linguistic:voice_change, structural:expansion
Types

Zoning codes have evolved over the years as urban planning theory has changed, legal constraints have fluctuated, and political priorities have shifted. The various approaches to zoning may be divided into four categories: Use-based (known as Euclidean in the US), performance, incentive, and form-based. Euclidean zoning codes with strict use separation are by far the most prevalent type in the United States.: 38 While the use of innovations such as form-based, performance, planned-unit development, and mixed-use zoning are common in the US, they tend to liberate relatively little land area from strict single-use zoning.: 85–92 Based on a survey of 25 cities, less than 5% of land allows mixed residential and commercial uses.: 90