Guidance TWSIs should consist of a pattern of parallel, flat-topped, elongated bars that extend in the direction of travel.
Guidance TWSIs are appropriate at the following locations:
- Transit stops
- Train stations
- Subway or light rail transit (LRT) platforms
- Sports arenas and stadiums
- Large open spaces (e.g., public squares)
- In the door areas of expansive open areas (e.g., shopping malls)
Follow these specifications for guidance TWSIs:
- Where installed to define a route, their width should be 250 – 300 mm.
- Where installed across a route as an indicator of an amenity or diverging route, their width should be 600 – 650 mm.
- They should have a minimum continuous clearance of 600 mm on both sides.
- The height of the bars should be four to five millimetres.
- The top of the flat-topped elongated bars should have a width between 17 and 30 mm.
- The bars should be colour contrasted to surrounding surfaces to make them easily identifiable by people with low vision.
- The width of the base of the bars should be 10 mm (+/- 1 mm) wider than the top.
- The top length of the bars should be at least 270 mm. If drainage is a concern, a space of 10 – 30 mm should be provided at the ends of the bars.
- The spacing between adjacent flat-topped bars should be adjusted depending on the size of the bars, as shown in the table below. The larger the individual bars, the more distant the space between them.
- Attention TWSIs should be used along tactile guidance paths to identify turns and other decision-making points. The attention TWSIs should be configured in a square pattern centred on the guidance TWSIs, with each side of the square being 600 mm - 650 mm.
|Top width of flat-topped bars (mm)||Spacing between the centre of adjacent bars (mm)|
|17||57 to 78|
|20||60 to 80|
|25||65 to 83|
|30||70 to 85|
An alternate type of guidance TWSI should be used on road surfaces to assist persons with vision loss to navigate complex road crossings including, but not limited to crossing at:
- Roundabouts, also known as traffic circles
- Mid-block crossings with four or more lanes
- Skewed intersections
- Offset crossings
It is important that the guidance TWSIs used on road surfaces are clearly different and distinguishable from the guidance surfaces used in pedestrian areas. Guidance TWSIs on road surfaces at pedestrian crossings should:
- Be configured as a straight path
- Be 250mm - 300mm wide
- Be detectable underfoot
- Be detectable with a long cane
- Be at least 50% colour/brightness contrasted with adjacent road surfaces
- Not present a tripping hazard
- Not present a barrier for persons who use wheelchairs or other types of mobility devices
- Be configured to mitigate damage from snow-plowing