The State of the Streets: Measurements of Connectivity in the Atlas of Urban Expansion

Relatively little is known about the spatial organization of streets and roads in the world’s cities, the differences that exist across cities, or the differences that have emerged within cities over time. This chapter explores evidence from the Atlas of Urban Expansion – 2016 Edition, to investigate these questions, focusing on measures of road capacity and road connectivity. The analysis is based on a 200-city sample that was selected to represent the universe of 4231 cities with populations of 100,000 or more in 2010. Road network measurements were taken using an intra-urban sampling framework based on a Halton sequence of quasi-random analysis sites. Data was generated using manual digitization of satellite imagery, producing robust metrics but not resulting in complete land use or street maps of cities. Results show that street networks are becoming less orderly over time as newly developed areas of cities have narrower streets, fewer four-way intersections, and less access to arterial roads.