Suitability Evaluation of Visual Indicators on Glass Walls and Doors for Visually Impaired People

Abstract

This contribution focuses on the marking of glass with high contrasting indicators in view of the special requirements of people with visual impairment. Such people may have difficulties in identification of glass surfaces as obstacles. This can lead to accidents and injuries. This circumstance can be alleviated by applying appropriate visual indicators on glass surfaces that would be otherwise difficult to detect. Toward this end, guidelines and regulations exist in respective standards for barrier-free construction. However, designers appear to be reluctant in implementing such measures. Moreover, the range of preferences and options with regard to the design and positioning of such markers are not fully understood. This circumstance motivated the research presented in this paper. In an original experimental set-up, people with impaired vision evaluated various design solutions for such visual indicators, regarding their visibility and perceptibility. Thereby, the following aspects of the indicators were investigated: design of signs (uninterrupted versus interrupted, arrangement, color), vertical placement, and opening signage. The results (both objective measurements of visibility and subjective feedback from the participants) facilitate the identification of preferable design solutions for visual indicators. As such, they are not only valuable toward accommodation of the special requirements of sight impaired persons, but can also support fully sighted people in inauspicious situations (e.g. under sub-optimal lighting situations, stress or distraction).