9.4 Modern-day Electronic Travel Aids

A second problem affecting validity also arose in the second project, which, in fact, must be borne in mind in all user-focused assessments of electronic travel aids. With e-mail interviews it is not obvious to the participants whether the actual researcher is disabled or what the nature of the researcher’s impairment is. In one case, a participant contacted the researcher to request that some of their responses be changed, after they realised that the researcher was blind. It is not clear why these changes were requested or how widespread this problem is. However, it does raise questions about validity of data. When involving blind or visually impaired people in research it must be borne in mind how the individual researcher may themselves inadvertently influence the responses of participants, even by something as unavoidable as their own impairments.

9.3.4.4 Other Methods for Assessments

Establishing a set of user requirements and using these as the basis for an expert evaluation of electronic travel aids is only the beginnings of a comprehensive user-focused assessment. More robust and comprehensive methods need to be employed if any assessment is to be thorough. Few blind or visually impaired people have direct experience of any kind of electronic travel aid and hands-on experience for users, during assessment, is an important element. User trials, such as those used in the first project described above, where users can test a device within a controlled setting, and field trials, where users can test a device within their everyday lives, are essential for a detailed user-focused assessment.

9.3.4.5 Flaws in the Assessments Presented Here

It should be borne in mind throughout this chapter that the assessments presented here are based on heuristic evaluations against a set of user requirements. These requirements were generated through consultation with blind and visually impaired people. However, this does not constitute a comprehensive user-focused assessment. Keep in mind that what is presented here is only a beginning and is intended to stimulate further user-focused research, where the needs of users, the tasks they need to perform and the context in which they operate are primary considerations to which technology should be adapted.

9.4 Modern-day Electronic Travel Aids

The electronic travel aids discussed in this chapter are a selection of those currently available. They cover both primary and secondary travel aids and both mobility and navigation aids. They utilise a range of technologies—pulse laser and sonar, sweeping sonar and optics. They also make use of a range of different outputs— vibratory and simple and complex auditory. The discussion considers only those electronic travel aids that are carried by the user and require no specific modifications to the environment, though both navigation devices discussed here do use satellite signals.

300 9 Electronic Travel Aids: An Assessment

9.4.1 The Distinction Between Mobility and Navigation Aids

Blind and visually impaired people face two types of challenges when on the move. One is to identify a safe path avoiding and negotiating obstacles and hazards. Such obstacles and hazards may include stationary objects such as posts, walls, signs, overhanging branches, stationary vehicles, moving objects such as pedestrians or moving vehicles, and other hazards such as steps, platform edges or icy patches. This is the challenge of mobility. Aids that assist with detecting, avoiding, negotiating and identifying obstacles and other hazards can be categorised as mobility aids. They assist people in moving safely.

The second challenge faced by blind or visually impaired travellers is that of knowing the current location and establishing how to get from the current location to a destination. This is the challenge of navigation or way-finding. Aids that assist with identifying the current location or a route from one location to another can be categorised as navigation aids—they assist people in finding their way.

9.4.2 The Distinction Between Primary and Secondary Aids

Travel aids can also be categorised as either primary or secondary aids. Primary aids are those which can safely be used alone; they provide sufficient information for the blind or visually impaired traveller to move around independently. The widely used long cane and guide dog are examples of primary aids. So, too, are the UltraCane, LaserCane, and the BAT “K” Sonar Cane, which are discussed later in this chapter.

Secondary aids are those that do not by themselves provide sufficient information for a blind or visually impaired person to safely and independently get around. They must be used in conjunction with a primary aid. They enhance rather than replace the information provided by a primary aid. Secondary aids include the Miniguide, the vOICe, the BrailleNote GPS and the Victor Trekker, which are discussed later in this chapter.

9.4.3 User Requirements: Mobility and Navigation Aids

Most blind travellers, just like most sighted travellers, want to be able to get from one place to another safely, easily, efficiently and with dignity. This wish for a convenient and bother-free journey underlies most of the requirements users have for mobility and navigation aids. It should influence all aspects of the design of mobility and navigation aids, including their appearance, how they output information, how they are operated, and the functions they provide.

In this section we will discuss some of the key user requirements for mobility and navigation aids. This is by no means a comprehensive examination of user requirements, as further research is needed and many requirements will be different for specific devices, tasks, environments and users. Rather, it is presented as a summary of core user requirements and to make explicit the key criteria against which the electronic travel aids discussed later in this chapter have been assessed.

Many requirements apply to all types of electronic travel aids—mobility or navigation, primary or secondary. Few users make a distinction between types of travel aids. For these reasons, this section also makes little distinction. Not surprisingly, requirements relating to appearance, output and operation, for the most part, apply to all types of travel aids and greater distinction between types of devices is seen in the functions that they serve.

Appearance and physical characteristics The prime issue for users relating to the physical characteristics and appearance of travel aids is that they should be unobtrusive, inconspicuous and easy to carry. They want devices that are discrete, do not draw attention from others, are not alienating and are not visibly expensive high tech. For convenience of carrying users want devices that are small and light weight and consisting of a single unit. Since travel aids will be used outdoors in all weathers and where accidents are relatively likely, users also feel that an essential criterion is that they must be extremely robust, able to withstand all weather conditions and able to withstand knocks and falls.

Operation Users need devices that are simple to operate. It must be quick and easy to change modes or issue commands. This is of particular importance for those with additional impairments. For example, those with limited dexterity require buttons that are easy to use and for those with cognitive impairments the operation must be easy to remember and, where appropriate, prompts must be provided. Accidental issuing of commands should be guarded against, for example by a key lock.

One aspect of operation that is of particular importance to many users is the ability to easily and instantly silence the travel aid. This is especially significant as it ensures that the user can speedily attend to other crucial sensory information, such as a public announcement or somebody speaking to them.

It is also important that users can operate the device in a real travel setting where they may have other things to carry or hands may be cold, limiting dexterity. Many users consider hands-free operation extremely useful.

One area of user requirements, relating to operation, which needs further research is that many users wish to be able to choose between different methods of operating a device. For example, a user may prefer the discrete and quiet option of pressing buttons whilst amongst other people but may prefer to use an automatic speech recognition system when away from others and perhaps in environments where their hands may be otherwise occupied or wearing gloves to protect them from cold.

Simplicity of operation applies not only to normal use but also to maintenance. The user must be able to change batteries easily, for example. Similarly, if the system relies on a database, such as is the case with navigation aids, it must be simple for the user to update that database.

Output How the device outputs information to the user is of great importance. The user must be able to make sense of the information provided by the travel aid. User control and choice over output is vital. This should be no surprise. Consider the many diverse situations in which a travel aid may be used—a quiet, obstruction-free country lane, a hushed, cluttered library, a crowded shopping

302 9 Electronic Travel Aids: An Assessment

street or alongside a busy road. Users need to be able to adjust the volume and intensity of output to suit the situation and their individual needs. Many users would also like to be able to choose between different modes of output. For example being able to select between auditory or tactile output.

Choice and control are also key in what information is output from the device. Users need to be able to select what information they are given. This is especially true for the more complex devices, navigation aids in particular, where the aid can provide huge amounts of information. Users want to be able to select to be given only certain information. For example if using a navigation aid on a familiar route they may wish to choose only to be told when they reach a point where they have to turn, whereas, on an unfamiliar route they may wish to be given much more information about where they are and what they are passing. Related to this is the need for information to be prioritised. Being warned of an impending collision may be of higher priority than being told what the object is. Being told to turn left at the next intersection may be of higher priority than being told that the user is passing a side street on the opposite side of the road. Similarly, for some users, being told the location of ramps, for example, is essential whereas other users will not require this information. Users want to be able to set their own priorities.

Function Most users consider reliability, accuracy and consistency of information vital. Many users, in fact, consider consistency to be more important than the specific information provided. If the device informs the user of the location of objects or landmarks, it must provide the equivalent information, at the equivalent time, for all objects and landmarks. If this cannot be achieved, some users would prefer to have no information about any objects or landmarks than to have information about some but not about others or to have information at inconsistent times. It is also vital to many users that weather conditions do not interfere with the functioning of the travel aid.

A distinction can be made between two groups of mobility aids. One group provides information only about the presence or absence of an object and its approximate distance (or time until impact). This group includes the Miniguide, Ultracane and Laser Cane. The second group provides richer spatial information, enabling users to perceive the form of objects and spatial relationships. This group includes the BAT “K” Sonar Cane and the vOICe software. Further research is needed to investigate the relative effectiveness of these two groups of devices in different settings and with different users. Dodds (1988) describes how the psychologist Alfred Leonard believed that users of the Sonar Torch (from which the BAT “K” Sonar Cane has developed) were filtering out much of the information it provided. Leonard believed that the complex spatial information was largely being ignored and that users were using it as a yes-no, safe-not safe device. This view is fiercely contested by its inventor, Leslie Kay, whose research shows the complex spatial information is understood and used by users (Kay 1980, 2000). Both these groups of mobility aids enable a user to make judgements about whether they are safe to continue on their planned path. Those providing richer spatial information assist the user in identifying objects. This means that users can better use objects as landmarks. Takamiya and Hamada (1998) emphasise the importance of landmarks

in enabling blind and visually impaired people to navigate on both familiar and unfamiliar routes. This suggests that object identification will assist blind and visually impaired travellers. Are all users able to process and act upon this rich source of spatial information? Is this information needed for independent travel, in all situations? Is it of greatest use in certain situations? These questions must yet be answered by objective research in real-world settings.

Navigation aids, combining geographic information systems and global positioning systems, to give blind and visually impaired people access to maps and to real-time positioning information, attempt to address the significant challenge blind and visually impaired people face in navigating. They provide blind and visually impaired people with access to map information that is equivalent to that available to sighted people. This is a very positive step. However, if we take a closer look at the needs of blind and visually impaired people we find that the navigation information they need or would like goes beyond that needed or wanted by sighted people.

The MoBIC project (Petrie and Johnson 1995; Petrie et al. 1995, 1996, 1997; Petrie 1996; Gill, 1997) used a combination of interviews, user trials and field trials to establish user requirements for a navigation system and to evaluate a navigation aid. The results of the MoBIC project (Strothotte et al. 1995, 1996) and the results of the first project describe in Section 9.3.4.1 show that blind and visually impaired travellers require navigation information specifically designed for their needs. Broadly speaking the additional information required by blind and visually impaired pedestrians falls into two overlapping categories—additional route information and landmarks.

First, blind and visually impaired travellers need extra information that assists them in identifying and following a safe route. This may, for example, include information such as the location of pedestrian crossings, whether there are shared pedestrian and cycle ways and whether or not there are pavements. For some users, it is essential that they are able to identify wheelchair accessible routes. It is of limited help if a navigation aid, for example, tells a blind or visually impaired traveller to turn down a road if in order to do so they must cross a road with railings in the middle of it to prevent people crossing. Although those with good mobility skills may be able to overcome such difficulties, those who are less able and less confident travellers may not and may be discouraged by them.

Second, there is information about landmarks. This may include information about direction and angle of gradients, floor surfacing or fixed obstacles such as telephone boxes. Note that this type of landmark is slightly different to those typically used by sighted people. Sighted people may use building such as pubs or petrol stations as landmarks. These are ineffective as landmarks for blind or visually impaired travellers as they may be unaware of them or have difficulty identifying them. Landmarks for blind or visually impaired travellers must be immediately identifiable and within their awareness. Landmark information serves a number of purposes including a means of validating positioning information, thereby giving the user greater confidence, and enabling a user to continue following a planned route even if satellite signals are unavailable, for example if they have been blocked by tall buildings. Without this additional information blind and visually impaired people may find themselves unable to follow a planned route,