Tactile paving (also called truncated domes, detectable warnings, Tactile Ground Surface Indicators, detectable warning surfaces) is a system of textured ground surface indicators found on many footpaths, stairs and train station platforms to assist pedestrians who are blind or visually impaired.
Tactile warnings provide a distinctive surface pattern of "truncated domes" or cones (which are small domes or cones that have had their tops cut off, or truncated) or "truncated bars" detectable by long cane or underfoot which are used to alert people with visual impairments of their approach to streets and hazardous drop-offs. People who are blind or visually impaired are alerted of impending danger from vehicle impact or a grade change. There is a disagreement in the design community and the community of users if the interior use of these bars represents a tripping hazard.
Originally instituted at pedestrian crossings and other hazardous vehicular ways by countries like Japan, the United Kingdom and Australia, among others, the United States picked up the standard in the early 1990s, after passage of the Americans with Disabilities Act (ADA). Canada started incorporating the use in transportation first in the 1990s then added them to the built environment in early 2000s.
- 1 History
- 2 Tactile patterns
- 3 The role of color& contrast
- 4 Detectable Warning Surface Specifications
- 5 By country
- 6 Standards
- 7 References
- 8 External links
|This section requires expansion. (July 2010)|
The original tactile paving was developed by Seiichi Miyake in 1965. The paving was first introduced in a street in Okayama city, Japan, in 1967. Its use gradually spread in Japan and then around the world.
Today yellow tactile pavings are almost ubiquitous throughout Japan. For aesthetic reasons, for example in front of hotels, the colour of the paving can change to reflect the colour of the pavement or stone floor. Sometimes the paving contours are with steel stripes and dots.
The tactile tiles spread rapidly by having been adopted at Japan National Railways (later known as Japan Railway). It was established “The guideline for Tactile Tile installation for visually impaired person” in 1985. It can be classified into two types right now. Those types of tactile tiles with which function is different a tile to which cautions are urged. The round small bumps are arranged on the surface of the block, and attention is called through a sole. The second type of a block which shows a direction. Long and slender bumps are installed in the surface.
However, many types have been manufactured as an experiment and installed. This situation Produced not only a visually impaired person but the situation it was hard for elderly people to use. Furthermore, since the form with the various construction method appeared, a user's confusion was accelerated further. In the case of the person who has weak eyes walks, the color of a tile is using for check to the proper direction, and if the color is not clear, there is a problem that a tile is unclear. From such a problem having occurred mostly, the tendency anew improved about a Tactile Tile increases and examination of standardization in Japan is performed.
Now, these tiles are spreading in the world. There are many Tactile Tiles installed at subway stations and sidewalk in Seoul city. The installation situation in Seoul city has various problems more than Japan. Since the surface of a sidewalk is not flat, there are many places which do not have the meaning of a Tactile Tile. However, it can note that many such cares is carried out to a visually impaired person in Seoul.
The Tactile Tiles were adopted as each facility of the Sydney Olympic Games in Australia. And now, the tile installed to the public transportation facilities as ‘Tactile Surface Indicator’, and the design policy has also been considered by each local government. Such a trend has started also in UK and the US. Although the tile construction for visually impaired persons which started in Japan has many problems, it is spreading in the world. Japan should take the leadership in this field.
for Pedestrian Crossing Points, The purpose of the blister surface is to provide a warning to visually impaired people who would otherwise, in the absence of a kerb up stand > 25 mm, find it difficult differentiate between where the footway ends and the carriageway begins. The surface is therefore an essential safety feature for this group of road users at pedestrian crossing points where the footway is flush to the carriageway to enable wheelchair users to cross unimpeded.” The profile of the blister tactile surface consists of rows of flat topped blisters in a square pattern.
The blister tactile is intended for installation in the absence of an up stand at both controlled and uncontrolled crossings where:
- The footway has been dropped flush to the carriageway.
- The carriage way has been raised to the level of the footway.
Offset Blister Tactile
The offset blister tactile is also known as the “Platform Edge (Off-Street) Warning Surface”. “The purpose of this surface is to warn visually impaired people of the edge of all off-street railway platforms.” The off-set blister tactile surface consists of flat-topped domes(blisters), spaced 66.5mm apart from the center of one dome to the next.
The tactile paving units can be manufactured in any suitable paving material and may be any color that provides a good contrast with the surrounding area to assist partially sighted people. The current guidance recommends that the off-set blister tactile surface be used for all off-street rail platforms including:
- Heavy rail platforms
- Off-street light rapid transit (LRT) platforms
- Underground platforms
It should not be used for on street (LRT) platforms
The lozenge tactile is also known as the platform edge (on-street) warning surface. “The purpose of the platform edge (on-street) warning surface is to warn visually impaired people that they are approaching the edge of an on-street light rapid transit (LRT) platform.” The profile of the lozenge tactile warning surface comprises rows of 6mm (±0.5mm) high lozenge shapes, which have rounded edges so as not to cause a trip hazard. The tactile paving units can be manufactured in any suitable paving material. The surface is usually buff colored, but can be any color, other than red that provides a good contrast with the surrounding area to assist partially sighted people.
The lozenge tactile paving units should be installed to a depth of 400mm parallel to the platform edge and a minimum of 500mm back from the edge. It should never be installed closer to the edge than this because pedestrians may not have sufficient time to stop walking once they have detected the tactile warning surface.
Corduroy Hazard Warning Tactile
“The purpose of the corduroy surface is to warn visually impaired people of the presence of specific hazards: steps, level crossings or the approach to the on-street light rapid transit (LRT) platforms. It is also used where a footway joins a shared route. It conveys the message ‘hazard, proceed with caution.’”
The profile of the corduroy tactile surface comprises rounded bars running transversely across the direction of pedestrian travel. The bars are 6mm (±0.5) high, 20mm wide and spaced 50mm from the centre of one bar to the centre of the next. The tactile paving units can be manufactured in any suitable paving material. The surface is usually buff coloured, but can be any colour, other than red, that provides a good contrast with the surrounding area to assist partially sighted people.
The corduroy tactile can be used for any situation (other than pedestrian crossings) where visually impaired individuals need to warn of a hazard, such as:
- The top and bottom of stairs
- At the foot of a ramp
- At level crossing
- Where people may unintentionally walk directly on to the platform at a railway station
- Where a footway joins a shared route 
Cycle way Tactile
“The purpose of the tactile surface used in conjunction with a segregated shared cycle track/footway is to advise visually impaired people of the correct side to enter. The purpose of the central delineator strip is to help visually impaired pedestrians to keep to the pedestrian side.”
The cycle way tactile comprises a series of continuous raised, flat-topped bars, each 5mm (±0.5mm) high, 30mm wide and spaced 70mm apart. The central delineator strip should be 12 –20mm high, 150mm wide with sloping sides and a flat top of 50mm. The delineator strip should be made of a white material.
The tactile surface should be used on any segregated shared route where the pedestrian side is not physically separated from the cyclist side. The tactile surface should be laid at the beginning and end of the shared segregated route, at regular intervals along its length and at any junctions with other pedestrians or cyclist routes.
Directional or Guidance Tactile
“The purpose of the guidance path surface is to guide visually impaired people along a route when the traditional cues, such as a property line or kerb edge, are not available. It can also be used to guide people around obstacles, for example street furniture in a pedestrianized area. The surface has been designed so that people can be guided along the route either by walking on the tactile surface or by maintaining contact with a long cane.” The guidance tactile compromises a series of raised, flat-topped bars running in the direction of pedestrian travel. The bars are 5.5mm (±0.5) high, 35mm wide spaced 45mm apart, It is recommended that the guidance path tactile be in a contrasting color to the surrounding area so as to assist partially sighted people. The guidance surface is recommended for use in the following circumstances:
- Where the traditional guidance given by a standard footway between the property line and carriageway does not exist
- Where pedestrians need to be guided around obstacles
- Where a number of visually impaired people need to find a specific location and in transport terminals to guide people between facilities.
The role of color& contrast
The Department of Transport guidance on the installation and use of tactile paving places a heavy emphasis on the role of contrast. The guidance repeatedly states that tactile paving should be chosen to provide strong color contrast with the surrounding paving material as studies have shown that this aids partially sighted individuals. Most tactile paving is available in range of colors and materials making good color contrast easy to achieve with appropriate choice of tactile paving. There are only two cases where the color of a tactile has a specific meaning:
- Red is reserved for use with blister tactile to denote a controlled pedestrian crossing
- Buff blister tactile are reserved for use at uncontrolled pedestrian crossings
Where installation of tactile paving of a specified color e.g. red blister paving at a controlled crossing, would result in the tactile paving being of a similar color to the surrounding paving a contrast strip of at least 150mm should be installed to clearly demark the tactile area.
Detectable Warning Surface Specifications
Detectable warnings should be placed for a width of 24 inches in the direction of travel and extend the full width of the curb ramp or flush surface.
The detectable warning should be located so that the edge nearest the curb line or other potential hazard is 6 to 8 inches from the curb line or other potential hazard, such as a reflecting pool edge or the dynamic envelope of rail operations. Placement of the detectable warnings at a maximum of 6 to 8 inches back from the curb line gives some latitude in placement of the detectable warning. Where curbing is embedded at the sidewalk/street junction, this will not need to be replaced. In addition, allowing 6 to 8 inches of ramp (or curb) surface beyond the detectable warning will give pedestrians who are blind an additional stopping distance before they step into the street. It will also enable some persons having mobility impairments to make a smoother transition between the street and the curb ramp.
Dome Size and Spacing
Truncated domes should have a diameter of 0.9 inch at the bottom, a diameter of 0.4 inch at the top, a height of 0.2 inch and a center-to-center spacing of 2.0 inches to 2.35 inches measured along one side of a square arrangement. The size and spacing of the domes affect detectability by pedestrians who are blind. This specification is much more detailed than that in the current ADAAG, and offers much less latitude in dimensions and spacing. It ensures that the dome spacing is the maximum currently known to be consistent with high detectability. The diameter measurement in the present ADAAG is ambiguous if the user of these guidelines is not told whether the diameter is to be measured at the bottom or the top of the truncated domes. As currently implemented by most US manufacturers, it is the bottom diameter that measures 0.9 inch, and the top diameter varies widely. The diameter of the dome where it touches the sole of the shoe affects detectability, and the top diameter of 0.4 inch is based on current research.
Domes should be aligned on a square grid in the predominant direction of travel to permit wheels to roll between domes. This specification ensures the greatest degree of safety and negotiability for persons with mobility impairments. It requires square alignment, to give persons using wheeled mobility aids the greatest chance of being able to avoid the truncated domes. PROWAAC recommends 2.35-inch dome spacing but it may be difficult to acquire prefabricated elements or templates at greater than 2-inch spacing. Availability over time should improve and 2.35-inch spacing is strongly preferred. (E) Visual Contrast: There should be a minimum of 70 percent contrast in light reflectance between the detectable warning and an adjoining surface, or the detectable warning should be “safety yellow”. The material used to provide visual contrast should be an integral part of the detectable warning surface. Both domes and the underlying surface should meet the contrast recommendation. Visual contrast can be measured in accordance with existing ADAAG, A.2.9.2, appendix.
The Australian Human Rights and Equal Opportunity Commission (HREOC) released Guidelines on access to buildings and services in 2007, under the Disability Discrimination Act 1992. This recommends the use of Australian Standard AS/NZS 1428.4:2002 Design for access and mobility - Tactile indicators. The standard specifies the use of truncated cones, rather than domes (as used in the USA). HREOC describe the use of the standard.
In Canada detectable warning surfaces have in recent years started to be found in many provincial and municipal building standards (supplements to the building codes). These standards require detectable warning surfaces in prescribed locations, such as on the slopes of pedestrian curb cuts/curb ramps, exterior and interior ramps, at the top of stairs and on landings, and at the edge of rail platforms. Detectable warning surfaces include both truncated domes and tactile bars.
One of the first architectural standards for buildings requiring the use of detectable warning surfaces was the City of London Facility Accessibility Design Standards (FADS). The difference from the American ADA standards is the two different types of tactile surfaces required . At stairs, detectable warning surfaces are required (long bars that in USA are called "directional bars" but are placed at perpendicular to the main path of travel), whereas offset truncated dome detectable warning surfaces are used for ramps, elevated platforms (like those found at the edges of boarding platforms in transit facilities), and at other areas where pedestrian ways blend with vehicular ways.
In the U.S., tactile warnings systems are required by the ADA. The federal government, through studies and guidance provided by advocates and the Access Board, now mandates detectable warnings in prescribed locations, such as on the surface of pedestrian curb cuts and at the edges of rail platforms. Detectable warnings have been required for the edges of rail platforms in the United States since 1991. Detectable warnings for pedestrian curb cuts were suspended for study in 1994, and became officially required in 2001.
The ADA Accessibility Guidelines (ADAAG) require these warnings on the surface of curb ramps, which remove a tactile cue otherwise provided by curb faces, and at other areas where pedestrian ways blend with vehicular ways. They are also required along the edges of boarding platforms in transit facilities and the perimeter of reflecting pools. The raised pattern of domes also known as truncated domes are the preferred design for detectable warning tiles and pavers.
The usage of tactile paving in many circumstances will be required in the United States as part of the Americans with Disabilities Act. Adoption of truncated dome-mats has been controversial in some areas including Sacramento, CA.
Specifications for current enforceable ADA detectable warnings truncated domes regulation for the general public, is the United States Department of Justice 28 CFR part 36 Revised as of July 1, 1994.
Excerpt from ADA 4.3 Accessible Routes, 4.3.6 Surface Textures, 4.5 Ground Floor Surfaces, 4.5.3 - Carpet, 4.5.4 - Gratings - Textures. To date it appears none-of the detectable warnings manufactured, comply with 4.3.6 of the ADAAG. In addition, testing for being a non-hazardous surface placed in public walkways has not been conducted. In the appendix - some common sense reasons are illustrated about textures and their effects on the mobility impaired - A.4.5 Ground and Floor Surfaces. A4.5.1 General. People who have difficulty walking or maintaining balance or who use crutches, canes, or walkers, and those with restricted gaits are particularly sensitive to slipping and tripping hazards. For such people, a stable and regular surface is necessary for safe walking, particularly on stairs. Wheelchairs can be propelled most easily on surfaces that are hard, stable, and regular. Soft loose sand or gravel, wet clay, and irregular surfaces such as cobblestones can significantly impede wheelchair movement. 705 below has not been adopted by the DOJ for the general public and is therefore not enforced by the DOJ.
Specifications for ADA Detectable Warning Truncated Domes United States Access Board – ADAAG Specifies:
705 Detectable Warnings
705.1 General. Detectable Warnings shall consist of a surface of truncated domes and shall comply with 705.
705.1.1 Dome Size. Truncated domes in a detectable warning surface shall have a base diameter of 0.9 inch (23 mm) minimum and 1.4 inch (36 mm) maximum, a top diameter of 50 percent of the base diameter minimum to 65 percent of the base diameter maximum, and a height of 0.2 inch (5.1 mm).
705.1.2 Dome Spacing. Truncated domes in a detectable warning surface shall have a center-to-center spacing of 1.6 inches (41 mm) minimum and 2.4 inches (61 mm) maximum, and a base-to-base spacing of 0.65 inch (17mm) minimum, measured between the most adjacent domes on a square grid.
705.1.3 Contrast. Detectable Warning Surfaces shall contrast visually with adjacent walking surfaces either light-on-dark, or dark-on-light.
In London, tactile ground surface indicators are installed at many locations throughout the city, near historical buildings like Big Ben, Buckingham Palace and the British Museum as well as in downtown and residential areas. Tactile ground surface indicators are installed in accordance with unique standards established by the United Kingdom’s Department for Transport. Blocks with dots and blocks with bars are used, but both types are intended as warning blocks; neither serves a directional function. Blocks are mainly installed before crosswalks, at medians, at station platforms and at the top and bottom of stairways. Blocks with dots are for installations at crosswalks, medians and station platforms while blocks with bars are for installations at stairways. The color of blocks installed before crosswalks is also supposed to vary with crosswalk type: red blocks are to be used be- fore zebra crossings (where pedestrians always have the right of way), pelican crossings (equipped with push-button traffic lights) and puffin crossings (with sensor-equipped push button traffic lights) while other colors (yellow, grey, etc.) are to be used at other cross- walks where automobiles have the right of way. The difference in color is intended to assist people with low vision navigate the crosswalk safely, but many locations do not conform to the established colors. Different color blocks are also sometimes installed when repairs are made. Blocks are installed in an L-shaped configuration at crosswalks with push-button traffic signals, with the corner of the L marking the location of the push button. Blocks with bars are installed at the top and bottom of stairways such that the direction of the bars is parallel to the long dimension of the treads.
In Paris, warning blocks are installed before cross- walks, at the top and bottom of stairs leading in and out of subway stations and on subway and train platforms. In some areas, blocks serving a directional function are installed within crosswalks. Most blocks are white but black, grey and pale yellow are also used. To protect the scenery, subway station signs and other prominent manmade objects are not installed near historical sites such as the Arc de Triomphe, the Paris National Opera, the Louvre or the Place de la Concorde but Tactile ground surface indicators, in colors that stand out (white and yellow), are an exception Paris has recently been emphasizing barrier-free accessibility, including such experimental efforts as the uniquely configured blocks installed at the Montparnasse rail station .
In Frankfurt, blocks are installed inside rail and subway stations and on the platforms at rail, subway and tram stations. Many blocks are white, although some are grey. The warning blocks inside rail stations are of similar configuration to those used in Japan. The direction- al blocks used at train stations and the blocks used at subway and tram stations are uniquely German in con- figuration. Directional blocks at train stations are made up of thin linear protrusions. Directional blocks are installed at rail station platforms but no warning blocks—only non-slip strips with small dot-shaped protrusions located at the edge of the platform. Tram stations use the same directional blocks as at rail sta- tions but warning blocks are never used at platform edges or where blocks intersect.
In Brussels, blocks are installed before crosswalks, at bus stops and at subway and rail stations and platforms. Most blocks are grey, with yellow, silver and black blocks also used. Brussels has a mix of locations where the blocks (warning and directional) and installation methods are similar to those in Japan and locations where block configuration and installation methods are unique to Belgium. One of the Belgium-specific blocks uses metal disks of roughly 85mm in diameter and 8mm in height. In Japan, the prescribed size of warning block protrusions is 22mm in diameter (±1.5mm) and 5mm in height, a size designed to promote mobility by the visually impaired without impeding the movement of wheelchair users or elderly pedestrians. Given the large size, height and slipperiness of the metal disks used in the Belgian blocks, one suspects that they present a significant obstacle for wheelchair users, children and the elderly. In one part of the city, metal bars are embedded in the road surface where one would expect to find warning blocks (at the top of stairs and escalators, for example). Being only 3mm in height, these protrusions create no obstacle for wheelchair users or elderly pedestrians but also seem likely to go unnoticed by the visually impaired. In some places, similar metal bars are embedded in the road surface and serve a directional function. Rubber warning blocks are also sometimes installed at bus stops where directional blocks intersect. Brussels, therefore, presents a mix of block types and installation styles that may create confusion for people with impaired vision.
In Amsterdam, blocks are installed before crosswalks, at medians and on tram and subway platforms. Both warning blocks and directional blocks are installed ac- cording to the same rules as in Japan. Netherlands-specific blocks are used in addition to blocks configured like those in Japan. Most directional blocks are white or grey while warning blocks are yellow or grey. Where directional and warning blocks are used together the color of the blocks is often not uniform. Netherlands-specific blocks include some with thin recessed lines . With very little surface irregularity, such blocks are extremely difficult to detect with the feet or a white cane. Grooves carved into the pavement at subway station platforms are also difficult for people with impaired vision to recognize.
Tijuana uses landmark installations before crosswalks that are similar to those used in California. There are, however, no installations of Tactile ground surface indicators. -===Sydney=== Australia In Sydney, blocks are installed at rail, monorail and light rail station platforms, before exterior stairways, before exterior obstacles, at airports and at bus stops. Warning blocks and directional blocks are similar to those used in Japan, and installed in the same way, including at the Opera House and other well-known tourist spots. Unlike many other countries, however, blocks are not installed before crosswalks. As some rail, mono- rail and light rail stations, directional blocks lead from at or near the ticket gates to the platform. Blocks are yellow, silver, blue, green and grey. Blue blocks are frequently used at rail stations while yellow is often used at monorail and light rail stations.
In Auckland, warning blocks are installed before cross- walks in the city center, at rails stations and platforms and before interior stairways at shopping centers and other large-scale facilities. In suburban areas, directional blocks and warning blocks are installed before crosswalks to create a T-shaped configuration of about 1-1.5m. In addition, directional and warning blocks are also installed in areas with facilities for people with disabilities. Such blocks are installed in the same man- ner as in Japan. Blocks are most often yellow, with silver and white also used.
In Korea, warning blocks and directional blocks are in- stalled in accordance with Japanese rules in many locations including sidewalks, subway and rail stations and platforms, public facilities and large shopping centers. The configuration of the blocks, with the exception of some subway stations in Seoul, is the same. Blocks are yellow, silver, brown, white and grey. Because installation methods are adopted whole cloth from Japan, many of the same errors are found.
Tactile ground surface indicators are installed broadly in major cities such as Beijing, Shanghai, Dalian and Guangzhou. They can also be found winding through suburban areas surrounding major cities; the volume of blocks installed is second only to Japan. Both warning and directional blocks are used, and installed in a manner roughly the same as in Japan. Some areas have their own rules, however, such as in parts of Guangzhou where no blocks are installed where directional blocks intersect, a location where warning blocks would normally be installed. Block colors include yellow, grey, green, brown and beige. As in Korea, because installation methods are adopted whole cloth from Japan, many of the same errors are found. Maintenance is also inconsistent; here and there one sees broken blocks that have been left unrepaired.
Taiwan As in Korea and China, in Taiwan warning blocks and directional blocks are installed in accordance with rules nearly identical to those in Japan. Most blocks are yellow, with grey blocks also in use. Tactile ground surface indicators are frequently installed across the entire sloped area leading to a crosswalk, creating an obstacle for wheelchair users and others. In addition, although there are many stepped areas on sidewalks in the city center, very few are marked with warning blocks. This is dangerous for people with impaired vision and fails to accommodate their needs.
In Hong Kong, Warning and directional blocks are found at and around rail stations and warning blocks are installed before crosswalks and at medians in the city center. Blocks are yellow, silver, black, grey, green and brown. Installation methods are roughly the same as in Japan.
In Singapore, warning and directional blocks are installed primarily around subway stations. Installation rules are roughly the same as in Japan. Only a very few crosswalks in urban areas are equipped with warning blocks. Blocks are silver, yellow and grey.
In Kuala Lumpur, blocks are installed mainly at rail, subway, LRT and monorail stations and the surrounding sidewalks. In some locations warning and directional blocks are installed as in Japan while in other locations directional indicators are carved into the pavement and warning blocks are installed where direction- al markers intersect and where pedestrians are to stop. The latter practice is often followed at rail and LRT stations but the two types were found to coexist at one location. Blocks are yellow, silver and grey.
In Jakarta Warning blocks indicating the entrance to parking lots are installed on the sidewalks in Jakarta's Jalan Thamrin business area, an installation method unique to Indonesia. Blocks of this type are in- stalled at nearly every parking lot entrance, making for a great many installations. Warning blocks are also in- stalled before some crosswalks in the Jalan Thamrin area. No blocks are installed outside this area, however. Blocks are yellow in color.
In Bangkok, Warning and directional blocks are used on many side- walks in central Bangkok. Warning blocks are also in- stalled at the top and bottom of stairways at subway and monorail stations. Blocks are not, however, in- stalled at rail stations or rail platforms. Installation rules are roughly the same as in Japan. Blocks are yellow or grey. Many damaged blocks seem to be left unrepaired. Bangkok is a city with many vendors who set up shop on sidewalks; these frequently end up covering the blocks.
- Australia / New Zealand AS/NZS 1428.4:2002 Design for access and mobility - Tactile indicators
- United Kingdom BS 7997:2003 Products for tactile paving surface indicators. Specification
- Japan JIS T 9251:2001 Dimensions and patterns of raised of parts of tactile ground surface indicators for blind persons
- The good, the bad and the ugly – design and construction for access
- Access Board
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