Detection of warning surfaces in pedestrian environments: the importance for blind people of kerbs, depth, and structure of tactile surfaces.

Purpose: The overall purpose was to study whether and how persons with blindness detect warning surfaces with a long white cane in a real pedestrian environment after following a natural guidance surface to the warning surfaces. Of particular interest was the importance of kerb, depth, and structure of the warning surfaces.

Method: A concurrently mixed methods approach, with a combination of observation using a structured form together with 'think aloud' and a structured interview, was used.