Accessory or secondary dwelling units are a way to increase the population density of suburban neighborhoods. With an increase in density public transit is more likely to be successful and businesses within walking distance have more potential customers. For these reasons and others advocates for sustainable development around the country are promoting government action to make small additional homes legal.
In Virginia a special type of secondary dwelling unit has been made legal. HB 1307, "Zoning Provisions for Temporary Family Healthcare Structures," over rides local ordinances to allow a secondary dwelling unit to be temporarily placed on a property to provide a dwelling for an ill family member.
The dwellings require a doctor's authorization and are to be removed when the medical need has passed.
MedCottages (288 sq feet) are specifically designed for the infirm elderly. With remote monitoring, an overhead rail to allow easier transfer from bed to bathroom, roll in showers and HVAC which will allow either positive pressure to keep pollutants from entering the home or negative pressure to keep infectious agents from leaving the dwelling.
The dwellings rent for upward of $2000 per month and are intended as an alternative to nursing home care.
The video below is a bit lengthy but explains some of the ideas behind the MedCottage law and the inspiring story of its passage.