The supply of residential mixed-use complex buildings began earnestly to address issues such as urban hollowing-out and increased traffic resulting from occupational separation in Seoul. Residential mixed-use buildings significantly met the demand for access to commercial facilities. The supply of residential mixed-use complexes has increased with the expansion of demand groups.

Although the size of individual housing units in residential mixed-use complexes decreases, the overall size of such complexes also increases. As a result, housing density is increased. This trend is accelerating with recent introduction of small flat-oriented residential mixed-use complexes, such as youth housing in station areas. However, the size of development, an indicator closely related to regional overcrowding, is currently managed solely through the floor area ratio, making it challenging to predict the number of households, population and resulting traffic congestion.

London introduced its design-driven approach guidance for the development of residential complexes with the release of the 2021 London Plan. Instead of merely focusing on housing density as a development project, this plan offers insight into how to manage population growth in the region and ensure the provision of essential urban services. In the case of Miami, a Form-Based Code (FBC) is implemented to address housing density through various concepts, including development density, housing density and job density. To make a vibrant urban core, standards that apply height and floor area ratios are designated and managed separately for areas requiring high-density residential development within the city.