Stage-dependent scaling of travel distance shaped by 3D urban form
Yangzi Che, Guangdong Li, Xiaoping Liu, Libang Ma, Kangning Huang
- Applies a floor-area-weighted 3D mobility-distance metric to 6,582 cities and over 650 million buildings across 173 countries, showing that vertical urban structure can either compress or stretch inferred mobility space
- Finds 3D mobility distances are smaller than 2D estimates in 79% of cities due to vertical intensification, but rapidly urbanizing megacities such as Shanghai and New Delhi exhibit 'volumetric sprawl' where vertical growth exceeds 2D estimates by 9–12%
- Identifies stage-dependent scaling breakpoints at ~2.7 million residents and ~$12,476 per capita, beyond which the mobility-distance scaling exponent declines from 0.52 to 0.36, marking a transition toward more efficient urban organization
- Shows that the mitigation potential of vertical urban form is strongest during early-to-mid development, with marginal gains diminishing in high-income large cities where volumetric distribution and spatial organization become the primary determinants of mobility efficiency