Mobility energetic balance frames spatial configuration of cities
Urban spatial configurations emerge as the result of interactions between citizens' activities, movements and the landscape. Topography forms part of the physical settings through which mobility occurs, influencing movement energetic requirements. Using road networks, elevation data and mobility flows inferred from geolocated records, we define a simplified comparative measure of movement energy and test how it changes when the observed urban configuration is translated, rotated or rescaled within its topographic setting while mobility demand is held fixed. Across 56 cities, observed configurations consistently show lower movement energy requirements than most of the alternative configurations examined. This recurrent pattern reveals a measurable relationship between topography and urban spatial organization and is compatible with cumulative adaptation among urban structure, mobility and terrain. These findings add an energetic dimension to our understanding of how topography relates to urban spatial organization and provide an empirical basis for considering terrain-related movement requirements when evaluating future urban growth and densification.