Article 2 of the French law of 11 February 2005 specifies that disability may be caused by deterioration “of one or more physical, sensory, mental, cognitive or psychological functions”. Among the sensory impairments, hearing loss and the difficulties it causes are still poorly understood by decision-makers and designers, who therefore find it difficult to take them into account in designing the mobility chain. However, there are many such impairments and many ways to improve the accessibility of the living environment for all those who have difficulty hearing or cannot hear. The purpose of this factsheet is to present the essential aspects of what is known about this disability. It also addresses the technical or organisational recommendations to be implemented in the context of improving the travel chain, in order to eliminate or mitigate the difficulties encountered by the persons concerned.