A small lot subdivision is a tool for building detached, single-family homes on urban infill lots.  For example, a small lot subdivision might permit the construction of three detached, single-family homes on a single zoning lot zoned for 2-4 family development.  A report prepared by the Los Angeles architectural firm Modative and available for free on their website gives examples and much useful information on using small lot subdivisions.   The key to such developments in Los Angeles has been that city’s adoption, in 2004, of a special small lot subdivision ordinance.  The ordinance waives certain setback, lot coverage and other requirements that would otherwise prevent development of detached homes on smaller lots.   Small lot subdivisions often include easements for utilities and pedestrian and vehicle access to each detached home.  Because the homes are detached, an owners’ association is usually not necessary and insurance rates may be lower.  Detached units also mitigate conflict over sound transmission through walls and ceilings that often plague attached condominium and townhome developments.