Older drivers generally tend to avoid driving at night, in heavy traffic, in conditions of reduced visibility such as fog, and alone (Hennessy, 1995; Planek et al., 1968; Schlag, 1993). They can do this, in part, because they tend to have fewer constraints on when they must travel than younger adults (Ball et al., 1998; Noble, 2000). However, some studies have shown specific links with visual impairment. For example, as drivers’ contrast sensitivity and difficulty adjusting to glare increases, they reduce night driving (Planek et al., 1968; Schlag, 1993). Nevertheless, older drivers with visual and cognitive impairment can still have a higher accident risk, even though they report modifying their behaviour (Ball et al., 1993; Owsley et al., 1991). Thus, even if people believe they have problems, and try to adjust for them, they may not succeed in compensating.
Holland and Rabbitt (1992) asked older people about their pedestrian activity, and looked for relationships with self-assessed vision and hearing. People who felt that their hearing had deteriorated in the past 10 years were more likely to say that they avoided walking along roads without pavements than other groups. Older
pedestrians generally reported avoiding going out in the dark and in bad weather. Older people who felt their eyesight had deteriorated in the past 10 years reported
that they had made no changes to their pedestrian behaviour because of it. However, in separate questions they did say that they avoided crossing busy roads at night. Similarly, although people who said they had difficulties seeing in the dark or at dusk did not say they avoided crossing the road at night, they were more likely to say they avoided crossing the road without pedestrian crossings and walking along roads that had no pavements, than other groups. Thus, the pedestrians did not
consciously connect their behaviour to difficulties they might experience with vision or hearing. Bailey et al. (1992) reported survey results indicating that older
pedestrians, aged over 56, in Orlando, Florida, avoided crossing roads at peak traffic times, at dusk, or at night.
Spackman (1986) surveyed 100 older people. Seven reported that their eyesight, and four that their hearing, made crossing roads difficult. More than half had spectacles for seeing at a distance, and 89% said they always wore them when crossing roads. Holland and Rabbitt (1992) found that many older people with poor visual acuity had distance spectacles, but were not aware that they ought to wear them for crossing roads or driving. Spackman’s data were gathered in the context of a road safety survey rather than during vision testing, which may account for the different levels of appropriate behaviour reported.
Although Holland and Rabbitt (1992) found no age differences in self-reports of vision and hearing difficulties, and no significant correlation between self-reports and objective measures for vision, their research did contain some findings that suggest older people may have awareness of some perceptual problems. First, they found that there was a good correlation between self-reports of hearing problems and objectively measured difficulties. Second, the correlation for vision among pedestrians who did not drive (r¼ 0.34) was of a similar magnitude to the one for hearing. It may have not reached significance just because of the low sample size (n¼14). It is also possible that the method used for scoring problems with vision may have attenuated the correlation.
Kosnik et al. (1988) used a self-report questionnaire to ask older people questions about visual difficulties. A range of questions was asked to assess their experience of different kinds of problem with vision. For example, they asked people whether they had difficulty reading small print to assess their near vision. They used factor analysis to validate the questionnaire, and compared the scores derived from this for different age groups. Several aspects of visual function were associated with
increasing awareness of problems among older people, although the rate of increase was not the same for all types of problem. Kosnik et al. argued that these were aspects independently known to show objective decline in older populations. Older people were therefore shown to be aware of visual impairments they would be expected to have. A key aspect of this result is that participants were not asked directly about the aspects of vision. Rather, they were asked about everyday experience of difficulties. For example, they were not asked ‘‘are you getting more short-sighted’’, but ‘‘do you have problems reading small print’’. This is not,
therefore, evidence for transparent knowledge of their own visual capacity, but for a correspondence with their experience.
The participants in the study by Holland and Rabbitt (1992) received feedback from an expert on their peripheral vision and their visual acuity in various lighting
conditions, and two-thirds reported then making changes to their road-use
behaviour. For example, they reported reducing their driving at night, wearing their spectacles, and checking for road users in the periphery of their vision. Importantly, those who had made such adjustments to their driving on their own initiative were significantly less likely to have experienced an accident in the previous three years. Owsley et al. (1991) reported that older drivers in the Jefferson sample who had received an eye problem diagnosis were more likely to steer clear of difficult driving situations. Thus self-testing, or greater useful feedback in professional testing, could be helpful.
One possible explanation for a link between experience of visual difficulties and moderation of driving could lie in people’s knowledge of minimum vision requirements for driver licensing. Some states in the USA, such as Illinois, issue daytime-only driving licences according to the severity of visual impairment (Staplin et al., 2001), and it could be that such schemes highlight particular hazards even to those with unrestricted licences.
Kline et al. (1992) found that older drivers who rated their visual ability as poor were more likely to report that they were sometimes ‘‘surprised’’ by other vehicles when merging with traffic, and that other vehicles appeared unexpectedly in their peripheral vision. As noted already, a large proportion of pedestrian casualties of all ages report that they did not see the vehicle that hit them (Sheppard and Pattinson, 1986), and so poorer detection of vehicles in peripheral vision is relevant to safety. In summary, some evidence suggests that older people have reduced awareness of decreasing perceptual function. For example, Holland and Rabbitt (1992) found no difference in the level of self-report between older and younger participants, and Lutman (1989) reported paradoxically lower self-reports of deafness among older people. On the other hand, other studies have found close links between self- reported problems and problems older people would be expected to have (Kosnik et al., 1988), and several investigations have found that experience of difficulty with vision can contribute to people’s decisions to alter driving activity. Awareness of visual problems does not imply an understanding of the biological or psychological mechanisms that are affected. It appears that, when relevant environmental feedback is available, older people can recognise at some level that they have perceptual problems. Kosnik et al.’s demonstration of awareness relied on questions about everyday activities, but feedback from other people, as well as everyday experience, can be effective (e.g. Holland and Rabbitt, 1992). However, there is no clear