Global trends toward urban street-network sprawl

Area of Science:

• Urban Planning
• Geographic Information Science
• Network Analysis

Background:

• Street-network sprawl is a key aspect of urban development.
• Measuring sprawl through local street connectivity provides novel insights.
• Global urbanization trends necessitate understanding network evolution.

Purpose of the Study:

• To present a global time series of street-network sprawl.
• To analyze changes in multidimensional street connectivity over time.
• To identify trends and persistence in urban street network disconnectedness.

Main Methods:

• Utilized high-resolution OpenStreetMap data.
• Integrated satellite-derived urbanization time series.
• Computed and validated multidimensional street connectivity measures using graph theory and geographic concepts.
• Calculated the street-network disconnectedness index (SNDi) globally.

Main Results:

• Street networks in new developments in 90% of populous countries became less connected since 1975.
• Only 29% of countries showed improving street connectivity trends since 2000.
• A near doubling in the frequency of high-circuity street networks (e.g., gated communities) was observed.
• Identified persistence in street-network sprawl, with low connectivity correlating with historical patterns.

Conclusions:

• Street-network sprawl is a persistent global phenomenon.
• Path-dependent processes influence urban network development.
• Prioritizing road building in new and expanding cities is crucial for sustainable urban development.