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Developments in Transport Information Systems Which May Affect Visually Impaired Users

Dr. John Gill
June 2003

Over the next few years there are going to be significant changes in real-time passenger information systems, not all of which will be to the advantage of visually impaired travellers. At the same time new technological methods for accessing information could be implemented if the transport providers are convinced that there is sufficient demand for such facilities.

Advance Information

The user often has a choice of methods to reach a specific destination, but there is rarely a single source which can provide information of the times and costs of all the options. One type of system likely to become more common is the automated telephone-based information system which incorporates speech recognition. These systems can work well if the caller has a reasonably standard query; however for the uninitiated these systems can be very confusing.

There is likely to be an increasing amount of information on the web (internet) but it may not be in the most accessible or usable format. Timetables are often shown in a complex tabular presentation which is difficult to access with speech output. Another method of accessing such information may be interactive television; as yet, these systems are largely inaccessible to visually impaired people.

Using a Terminal
There are already unmanned railway stations, and the transport operators will want more customers to purchase tickets from machines. These machines can be difficult or impossible to use if you cannot read the screen. It is possible for a ticket machine to have large characters on the screen or speech output, but it adds to the cost of the terminal.

In places such as shopping centres, car parks, railway and bus stations, locating an information terminal or cash machine can be difficult - particularly for people who are blind or have low vision. For low vision users, signs showing where a terminal is could be large and high contrast (preferably white or yellow characters on a dark background) and illuminated (preferably internally illuminated). One possibility is to use a contactless smart card, carried by the blind person, to trigger an audible signal from the terminal at a distance of a few metres.
The introduction of smart cards provides the opportunity to make machines much more 'user friendly' than they have ever been before. For a smart card could carry information that tells a terminal to:

  • allow the user more time.
  • larger characters for people with low vision.
  • audio output of non-confidential information.

Digitally stored speech can give very good quality audio, but it is effectively limited to pre-stored messages. Full vocabulary synthetic speech is often difficult to understand for naïve users, particularly if they have a hearing impairment.

A standard layout for keypads is essential for blind people. There are currently two common layouts for numeric keys; the telephone layout and the calculator layout, and a raised dot on the number 5 does not help identify which layout has been used. It is recommended that the telephone layout be used exclusively on public access terminals.

Colour should not be the only distinguishing feature between keys, since red/green colour blindness is not uncommon; if possible, the keys should have different shapes and be marked with symbols. People with poor manual dexterity or a hand tremor benefit from key tops which are concave. Ideally keys should be internally illuminated when the terminal is waiting for input from that keypad. Sound feedback in the form of sounds such as a 'beep' or 'click' when a key is pressed is helpful to many people. Tactile indication can be provided by a gradual increase in the force, followed by a sharp decrease in the force required to actuate the key, and a subsequent increase in force beyond this point for cushioning.

With touchscreen systems, it could be arranged that holding one's finger in the bottom right corner for at least two seconds indicates that one would like larger characters on the screen. Large characters will be difficult to implement on small screens.

Touchscreens can either be triggered by insertion or withdrawal of the fingertip. With the latter system, it is technically possible for the user to pass their fingertip over the screen and get speech output describing the active area they are touching at the time. Then the system is only triggered by withdrawing the fingertip from over an active area.

In some towns, bus stops are fitted with a visual display giving the destination and expected arrival time of the next bus. It would be possible to have speech output from this display; this could be activated by a button or a contactless smart card.

Contactless smart cards are usually proximity cards with a range of up to 10 to 20 cm; these are in common use for public transport ticketing in many countries. A vicinity card has a range from 10 to 2 metres, and may be used in the foreseeable future for ticketing. The receiving aerial would be around the doorway of the bus, and the maximum fare for the route would be taken from the card on entering the bus and the unused part refunded on leaving the bus.

Infra-red systems have been developed which involve a transmitter mounted on the bus stop and the blind person carries a hand-held device which gives out the audible message; the disadvantage of such systems is that they are expensive to install and maintain.

Another method of obtaining speech output from a visual display would be by a short-range radio link, such as Bluetooth, to a mobile phone handset. An increasing number of new mobile phones are equipped with Bluetooth as standard. This use of the mobile phone handset could also apply to screens on platforms at railway stations, and transmitters could also be mounted on buses giving their route numbers and destination.

On Board
In the last few years improvements have been made to the position, shape and visual contrast of hand rails on buses and trains. However a problem still exists in the range of different layouts used in various trains and buses. It is not always obvious where is the best location for a guide dog so as not to be trampled by other passengers.

Some trains have a visual display of the name of the next stop, and a few have an audible announcement. This is less common in buses, even though the technology is available. In circumstances where public audible announcements may be unsuitable, wireless systems could be employed to make the announcements available to the passengers who want them.

However there are still aspects which are difficult to resolve technologically. For instance the bus driver may not be able to stop precisely at the bus stop. In addition if the bus stops away from the pavement, cyclists may pass between the bus and the kerb.

Service Disruptions
Visually impaired users are very dependent on the transport system running in a predictable manner according to the timetable. It is when the system is disrupted that the information systems are often inadequate, provide inaccurate or out-of-date information and rarely provide it in a non-visual form. Even then it may be difficult for a visually impaired person to act on this information. This is the area which probably deserves the highest priority since disruptions are unlikely to reduce in the foreseeable future without a concerted effort to improve them.

Further Information
Gill J M Access Prohibited? Information for Designers of Public Access Terminals. ISBN 1 86048 014 4, May 1997, revised March 1998.

Gill J M Which Button? Designing User Interfaces for People with Visual Impairments. ISBN 1 86048 023 3, September 2000, 28 pp.

Gill J M Bluetooth: Can It Help Disabled People? Incisor, October 2000.

Gill J M Requirements for the Interconnection of Assistive Technology Devices and Information and Communication Technology Systems. July 2001, 54 pp.

Gill J M Developments in Electronic Vision Systems. April 2002.

Gill J M Developments in Mobile Communications. April 2002.

Gill J M Developments in Wireless Systems. April 2002.


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