The Galactic City Model, also called the Peripheral Model, describes a city where independent suburban areas and edge cities orbit a central urban core, similar to planets around a star. Developed by Chauncy Harris in 1997 based on cities like Detroit, the model shows how car-dependent development, interstate highways, and beltways push growth outward into self-sufficient suburban nodes with their own shopping centers, office parks, and entertainment. Unlike concentric zone or sector models that focus on a strong downtown, the Galactic City Model captures how many American metro areas function today, with multiple activity centers spread across a wide region connected by highways rather than public transit.
The Galactic City Model has influenced urban planning by emphasizing the importance of transportation networks in shaping metropolitan growth patterns. It reflects and affects trends in decentralization, affecting housing markets and job distribution within urban regions.