Tactile Paving Dot Pattern vs Bar Pattern: When to Use Each

The two most commonly confused elements of tactile paving specification are the dot (blister) pattern and the bar (corduroy) pattern. They look similar, they are often installed in the same project, and they are available in the same materials and colors. But they have completely different functions — and using the wrong pattern in the wrong location is a code violation that may mislead visually impaired pedestrians into danger.

This guide explains what each pattern means, where each is correctly installed, and how the two work together in a complete TGSI system.

The dot (blister) pattern: Warning

The dot pattern — technically described as “truncated domes” or “flat-topped blisters” in international standards — is a warning indicator. Its function is to alert a pedestrian with visual impairment that they are approaching a hazard.

When a person using a white cane or navigating by feel encounters dot pattern tactile paving, the correct interpretation is: STOP. There is a hazard ahead.

Dot pattern tactile paving is installed at: - The edge of a train or metro platform (warning that the platform edge — and a drop to the track — is ahead) - The top of a staircase (warning that steps are immediately ahead) - The bottom of a staircase (warning of the approach to the stair zone from the floor level) - At pedestrian crossings (warning that vehicles may cross the pedestrian path) - At the head of a ramp (warning of a change in level) - At any location where a pedestrian following a guidance path would encounter a hazard if they continued without stopping

The dot pattern always means: STOP AND ASSESS. It never means: CONTINUE IN THIS DIRECTION.

The bar (corduroy) pattern: Guidance

The bar pattern — technically described as “rounded bars” or “corduroy” pattern — is a directional guidance indicator. Its function is to guide a pedestrian along a designated safe route.

When a person using a white cane or navigating by feel encounters bar pattern tactile paving, the correct interpretation is: CONTINUE IN THE DIRECTION THE BARS ARE POINTING.

The bars are always oriented parallel to the intended direction of travel. A pedestrian following the bar pattern (bars running underfoot in the direction of movement) is being guided along the correct path.

Bar pattern tactile paving is installed: - Along concourse routes in transport terminals (from the entrance to the ticket gate, to the platform, to the exit) - Along hospital corridors to guide patients and visitors with visual impairment from the entrance to key destinations - Along street-level pedestrian routes - In any location where there is an established, designated safe path that a visually impaired pedestrian should follow

Why you need both

A common specification error is to install only dot pattern (warning) without bar pattern (guidance) — or worse, only bar pattern without dot pattern at the hazard points.

A correctly specified TGSI system always uses both: 

- The bar pattern creates a navigable path from a starting point to a destination 

- The dot pattern appears at every hazard point along and at the ends of the bar pattern route — warning the user that a hazard (crossing, platform edge, stair) is at the transition point

Think of it as a road system: the bar pattern is the road; the dot pattern is the stop sign at every intersection and hazard.

In a metro station, the correct installation sequence is: 

1. Bar pattern from the entrance — guiding the user along the concourse 

2. Dot pattern at every direction change and decision point — indicating “stop and re-orient” 

3. Bar pattern continuing along the new direction 

4. Dot pattern at the platform edge — indicating “hazard: platform drop ahead”

A system with only the platform edge dot pattern and no guidance bars leaves a visually impaired user stranded at the entrance with no navigable route to the platform. A system with guidance bars but no dot pattern at the platform edge guides a user directly to the edge without warning.

Layout rules

Dot pattern zone dimensions: 

- Minimum zone depth (measured in direction of travel): 600mm (ADA) / 600mm (ISO) 

- Width: full width of the path or crossing 

- At platform edges: installed at 480–530mm (ADA) or 750–760mm (Australia) from the platform edge

Bar pattern path width: 

- Minimum: 2 bar tiles wide (600mm for 300×300mm tiles) 

- Recommended: 3 tiles wide (900mm) for main guidance routes 

- Maximum useful width: 4 tiles (1200mm) — beyond this width, cane users may lose track of the bar direction

Transition between bar and dot: 

- At every transition from bar (guidance) to dot (warning), the junction should be clearly marked by placing the dot pattern perpendicular to the bar pattern direction — the contrast in texture is the tactile signal that the guidance path has led to a hazard

Common installation mistakes

Bars parallel to hazard (wrong): If bar pattern tiles are installed with bars running parallel to (rather than toward) a hazard, users following the bars will travel alongside the hazard rather than toward it with a warning. This is a dangerous error.

Dot pattern used as decoration: Dot pattern tiles placed randomly or as visual interest features without any navigational function confuse and mislead visually impaired users who are relying on them for navigation.

Gap between bar and dot at transition: Any gap in the tactile surface between the end of the bar guidance path and the beginning of the dot warning zone means a cane user can pass through the gap without detecting either — potentially reaching the hazard without warning.

Single tile at decision point: A single dot pattern tile at a direction change is insufficient. The dot zone must be large enough for a user to stop, orient, and assess — typically at least 600×600mm minimum.

Material selection for dot vs bar

Both pattern types are available in identical materials: - TPU (best durability for outdoor/high traffic) - PVC (cost-effective for indoor/light traffic) - Stainless steel tiles (permanent installation, premium environments) - Stainless steel studs (dot) and bars (bar) — for inset installation flush with existing floor

The material choice is the same for both pattern types within a project. The pattern type changes; the material remains consistent.