Tactile Ground Surface Indicators (TGSI) Guide | Line Marking Australia Blog

Tactile Ground Surface Indicators (TGSI) Guide

A new shopping centre in Craigieburn installed tactile indicators throughout their carpark and entrances. Three months later, they received a complaint: the warning indicators at a hazard were installed as directional bars instead of dots. For someone using a white cane, bars mean 'follow this direction'—not 'danger ahead.'

Tactile Ground Surface Indicators (TGSIs) are textured ground surfaces that provide navigation information to people with vision impairment. Getting them wrong doesn't just breach the Disability Discrimination Act—it creates genuine danger for vulnerable users.

What Are TGSIs?

TGSIs are raised textured surfaces detectable underfoot and by long cane. They communicate two types of information: hazard warnings and directional guidance. People with vision impairment learn to interpret these textures through orientation and mobility training.

The Two Types:

Warning TGSIs (Dots):

Pattern of raised truncated domes (dots) arranged in a grid. These indicate hazards ahead—stop and assess before proceeding. Used at kerb ramps, stair landings, platform edges, and other hazard points.

Directional TGSIs (Bars):

Pattern of raised parallel bars oriented in the direction of travel. These guide users along a path—follow the bars to continue safely. Used to guide across open spaces or indicate the direction of an accessible route.

Applicable Standards

TGSI requirements are specified in AS/NZS 1428.4.1:2009 Design for access and mobility - Means to assist the orientation of people with vision impairment - Tactile ground surface indicators.

This standard is referenced by the National Construction Code and the Disability (Access to Premises - Buildings) Standards 2010, making compliance mandatory for new buildings and major renovations.

Where TGSIs Are Required

Warning TGSIs Required At:

• Pedestrian crossings and kerb ramps
• Top and bottom of stairs and ramps
• Escalator approaches
• Railway platform edges
• Overhead obstructions below 2000mm
• Vehicle crossings on pedestrian paths

Directional TGSIs Used For:

• Guiding across large open spaces (plazas, concourses)
• Indicating accessible path direction after warning TGSIs
• Connecting between building entrances and transport stops

Dimensional Requirements

AS/NZS 1428.4.1 specifies precise dimensions for TGSI elements.

Warning TGSI Dots:

• Base diameter: 25-35mm
• Top diameter: 15-25mm
• Height: 4-5mm
• Centre-to-centre spacing: 50-55mm

Directional TGSI Bars:

• Width at base: 17-30mm
• Width at top: 10-20mm
• Height: 4-5mm
• Centre-to-centre spacing: 45-55mm

Colour and Luminance Contrast

TGSIs must have adequate luminance contrast with the surrounding surface so people with low vision can detect them visually.

Requirements:

• Minimum 30% luminance contrast with surrounding surface
• Yellow and off-white are most common colours
• Black may be used on light-coloured surfaces
• Colour must be integrated, not surface-applied paint

Yellow is preferred in most situations as it provides good contrast against grey concrete and dark asphalt while being widely recognised.

Installation Methods

Discrete Units:

Individual tactile studs installed into drilled holes. Good for retrofitting existing surfaces. Requires precise drilling and adhesive application. Best for concrete and stone surfaces.

Integrated Tiles:

Pre-formed tiles with TGSI pattern incorporated. Easier installation, consistent spacing. Available in various materials including rubber, polyurethane, and ceramic.

Surface-Applied Systems:

Flexible polyurethane tiles adhered to existing surfaces. Quick installation, suitable for retrofits. May have shorter lifespan than embedded systems in high-traffic areas.

Common Installation Errors

We regularly see TGSI installations that fail compliance or create hazards.

• Wrong type used (bars where dots required, or vice versa)
• Incorrect orientation of directional bars
• Insufficient depth (300mm minimum for warning)
• Poor luminance contrast with surroundings
• Installed too far from hazard edge
• Missing TGSIs at required locations

Request a TGSI compliance assessment or installation quote

Frequently Asked Questions

Are TGSIs required in carparks?

Yes, at specific locations: pedestrian crossings, kerb ramps, stair approaches, and along accessible paths of travel. They're critical where vehicle and pedestrian traffic interact.

Can we paint TGSIs to refresh the colour?

No. Painting fills the gaps between elements and reduces tactile detectability. If TGSIs have faded, they should be replaced with new units that have integrated colour.

What's the difference between Australian and overseas TGSIs?

Different countries use different patterns and meanings. Products must comply with AS/NZS 1428.4.1 specifically. Japanese or US patterns are not compliant in Australia and may communicate incorrect information.