian Mobility (0.106), and AV Mobility (0.103) are the top mobility priorities, while Designated Special Purpose Spaces (0.108), including emergency response and charging areas, emerged as essential non-mobility components. Preference variations were also observed across time of day, road hierarchy, and land-use contexts. Building on these findings, the study introduces an AHP-based spatial allocation framework that guides the strategic planning and management of curb space in AVs-oriented urban environments.