This International Standard provides product specifications for tactile walking surface indicators (TWSIs) and recommendations for their installation in order to assist in the safe and independent mobility of blind or vision-impaired persons. This International Standard specifies two types of TWSIs: attention patterns and guiding patterns. Both types can be used indoors and outdoors throughout the built environment where there are insufficient cues for wayfinding, or at specific hazards. Some countries have adopted other designs of TWSIs based on the consolidated findings of science, technology and experience, ensuring that they can be detected and distinguished by most users. National standards, regulations and guidelines governed by national legislation specify where TWSIs are to be used. This International Standard is not intended to replace requirements and recommendations contained in such national standards, regulations or guidelines.