The purpose of Tactile Ground Surface Indicators (TGSI) is to give pedestrians who are blind, or who have vision impairment warning of hazards and directional information to aid navigation of the urban environment. Tactile Indicators are products made from various materials installed into the ground consisting of a series of raised studs or bars. They are installed in the form of laid paving units, individual mushroom shaped studs drilled and fixed into the ground or mats glued to the ground surface.
This is achieved by aligning the raised stud or bar pattern of the Tactile Indicators on the ground surface, enabling blind pedestrians to feel the textural changes through their feet or with a cane. Pedestrians with limited vision use the color contrast between the Tactile Indicators and ground surface to detect the modules visually.