There is evidence that objects in and of the built environment function as barriers or facilitators to accessibility for people with disabilities. Although there are many existing sources of information about accessibility, they often lack clear criteria to describe accessibility, explanations of barriers and facilitators to mobility, and coverage of multiple physical environments. Researchers have argued that wayfinding services (e.g., Google Maps) can help people with disabilities prepare to travel through the built environment, yet current wayfinding services include little to no information about accessibility. This dissertation aims to study accessibility, in the context of wayfinding, in indoor, outdoor and transitional environments for people who travel in wheelchairs and people with low to no vision. To this end, a qualitative ontological analysis of multiple sources of information regarding accessibility was conducted including analyses of important categories associated with accessible wayfinding; different information providers’ views on accessibility; and specific barriers and facilitators to accessibility. The results indicate that (1) people with low to no vision and people who travel in wheelchairs have different core wayfinding information needs, (2) a gap exists between the information people with disabilities and researchers provide on accessibility and that provided by standard guidelines, and (3) conceptualizing accessibility requires capturing actions performed by people with disabilities during every day travel along with characteristics of environmental objects. The resulting ontology could be leveraged to generate new criteria describing accessibility, new routing algorithms, or to attach provenance to existing accessibility criteria. The findings have implications for people who design wayfinding services and collaborative maps and people collaboratively collecting data on the accessibility of specific places
