Which of the following was NOT a concept associated with planning urban environments?

Suburban sprawl is not considered a concept associated with planning urban environments in the same way that the other options are.

The term "suburban sprawl" describes a pattern of urban growth characterized by low-density, car-dependent development outside the city center. This phenomenon often results in the inefficient use of land and resources, as well as increased environmental impact and social fragmentation. It is generally viewed as a negative outcome of urban development rather than a planned concept or strategy.

In contrast, concepts like Marine City and Neighborhood Unit represent specific planning ideas aimed at structuring urban environments effectively. Marine City is often associated with innovative approaches to city planning that integrate water and marine environments, reflecting a progressive vision for urban living. The Neighborhood Unit concept emphasizes designing residential areas that foster community, encouraging social interaction and accessibility to services.

Motopia, although less known, refers to an idealized urban environment designed around the needs and experiences of motor vehicles, reflecting mid-20th-century planning principles.

Overall, while the other concepts aim to create structured, thoughtfully designed urban areas, suburban sprawl typically denotes a lack of planning and characterized by haphazard growth.