Road network evolution in the urban and rural United States since 1900

We examine a key component of human settlements mediating pollution and congestion, as well as economic development: roads and their expansion in cities, towns, and villages. Our analysis of road networks in more than 850 US cities and rural counties since 1900 reveals significant variations in the structure of roads both within cities and across the conterminous US. Despite differences in the evolution of these networks, there are commonalities: newer roads tend to become less grid-like. These results persist across the rural-urban continuum and are therefore not just a product of urban growth. These findings illuminate the need for policies for urban and rural planning including the critical assessment of new development trends.