Visitability is the conecpt championed by Eleanor Smith and Concrete Change:
While the concept of Visitability is very simple, the definition has several interactive layers: spirit, features, scope, and moment in history.The spirit of Visitability is as important as the list of features.
That spirit says, it's not just unwise, but unacceptable that new homes continue to be built with basic barriers--- unacceptable, given how easy it is to build basic access in the great majority of new homes, coupled with the harshness lack of access inflicts on so many people's lives. . These barriers cause daily, draining drudgery; physically unsafe conditions; social isolation; and undesired institutionalization. The appropriate means of furthering basic access in virtually all new homes is, any means short of violence-- handing out information; legislation; incentives (so long as they are moderate and don’t undermine a tax base, impede general affordable housing, or damage other Visitability efforts); voluntary efforts (so long as they are not programs that produce few houses and exist mainly to forestall legislation); street theater; advertising campaigns; civil disobedience; …and others.
Second, the features list must be partly rigid and partly flexible. The inflexible Visitability features are:
Wide passage doors At least a half bath/powder room on the main floor At least one zero-step entrance
Source:
Visitability Defined 2003
http://www.concretechange.org/Definition_of_Visitability.htm