Urban socioeconomic patterns revealed through morphology of travel routes

The city is a complex system that evolves through its inherent social and economic interactions. Mediating the movements of people and resources, urban street networks o↵er a spatial footprint of these activities; consequently their structural characteristics have been of great interest in the literature. Missing from the analysis is the specific interplay between street structure and its functional usage, i.e the movement patterns of people and resources. To address this limitation, we study the shape of 472,040 spatiotemporally optimized travel routes in the 92 most populated cities in the world. The routes are sampled in a geographically unbiased way such that their properties can be mapped on to each city, with their summary statistics being representative of meso-scale connectivity patterns. To characterize each city’s morphology, we propose a comprehensive metric, inness, that examines the geometric shapes of the routes relative to the city center, presumably a hub of socioeconomic activity. The collective morphology of routes exhibit a directional bias that appears to be influenced by the attractive (or repulsive) forces resulting from congestion, accessibility and travel demand, which of course, relate to various socioeconomic factors. An analysis of the morphological patterns of individual cities reveals structural and socioeconomic commonalities among cities with similar inness patterns, in particular that they cluster into groups that are correlated with their size and putative stage of urban development. Our results lend weight to the insight that levels of urban socioeconomic development are intrinsically tied to increasing physical connectivity and diversity of road hierarchies.