Development Sets

"Development sets" is our term for a type of mixed use development that seeks to maximize the number of useful businesses within walking distance, and thus minimize the amount of motorized transportation (cars or mass transit) necessary. The concept is also known as the "15 minute city" and variations thereof.

We consider five types of neighborhoods.

Source: Congress for the New Urbanism ¹, with density of 4-5 story and highrise apartments given by JHP Architecture ². Calculations assume walking at 3 miles per hour or biking at 12 miles per hour is possible in a straight line from the center of the neighborhood to any point. A residential density of 12 units per acre is assumed for the rowhouse scenario. In each case, two-thirds of the neighborhood is assumed to be residential, with the rest commercial space, light industry, parks, roads, etc. For each housing unit, 2.6 people are assumed.

We estimate the following routine needs of the general population.

The number of businesses of a given type, per capita, is calculated by dividing the U.S. population ¹⁹ by the number of businesses. The number supported in a neighborhood is determined by dividing the neighborhood population, as reported above, by the number of people served by a business, rounding down.

Advantages

A 15 minute city design improves health ²⁰.

Limitations

Employment can be a challenge in a self-contained neighborhood. Alain Bertaud documents how, despite the intentions of planners, jobs and residents in the satellite cities of Seoul, South Korea were generally not matched to each other ²¹. If a city is divided into neighborhoods with little transportation between them, there is a risk of segregation and ghettoization ²². The technocratic nature of a 15 minute city can disempower residents from the planning process ²³.