Disabled Access Guidance
Streetscapes Accessible for All
It is essential that design for people with mobility impairments should be to the highest possible standards. This requires knowledge of the capabilities of different types of people. This section provides information on the basic human requirements for ease of movement, in order for you to design or modify your streetscape so that it is accessible to everyone. Being generous with the allocation of space should be the aim.
In addition, many of Furnitubes products can comply with DDA Guidelines. Look out for the blue DDA Symbol against products.
FENCES AND GUARDRAILS
In common with other street furniture on or close by footways, guardrails should be clearly colour contrasted from their surroundings: simple galvanized railings are not acceptable. If, for reasons of economy, this type of railing has to be used it should at least have colour contrasted markings on it. These requirements also apply to rails around street works.
Guardrails should also be designed to prevent guide dogs from walking under the rails, but there should be sufficient openings between vertical members to ensure that children and wheelchair users can see, and be seen, through the railings. The top rail should have a smooth profile and, if intended to provide support, should be circular with a diameter of between 40 and 50mm.
There should also be an upstand a minimum of 150mm in height at the rear of the paved area, which can then act as a tapping rail for long cane users as well as a safeguard for wheelchair users.
Street furniture can cause problems for both wheelchair users and for people who are visually impaired. It is essential, taking account of heritage issues, to consider both the position of any furniture and the means of making it apparent to people with reduced vision.
Bollards are recommended to be at least 1000mm in height. The same minimum height (1000mm) applies to other freestanding objects such as raised flowerbeds, which should also be designed with rounded edges. Under no circumstances should adjacent bollards be linked with chain or rope as this is a hazard for blind and partially sighted people. Low level signs supported on two vertical poles (eg city maps) should have a lower tapping rail or skirting between the posts to prevent blind pedestrians inadvertently walking between them and colliding with the sign. The rail or skirting should be 300-400mm above ground level. The sign should not extend more than 150mm beyond the supporting posts.
Colour contrasted bands (150mm deep) on poles and colour contrast on the tops of bollards will help partially sighted people, but the choice of colour for the overall post or bollard also affects visibility. Grey poles in particular are often problematic as they tend to blend into the general background.
Standing is difficult and painful for some disabled people, particularly those with arthritis, rheumatism and back problems. It is therefore important to provide plenty of appropriately placed and designed seating at places where people may have to wait and along pedestrian routes.
Mobility impaired people need seating at reasonably frequent intervals. In commonly used pedestrian areas, and transport interchanges and stations, seats should be provided at intervals of no more 50 metres. Wherever possible seats should also be provided at bus stops and shelters. Seating should be placed adjacent to, but not obstructing, the pedestrian route and should be picked out in contrasting colours to help people with visual impairment.
SEATING AND WAITING AREAS
Use of public transport usually involves waiting, so provision of seating is important. In general, a variety of seating in an area is acceptable, provided that some of the seating is suitable for the needs of the Disabled. Guidance on conventional seat heights varies over the range of 420 - 580mm, with a median height around 470 - 480mm. Armrests are helpful for some people and should be placed about 200mm above seat level. Ideally at least one armrest should not be at the extreme end of the seat but set in so as not to restrict the lateral transfer from a wheelchair to the seating. They should also not restrict front or oblique transfer. A supportive back‑rest should be incorporated for at least 50% of the length of the seat. Refer to "BS 8300:2009+A1:2010 Design of buildings and their approaches to meet the needs of disabled people – Code of practice" for further guidance (Note: this standard does not refer to the actual seat surface shape. Furnitubes seats are available with a selection of curved or flat surfaces, to suit a variety of applications. (ie: a slightly curved or sloped surface can add comfort and assists with water run-off so that slats are generally kept drier.))
Seats placed in a row either should all have armrests or no armrests; a mixture within a single row can cause difficulties for visually impaired people. Seat widths are recommended to be a minimum of 500mm. In designing the layout of the seats, space should be left for wheelchair users to sit with their companions. For outdoor seating it is vital that rain water is not allowed to collect on any part of the seat; wire top or wire-mesh seats are an obvious way of preventing this. Seats should be made of vandal resistant, easy clean material.
SIGNAGE AND INFORMATION
Signs and information must be in forms that can be used by disabled people. It is particularly important to take account of the needs of visually impaired and to make information as simple and easily understood as possible. Simplicity helps everyone but particularly people with learning disabilities. The placing of signs is also important: reasonably close to, but not impeding passenger circulation areas. Signage has a very important role to play. It should encompass all the facilities within the area, particularly any services or facilities for disabled people such as accessible toilets, accessible buses, services etc, and should also say how far it is to each facility mentioned.
Given the limited distances that some ambulant disabled people can manage, it is essential for them to know how far away the facility or service is located.
A considerable amount of research has been undertaken on the design of signage and printed material. The general principles are summarised in the following sub-sections:
SIZE OF LETTERS
Size of letters should be related to the distance from which the sign will usually be read. Various research studies have produced a range of preferred size of letters in relation to distance and degree of visual impairment. As a general rule it is suggested that the letter height should be at least 1% of the distance at which the message will usually be read, subject to a minimum height of 22mm. If space permits, letter height should be greater than the one per cent rule.
The Sign Design Guide (see Bibliography) recommends the following character sizes:
• Long distance reading, for example at building entrances, a minimum size of 150mm.
• Medium range reading, for example direction signs in corridors, a size of 50-100mm.
• Close up reading, for example wall mounted information signs, a size of 15-25mm.
SYMBOLS & TYPEFACES
Symbols can have the advantage of simplicity and greater clarity but should not be used unless it is known that they will be understood by passengers and staff. Considerable research has been carried out into legibility of different typefaces. The general recommendations are that letters and numbers should:
• be Sans Serif;
• use lower case lettering, which is more readily distinguishable than uppercase (capital) lettering;
• use Arabic numbers;
• have a width to height ratio of between 3:5 and 1:1;
• have a stroke width to height ratio between 1:5 and 1:10, preferably in the band 1:6 and 1:8;
• character spacing the horizontal spacing between characters should be 25 to 50% of characters width and 75 to 100% between words; and vertical spacing between lines should be at least 50% of character height.
Examples of appropriate typefaces for signs include New Johnston (used by London Underground) Rail Alphabet (designed for British Rail), Futura, Folio, Helvetica, Standard, Airport and DfT Transport Heavy and Medium (expressly designed for clarity for traffic signs).
It is essential that characters on signs should contrast with the background of the sign. Apart from signs that are internally lit, dark text on a light background is preferable: eg black or dark blue on a white background though there may be occasions when light lettering on a dark background is preferable. The sign board colour should contrast with its background as this will assist with visibility and readability.
POSITIONING OF SIGNS
The optimum viewing angles for signs mounted on walls or other vertical surfaces are ± 30° in the vertical plane (from eye level) and up to 20° either side of a 90° line to the sign in the horizontal plane. In practice, it may not be possible to achieve the height implied by the optimum viewing angle because of obstruction from other passers-by, where for example the content of the sign is directional information that needs to be seen from a distance. Wall-mounted signs that contain detailed information; timetables, maps or diagrams, should be
centered around 1400mm from the ground, with the bottom edge not less than 900mm above ground and the top edge up to 1800mm above ground.
Many guidelines advocate the use of colour/tonal contrasted marking to identify street furniture, railing or boarding around street works, scaffolding, tactile paving surfaces and so on (it may not be appropriate to use such treatments in historic areas).
The main purpose of using contrasted marking is to help partially sighted people avoid obstacles that they might walk into or trip over. The dimensions and placing of colour contrasted bands on poles and similar obstructions are a minimum depth of 150mm placed with the lower edge of the band between 1400mm and 1600mm above ground level. Some guidelines advocate deeper bands (300mm) or more than one band (three dark, two light bands each 100mm deep), but the single band, minimum 150mm, is considered satisfactory by the Royal National Institute for the Blind (RNIB ).
The principles underlying colour and contrast have been researched in detail but, in summary, it is essential to ensure that the colours used contrast with their surroundings. Colours which appear to be different from one another in colour (chroma) can be very similar tonally (eg green and brown) and therefore do not give sufficient contrast. Contrast is the difference in reflectivity between two surfaces.