The problems of being an older driver: comparing the perceptions of an expert group and older drivers

Applied Ergonomics 1994, 25 (1) 17-27

The problems of being an older driver: comparing the perceptions of an expert group anti older drivers C A Holland* and P M A Rabbitt*

*Department of Psychology, University of Leeds, Leeds LS2 9JT, UK *Age and Cognitive Performance Research Centre, University of Manchester, Manchester M13 9PL, UK Driving instructors' observations of older drivers were compared with the experiences of older drivers themselves using two questionnaires. Instructors were asked to compare the ease or difficulty of teaching different skills to old and young pupils, and were asked what skills they would expect to have deteriorated in an experienced driver aged 70. Instructors found teaching most skills to older pupils more difficult than to younger pupils, especially vehicle control and where more than one source of information demanded attention at once. Older pupils learned skills involving attitude and safety mindedness more readily than younger ones. Accident statistics suggest that junctions are dangerous places for older drivers and specific difficulties suggested by the instructors gave clues as to why junctions should be so problematic. Some skills seem to be intrinsically difficult for older people, in that instructors suggested them for both older pupils and experienced drivers: for example, vigilance, speed and distance judgements and coordination. There were also skills that instructors noted learners found difficult that experienced older drivers did not, namely vehicle control skills, and there were problems older drivers had that older learners did not, namely complacency and poor attitude towards safety. Older drivers were unaware of many of the problems suggested by driving instructors and by previous research. Comparison of these problems (eg failures of attention) with those that the drivers were aware o f (eg fatigue)suggested that part of the reason for this lack of insight may be poor feedback. This is discussed with reference to directions for remediation. Finally, the effect of greater experience on older people's insight and willingness to make sensible adjustments to their driving was examined.

Keywords: Driving, elderly, self-monitoring, safety, feedback Introduction Older drivers, especially those over 70, are more at risk of having road accidents than middle-aged people (eg Broughton, 1988). They are also physically very much more vulnerable to the effects of these accidents, in terms of length of stay in hospital, the long-term adverse effects of injury, and even in death resulting from these injuries (OECD and WHO, 1986). Previous work has shown that older drivers' road accidents occur particularly at road junctions, especially where right turns (UK figures) are concerned (Moore et al, 1982). A common cause of accidents at junctions amongst older people is failure to yield right of way (OECD and WHO, 1985), perhaps because they fail to see oncoming vehicles. Rural junctions figure particularly in the Applied Ergonomics 1994 Volume 25 Number 1

accident statistics for older people, perhaps because they often tend to be poorly signed and have poor visibility. Frequency of accidents involving reversing also increases with age. Malfetti and Winter (1987) noted several other unsafe driving behaviours commonly observed in older drivers. These were: driving too slowly, failing to position the car correctly for turning, turning from an improper position or at an improper time or pace at intersections, especially when turning left (or right in the UK). Failure to signal before changing lanes and lack of knowledge of rules of the road were also mentioned. Inattention to driving also seemed a pervasive problem. Harteman (1981) calculated the median age of drivers deemed to be responsible for a fatal accident.

0003-6870/94101 0017-11 (~ 1994 Butterworth-Heinemann Ltd

17

The problems of being an older driver: C A Holland and P M A Rabbitt

This was 29 years for accidents involving two vehicles outside intersections, 24 for accidents where only a single vehicle was involved without striking an obstacle, 25 where an obstacle was struck, and 52 for accidents involving two vehicles at an intersection. Intersections at which a stop is necessary seem to pose particular problems in view of the added task of restarting the vehicle quickly at the same time as making decisions about the prevailing traffic situation. For example, Schmidt et al (1989) gave drivers of different ages a standardized driving performance test, using only drivers with normal or corrected vision. They found that the over-55s observed priority regulations 13.6% less frequently than younger drivers, and that this led to almost double the amount of traffic conflicts necessitating driving instructor intervention. Generally, older drivers seem to have greater difficulty interpreting and judging the movements and intentions of other drivers. A study by Hakamies-Blomqvist (1988) found that accidents of the elderly at junctions had fewer contributing causes than those of younger drivers. HakamiesBlomqvist concluded that junctions are dangerous for everybody, when several risk factors coincide, but that for the elderly, they are dangerous without any contributing risk factors. Hauer (1988) calculated that, in the USA, 40% of traffic fatalities and 60% of injuries to drivers in the 64plus age group occur at intersections. Most of these occur during daylight, whereas for the 24--64 age group most occur during darkness. More than a third of all fatalities and injuries occur at junctions where traffic is not controlled at all. Thus we know some of the situations in which older people tend to have accidents, and also some of the behaviours, common among older drivers, that are judged to be dangerous. However, we do not know whether these problems result from the physical and cognitive limitations of being elderly, from bad habits that have developed over a lifetime of driving, from over-confidence, or from a falling-behind in knowledge of the modem highway code. Further, we do not know the extent to which older drivers themselves are aware of factors that increase their vulnerability. Data collected by Holland and Rabbitt (1992) suggested that older people were certainly unaware of the extent of their declining eyesight and reaction times, and also that they did not perceive complex junctions as posing any particular problem to them. The British A A Foundation study (1988) noted that older drivers did not regard junctions as a problem; they considered their reaction times as good as when aged 50; and they also felt that their ability to cope with junctions and roundabouts was much the same as it had been at that age. However, previous work has noted that older drivers partly compensate for their growing limitations in their sensory and cognitive abilities (eg eyesight and reaction times) by increased caution, driving more slowly and reducing the amount of driving that they do (Rumar, 1986), and also by avoiding situations that they perceive 18

to be problematic for them, or that they find stressful (Holland and Rabbitt, 1992). The adaptations that older drivers make to their driving behaviour seem to be particularly important, since it has been noted (eg Rumar, 1986) that the number of accidents in which they are involved is not as great as one would expect, given our knowledge of slower reaction times, decreased processing capacity and poor eyesight. A common perception is that greater driving experience also compensates for the degenerative effects of ageing, but it seems that greater experience may have costs as well as benefits for driving safety. For example, Duncan et al (unpublished) noted that motorists with normal experience were actually worse than experts (advanced motorist test observers) and novice drivers in some important aspects of driving, such as scanning patterns (eg mirror checking), safety margins (eg headway on the motorway) and anticipation (eg braking into an intersection). It thus seems that the adaptations that older people make may be more important than previously thought. However, in the light of data outlined above, older groups of people are particularly unaware that they need to make these adaptations, in that they are not aware of much of the deterioration in, for example, eyesight and reaction times, nor are they aware that complex traffic situations may pose a particular problem for them. Duncan et ars examination of the skills found to be poor in normal experienced drivers suggested that these are skills in which feedback is rare and relatively poor unless an accident actually occurs, and that this lack of feedback may be the reason why ability may fail to improve, or even deteriorate, with experience. Naatamen and Summala (1976) noted that feedback is an 'efficient driving teacher' and that tasks that do not give sufficient feedback would be expected to improve little with experience. For this reason, the study described below examines the effect of years of experience on awareness of the different problems that occur with increasing age. The study was designed to try and identify the source(s) of older drivers' problems: whether old age per se is important or whether the problems are due to driving for many years with little feedback. To do this we designed a questionnaire for experts (driving instructors), probing their perceptions of whether older drivers have any specific, identifiable problems. They were asked which skills their older pupils found most difficult to learn and which skills (if any) they thought would have declined in a 70-year-old who had been driving for many years. This approached the question of whether older people, whatever their experience, find some skills intrinsically difficult. Further aims were to examine whether older drivers themselves are aware of the particular difficulties that are perceived by the driving instructors, and which have been identified by previous research. This was done by comparing the self-reports of older drivers (aged 50-90) on a second questionnaire with the driving instructors' responses on the first. Finally, the contribution of years of driving experience to the self-reports of the older drivers were also examined. Applied Ergonomics 1994 Volume 25 Number 1

The problems of being an older driver: C A Holland and P M A Rabbitt

Method The questionnaires Two questionnaires probed the experiences and opinions of driving instructors and older drivers. Driving instructors. The questionnaire for the instructors was printed in the Driving Instructors' Association bimonthly magazine Drive, asking readers to fill in and return. The magazine has a wide circulation among driving instructors in the UK. The first section of this questionnaire listed skills involved in driving and asked respondents to rate the ease/difficulty of teaching each skill to young (17-21) and old (50+) pupils. Respondents were asked to rate each skill on a scale of 1 (meaning very easy to teach) through to 5 (meaning very difficult to teach). Other questions asked what difficulties the instructors thought even very experienced older drivers might encounter, whether they thought drivers should be retested, what experience they had had of older pupils being involved in accidents, and what measures they felt might add to older drivers' safety. Older drivers. The second questionnaire was sent out to older people (those over 50 years old) who were members of the University of the Third Age (a British cultural/educational society for retired people), and to members of the University of Manchester Age and Cognitive Performance Research Centre's volunteer panels. This questionnaire included separate sections for drivers and for pedestrians, and a substantial section on general health, eyesight and hearing. This questionnaire is part of a larger project on road use and primary and secondary effects of sensory deficits in the elderly, and for present purposes we shall discuss only that subset of questions that were directly comparable with those included in the questionnaire completed by driving instructors. Subjects

Driving instructors. A total of 164 people responded. Six of these were not used, as they had not answered enough questions, or they had very little experience teaching older learners. All respondents included had substantial experience teaching older learner drivers, although a few of these had specified that they had little experience teaching older men. The analysis thus included 158 respondents who had completed most of the questions. They were aged between 26 and 61, the mean age being 43.17 (SD = 8.7). The mean number of years of experience of teaching was 8.23 years (SD = 6.3). As in any study where participation is voluntary and requires some effort, there may be some personality differences between responders and non-responders, but the large range of ages and amount of experience in the responding group suggests that the sample was representative of driving instructors, at least in these respects. Only three of the respondents were women, there being very few women driving instructors in the UK. Older drivers. The questionnaires were sent out to 1300 people on the panel, and 910 people (70%) replied. Of Applied Ergonomics 1994 Volume 25 Number 1

these, 39 did not complete all relevant questions on the questionnaire and were excluded from further analysis. The questionnaire was completed by 641 drivers and 230 non-drivers. The drivers were divided into four age groups: 110 people in their 50s, 340 people in their 60s, 172 people in their 70s and 19 people in their 80s. The mean number of years of driving experience of these respondents was 35.4 years (SD -- 12.70). The Manchester volunteer panel consists of people aged 50 upwards from most sectors of society, with some ethnic groupings being under-represented. The proportions of the sexes are 70% women and 30% men. Results Driving instructors' questionnaire Question 1. The results of one-way within-subjects analyses of variance on each of the presented skills are presented in Table 1. Instructors said that they found younger people easier than old people to teach most skills involved in control of the vehicle, particularly gear changing, clutch control (hill starts) and coordination of more than one control skill at once. The only skill of this type on which there was no significant difference between the age groups was speed control. Instructors reported that they found it easier to teach younger pupils most basic perceptual-motor skills involved in driving, eg judgement of a safe gap in the traffic when entering a road and, especially, coping in complex situations (a lot happening at once). However, the differences between the age groups were greater for vehicle control skills, such as clutch control and reversing. We may infer from this that driving instructors perceive more difference between old and young in learning to control the vehicle, than in general driving skills, or 'road sense', as some respondents put it. There were no significant differences between young and old for learning 'maintaining a safe distance from the car ahead' and 'awareness of dangerous situations'. Instructors felt that it was harder to teach younger than older people skills like 'safety mindedness' and'driving courtesy'. Factor analyses were computed on the first question. This was done separately for old and young in order to determine if components of skill correlated together into different factors for the different age groups. The analysis was computed using maximum likelihood extraction and varimax rotation. Only those factors with eigenvalues greater than 1 were considered. The results of the factor analysis on the instructors' opinions of teaching older people to drive are shown in Table 2. Three factors emerged: • Factor 1: Skills that could be described as 'vehicle control skills' correlated well with this factor, especially where the skill involved manipulation of more than one control, or one control plus some concurrent decision making. • Factor 2: Skills that could be summed up as 'carefulness' correlated well with this factor. • Factor 3: Skills that could b e summed up as 'perception and vigilance correlated well with this factor. 19

The problems of being an older driver: C A Holland and P M A Rabbitt

Table 1 Difficulty of teaching driving skills to old and young pupils Means Skills

Young

Old

Difference

F ratio

Vehicle control skills 1. Coordination of more than one control skill together 2. Clutch control (hill starts) 3. Gear changes 4. Reversing 6. Appropriate gear 9. Braking smoothly 13. Appropriate use of mirrors

2.8 2.3 2.2 2.7 2.7 2.6 2.7

4.3 3.6 3.7 4.2 3.9 3.3 3.1

1.5 1.3 1.5 1.5 1.2 0.7 0.4

445.26* 349.95* 326.51" 308.25* 255.80* 84.40* 18.95"

Perceptuo-motor skills 5. Coping in complex situations (at lot happening at once) 7. Steering and road position 8. Judgement of safe gap in traffic when entering a road 10. Judgement of when it is safe to overtake 11. Maintenance of vigilance 12. General awareness of traffic and pedestrians 14. Judgement of potential hazards 15. Noticing potential hazards 16. Maintaining a safe distance from the car ahead 17. Awareness of dangerous situations

3.1 2.4 3.0 3.4 3.2 3.0 3.2 3.1 2.9 3.5

4.4 3.6 3.8 4.1 3.7 3.4 3.6 3.4 2.8 3.4

1.3 1.3 0.8 0.6 0.5 0.4 0.3 0.3 -0.1 -0.1

276.56* 237.48* 103.86" 61.98" 31.18" 21.05" 16.67" 11.97" 1.76" 1.20"

Behavioural/attitudinal factors 18. Speed control 19. Driving courtesy 20. Safety-mindedness

3.0 3.2 3.4

3.1 2.5 2.6

-0.1 --0.7 -0.8

1.03 43.54* 60.13"

Note: High score means greater difficulty in teaching *p < 0.01

The same factor analytic technique was then applied to the data for the instructors' opinions of teaching young people to drive. Four factors emerged. The results are shown in Table 3. • Factor 1: Skills that could be summed up as 'carefulness' correlated well with this factor. • Factor 2: Items that could be described as 'vehicle control skills' correlated well with this factor. • Factor 3: Items that could be summed up as 'awareness of self in relation to traffic' correlated well with this factor. • Factor 4: Skills that could be summed up as 'awareness of danger' correlated well with this factor.

Tables 2 and 3 show that different variables cluster into different factors for the two age groups. A factor that could be summed up as 'vehicle control' accounted for the largest percentage of the variance in the equation for the older pupils, but a very different factor, which may be summed up as 'carefulness', accounted for the largest percentage of the variance in the analysis of instructors' opinions of younger pupils. The remaining items on the questionnaire consisted of requests for opinions on various aspects of old and young people's performance as drivers. The responses 20

were even more varied than the questions and so were analysed in terms of the percentage of respondents expressing each opinion. • Are there any other skills that old people found difficult to learn which have not been included in Question 1? Many responses included rephrasing or repetition of those already included. However, there were some important additions. These additions, and the percentage of respondents that gave them, are set out in Table 4. The most common responses were that older pupils found learning to park and turn around in the road difficult, and that they found it difficult to learn to keep up with other traffic. • What type o f accidents can occur when teaching older pupils? 46.8% of respondents said that a rear-end collision was the most common, or even the sole type of accident that they had experienced as instructors with an older pupil. This was slightly more than the percentage of instructors giving this answer for the same question about teaching younger pupils (44.9%). Few instructors said that accidents with older pupils occurred while emerging at junctions (3.8%), while 12.7% of instructors said that such accidents had occurred with young pupils. Failing to brake and poor steering were also noted as causing older pupils' accidents.

Applied Ergonomics 1994 Volume 25 Number 1

The problems of being an older driver: C A Holland and P M A Rabbitt Table 2 Factor analysis on instructors' opinions of older pupils Factor 1: Eigenvalue = 6.9209, percentage of variance

= 34.6% Variable

Clutch control (hill starts) Gear changes Appropriate gear Steering and road position Coordination of more than one control skill Braking smoothly Coping in complex situations (at lot happening at once) Speed control Appropriate use of mirrors

Correlation

0.77 0.73 0.66 0.64 0.64 0.60 0.51 0.46 0.40

Factor 2: Eigenvalne = 2.2367, percentage of variance = 11.2% Variable

Safety-mindedness Driving courtesy Maintaining a safe distance from the car ahead Judgement of potential hazards Awareness of dangerous situations Noticing potential hazards Appropriate use of mirrors Speed control

Correlation

0.81 0.80 0.69 0.62 0.52 0.51 0.45 0.35

Factor 3: Eigenvalue = 1.2887, percentage of variance

--- 6.4% Variable Correlation Judgement of when it's safe to overtake 0.78 Judgement of safe gap in traffic when 0.77 entering a road Awareness of dangerous situations 0.56 General awareness of traffic and 0.51 pedestrians Maintenance of vigilance 0.45 Note: Only correlations of more than 0.35 (df = 51, p = 0.01) are shown

• Do you think licensed drivers should be retested? 95%

said 'yes' and only 5% said 'no'. Those who had responded 'yes' were asked to state at what age(s) they thought this should be done. Responses were, again, very varied, but the most common ones are set out in Table 5. The most popular preferences were for regular tests for drivers of all ages. • What skills are likely to have deteriorated in a 70-yearold who has driven for many years? A variety of

changes were mentioned, but the most common were slowing of reaction times and decline in awareness and observation. Responses are set out in Table 6. • Other comments about teaching older people to drive.

Responses in this section included suggestions as to how driving instructors may best overcome the learning difficulties of older pupils, some further Applied Ergonomics 1994 Volume 25 Number I

comments on the positive and negative characteristics of older people, and a suggestion as to the possible benefits of automatic cars for all older drivers, but particularly for older learners. These comments are presented in Table 7. Older drivers" questionnaire Coping in complex traffic situations. The older drivers

were asked whether they avoided complex junctions in Table 3 Factor analysis on instructors' opinions of younger pupils Factor 1: Eigenvalue = 7.148, percentage of variance

= 35.7% Variable

Correlation

Safety-mindedness Driving courtesy Maintaining a safe distance from the car ahead Speed control Braking smoothly Appropriate use of mirrors Awareness of dangerous situations General awareness of traffic and pedestrians

0.73 0.72 0.72 0.70 0.56 0.50 0.48 0.48

Factor 2: Eigenvalue = 1.8926, percentage of variance = 9.5% Variable

Correlation

Reversing Clutch control Coordination of more than one control skill together Gear changes Appropriate gear Coping in complex situations (a lot happening at once)

0.74 0.74 0.65 0.62 0.54 0.51

Factor 3: Eigenvalue = 1.2410, percentage of variance = 6.2% Variable Correlation

General awareness of traffic and pedestrians Steering and road position Judgement of when it's safe to overtake Maintenance of vigilance Appropriate use of mirrors Judgement of safe gap when entering a road Appropriate gear Coping in complex situations (a lot happening at once) Awareness of dangerous situations

0.71 0.60 0.59 0.52 0.50 0.47 0.47 0.42 0.35

Factor 4: Eigenvalue = 1.1340, percentage of variance

= 5.7% Variable

Correlation

Judgement of potential hazards Noticing potential hazards Awareness of dangerous situations Coping in complex situations (a lot happening at once)

0.82 0.68 0.47 0.41

Note: Only correlations of more than 0.35 are shown 21

The problems of being an older driver: C A Holland and P M A Rabbitt

Table 4 Other skills that older people find difficult to learn

Skill Parking, turn in road Keeping up with other traffic/driving fast enough Retention of information/skills learned Roundabouts Busy traffic

Percentage of respondents 11.39 10.12 5.70 5.70 4.43

Table 5 At what age(s) should licensed drivers be retested?

Response Every 10 years Every 4-5 years At all ages following a traffic offence At 60--65 1-5 years after 'L-test' At all ages following a serious accident At 50 At 70 Every 3-5 years after age 60

Percentage of respondents 24.05 24.68 13.92 10.13 8.86 6.33 6.33 4.43 3.16

Table 6 Skills expected to have deteriorated in an experienced 70-year-old driver

Response Reaction times Reaction times but compensated for by driving slower/better anticipation General awareness of hazards/ anticipation Observation/mirror use/shoulder check Perception/eyesight Speed and distance judgement Coping with today's traffic Concentration/observation/vigilance Hesitancy/keeping up Coordination Complacency/attitudes Ability to plan ahead Appropriate gear for speed Steering Reversing

Percentage of respondents 30.48 4.43 28.45 27.85 24.05 18.99 12.03 12.66 11.39 8.86 6.96 6.33 5.70 5.70 3.80

their everyday driving. Overall, 155 out of the 641 drivers who answered this question said that they did (that is, just 24%). Fewer people in their 50s responded positively to this question than any other age group (just 12.7%). The overall age difference between the four groups was significant (F(3,640) = 3.295, p < 0.05). Years of driving experience correlated negatively 22

Table 7 Comments on teaching old learner drivers Percentage of respondents

Comment Need a lot of patience and encouragement Take much longer than young Old men and women equally difficult to teach Old women very timid Very rare indeed to teach old men Old men easier to teach All need repetitive lessons/close together Old women easier to teach/ideal pupil Usually very determined More sensible and aware of hazards Would benefit from an automatic car Old men are obstinate Frightened of modem traffic Almost impossible to teach/don't do it!

29.74 29.11 27.85 7.59 6.96 6.96 6.33 5.70 3.80 3.16 3.16 3.16 3.16 3.16

(r(634) = -0.17, p < 0.001) with avoiding complex junctions: that is, the more experience subjects had, the less likely they were to say that they avoided complex junctions. In order to determine how much the vast experience of these older drivers was confounding results, years of driving experience was entered as a covariate in the analysis of variance. The effect of the covariate was significant (F(1,629) --18,25, p < 0.001) and the effect of age group now increased to F(1,629) -----6.836, p < 0.001, demonstrating that age and experience have opposing elects on whether a person will consciously avoid complex junctions (or admit to doing so). When asked to rank in order ten different situations for how 'at risk' or anxious they would feel in each, turning right at a complex junction was judged to be one of the medium taxing situations, with mean rank = 6.06; this compared with items such as driving on a motorway in fog (mean rank = 8.8), a child running into the road (mean rank = 7.48), and attempting to overtake in the face of oncoming traffic (mean rank = 6.72)). There was no significant effect of age group. Reaction times, emergency stops. When subjects were

asked whether they felt that they still reacted as quickly in an emergency as they had when they were younger, only 24.6% said that they did not, and the rest felt that they reacted just as quickly as ever. There',was no significant effect of age group. Admission o f errors. Subjects were asked how often

they made certain types of errors, and to respond on a scale of 1 to 5, where 1 meant that they never made the error and 5 that they made it nearly all the time. The responses to this question are set out in Table 8. Some of these errors involved failures of awareness of other traffic, pedestrians or hazards. In response to the items Applied Ergonomics 1994 Volume 25 Number I

The problems of being an older driver: C A Holland and P M A Rabbitt 'Attempt to overtake someone you had not noticed to be signalling a right turn', 'Fail to notice that pedestrians are crossing when turning into a side street from a main road' and 'On turning left, nearly hit a cyclist who has come up on your inside', the majority of subjects said that they never, or very rarely made this error. There were no age effects. The same was true for responses to items querying the driving instructors' assertions that older drivers do not always use mirrors or gears appropriately ('Fail to check your rear view mirror before pulling out, changing lanes etc' and 'Attempt to drive away from traffic lights in third or fourth gear'), and that they have difficulties with the judgement of when it is safe to overtake ('Underestimated the speed of an oncoming vehicle when overtaking'). In response to the item 'Disregard speed limits', subjects said that they rarely, occasionally or often made this infringement, admitting to this more often than they admitted to any other error. The overall mean score was 2.08, but here there was an age difference; people in their 70s admitted to this less often than those in other age groups: F(3,627) = 2.585, p = 0.052.

Judgement of potential hazards. There were significant differences between the rankings of ten different situations in terms of how much they provoked feelings of being 'at risk' and of anxiety; (F(9,5562) -- 125.88, p < 0.081). People judged that 'Driving on a busy motorway in dense fog' was the most risky situation, followed by 'Having to stop suddenly because a child has run out in front' and 'Attempting to overtake in the face of oncoming traffic'. The situations judged to be least risky overall were 'Stalling at the traffic lights', 'Parking in a busy high street' and 'Trying to follow directions from a passenger in busy traffic'. There were no significant differences between the age groups in the order of ranks given (ie no age × rank interaction).

Table 8 Self-rated frequency of committing errors

Error Attempt to overtake someone you had not noticed to be signalling a right turn Fail to notice that pedestrians are crossing when turning into a side street from a main road On turning left, nearly hit a cyclist who has come up on your inside Fail to check your rear view mirror before pulling out, changing lanes etc Attempt to drive away from traffic lights in third or fourth gear Disregard speed limits Underestimate speed of an oncoming vehicle when overtaking

Applied Ergonomics 1994 Volume 25 Number 1

Mean (scale (of 1 to 5) 1.25 1.35 1.37 1.41 1.22 2.08 1.61

Night-time driving. Subjects were asked whether they found it particularly difficult to see in the dark or at dusk. The majority (78.2%) of respondents said that they did not. There was a significant difference between the age groups (F(3,632) = 3.967, p < 0.01), such that people in their 60s and 70s tended to say that they did not feel they had difficulty seeing in the dark and people in their 50s and 80s tended to say that they did. Subjects were also asked whether they avoided driving in the dark. Overall, few subjects said that they did (29.8%). However, there was a significant agegroup effect, such that people in their 80s were more likely to say that they avoided driving in the dark than any other age group: F(3,637) = 6.289, p < 0.001.

Busy traffic. Subjects were asked whether they avoided driving at rush hour. Overall, 42.9% said that they did. There was no difference between the age groups. Coping with emergencies (cf Driving instructors: 'The old panic'. Subject were asked whether they felt that they coped with emergencies as well as they used to. Very few people said that they thought they did not (19.6%), and there was no age difference. Subjects were also asked whether they were as confident on the roads as they were when they were younger. Overall, 30% said that they were less confident now, and there was no age group difference. Coping with modern traffic. Subjects were asked whether they thought that modern road conditions or failing faculties (such as eyesight and slower reactions) contributed most to the increase in road accident rates amongst the elderly. The majority of subjects said that they thought the answer was a combination of the two factors (76.7%). There was no age group difference. Fatigue. Subjects were asked" whether they avoided driving long distances. 42.1% said that they did. There was a significant effect of age group such that older groups (70s and 80s) more often said that they avoided driving long distances than did people in their 50s and 60s: F(3,637) = 8.99, p < 0.001. Again, years of experience correlated negatively with avoiding driving long distances (r(634) = --0.14, p < 0.001), whereas age correlated positively (r(642) = 0.19, p < 0.001), Years of experience was entered in the analysis of variance as a covariate. The effect of the covariate was significant (/7(1,629) = 12.47, p < 0.001) and the effect of age group increased to F(1,629) -- 16.53, p < 0.001, thus demonstrating that age and experience have contrary effects on whether someone will avoid driving long distances. Retesting. Respondents were asked whether or not they thought drivers should be retested at age 70. They were also asked whether or not they thought drivers should be retested every 10 years. The majority of subjects thought that retesting at age 70 was a good idea (69.7%). Fewer subjects (53.4%) thought that having a driving test every 10 years would be a good idea. 23

The problems of being an older driver: C A Holland and P M A Rabbitt

Discussion Situations in which instructors thought that older drivers had difficulty, were at risk or showed dangerous driving As noted in the introduction, it has been previously observed that junctions are particularly dangerous places for older people (Moore et al, 1982), because a high proportion of their accidents occur there. Speed and distance judgements were commonly specified by the instructors as skills particularly likely to have declined in older drivers who had been driving for many years. These components of coping with junctions may well be the basis of the accident figures. In answer to the question about accidents exprienced while teaching older pupils, many instructors responded that the most common type of accidents was rear-end collisions, mainly at junctions. It may be that a certain proportion of accidents at junctions are, in fact, rear-end collisions and that these are caused by undue hesitancy on the part of the older driver. Instructors did note that undue hesitancy was a particular problem even in older experienced drivers.

General observation, mirror use and shoulder checking were items not noted by previous studies as particular problems of older drivers, with the possible exception of shoulder checking, which has been noted as a difficult task for older people due to difficulty turning the head (AA Foundation, 1988), but not as a consequence of lack of care (which might be an imputation for failure to regularly check the rear-view mirror). These essential activities may be expected to decline with increasing experience, since failing to check is only rarely met with negative feedback. That is, in reality, failing to check in the mirror or over the shoulder is rarely brought to the attention of the driver because there is often nobody there anyway. Slowed reaction times and unduly slowed driving speed were very commonly suggested as important problems for elderly drivers by the driving instructors. It is now very widely recognized that reaction times decline with age, and the importance of this for driving cannot be overestimated. For example, Summala and Koivisto (1989) examined braking times in older drivers, and Staplin et al (1990) calculated projected brake reaction times as a function of age. In the present study, driving instructors frequently said that they would expect reaction times to have slowed in older drivers. Staplin et al remarked on the overwhelming agreement in the literature concerning the modest slowing in the simple motor response latency of older persons. They note that in driving tasks where the response alternatives are well learned (such as brake, accelerator and steering wheel control), it seems that only a small proportion of the variance in speed of response to situations is due to the slowing in the simple reaction time. However, the larger decline in choice reaction times with increasing age (eg Cerella, 1985), suggests that slowing in decision-making and response are perhaps more important factors than simply how quickly a person can put their foot on the brake. Although a few instructors felt that older people showed better anticipation than younger drivers, many more felt that general awareness of hazards and 24

anticipation declined with age. It may be that although awareness of what constitutes a hazard may improve with age and experience, concentration and vigilance may decline, as the driving instructors suggest. Some evidence for declines in concentration and vigilance have been found in experimental studies; for example, Stollery et al (1990) noted that older subjects show relatively more skewing of decision-time distributions with increased task duration than do the young, suggesting increased difficulties in maintaining attention during a continuous task. Driving instructors suggested that declines in perception and eyesight were particular problems for older drivers. While eyesight measures have been infrequently reliably related to accident rates and driving ability, the relationship does tend to be more reliable for older people (Hills and Burg, 1977). It is interesting to note that instructors generally observe that perception and eyesight, rather than eyesight alone, is the problem. Ball etal (1988) suggested that the diversity of findings of studies that attempt to relate eyesight to accident rates is due to an overemphasis on sensory testing. They suggested that perceptual/cognitive testing of eyesight that takes into account the visual complexity of the driving task (such as their 'useful field of view' measure) would be a more efficient predictor of driving ability and accident rates. Motor coordination was another problem suggested by driving instructors. We know that motor programming of movement is adversely affected by old age (eg Critchley, 1956), and we also know that even socalled 'automatic' tasks such as walking are affected by the presence of a secondary task (ConnoUy and Holland, unpublished). It is suggested that this problem of motor coordination in driving is one that requires urgent investigation. Some driving instructors did suggest that the use of automatic gear control may be useful for older drivers, and it is suggested that the reduction in number of motor tasks required in driving would be beneficial to the older driver, both in terms of the reduced demand on general cognitive resources and also the reduced demand on precision of motor control. Research needs to be done to determine how much the reduction in demand on resources brought about by using automatic gears is affected by the small amount of new learning involved in the change. Differences and similarities in the skills that instructors thought would have declined in older experienced drivers and the skills that instructors found difficult to teach to older pupils There are some skills that seem to be intrinsically difficult for older people, in that driving instructors noted that older learners found them particularly hard to learn, and also that these are skills that they would expect to have declined even in very experienced older drivers. Instructors said that they found it more difficult to teach older than younger pupils to be aware of potential hazards, to be aware of other traffic and pedestrians, and to judge potential hazards, and they said that they would expect general awareness and Applied Ergonomics 1994 Volume 25 Number 1

The problems of being an older driver: C A Holland and P M A Rabbitt

hazard anticipation to have deteriorated in older experienced drivers. However, the instructors did not feel that it was any more difficult to teach older learners to be aware of dangerous situations. It thus seems that being aware of what constitutes a hazard is no more difficult for older than for younger pupils to learn, and does not seem to decline with age. In contrast, general awareness and anticipation and the ability to notice relevant cues and to react appropriately to them does seem to be a general problem for older people. Other difficulties that appeared in response to both questions were: maintenance of vigilance and concentration, speed and distance judgements, judgement of a safe gap when entering a road, judgement of when it is safe to overtake, hesitancy and keeping up, busy traffic - dealing with a lot happening at once - and coordination. From experimental work on the cognitive abilities of older people, we know that older people's concentration and vigilance is generally poor; that they take in and process information more slowly than the young; that they are particularly compromised in situations involving complex decision-making (eg Salthouse, 1985) and also that their capacity to integrate information from different sources declines (eg Holland and Rabbitt, 1990). While older learner drivers would be expected to have extreme difficulty, since they find even tasks that later become moderately automatic to be cognitively taxing, experienced older drivers would also be expected to have increasing difficulties in maintaining the level of their skill. From the driving instructors' responses, it seems that there are few skills that are difficult for older experienced drivers that are not also difficult for older learners. Thus these are skills that may be intrinsically difficult for older drivers, regardless of experience. However, unlike elderly learners, older experienced drivers do not appear to have difficulty with vehicle control skills, for example clutch control (hill starts), gear changes and smooth braking. Factor analysis found that this particular group of skills correlated well with the factor that picked up most of the variance in all the driving instructors' ratings of the ease or difficulty of teaching older pupils to drive. However, in the factor analysis of instructors' ratings of teaching young people to drive, the single factor that accounted for most variance incorporated component skills that could be summed up as 'carefulness'. Complacency and attitude problems were noted by driving instructors as features of older experienced drivers, but the very opposite was noted as a feature of older learners, in that safety-mindedness and driving courtesy were felt to he something that older pupils very readily acquired. Finally, although instructors noted that appropriate use of mirrors was more difficult to teach to older learners than to younger, the rating of difficulty of teaching was one of the lowest, although it was one of the most common problems that the instructors associated with older experienced drivers. Thus it seems that there are some important driving factors that are declining with increased experience, rather than with age per se. Applied Ergonomics 1994 Volume 25 Number 1

On instructing older pupils The results of this study suggest that teaching older people to drive is quite a different task from teaching younger pupils. With younger pupils, greater emphasis is needed on the attitudinal components of driving behaviour, and on training to be aware of what constitutes a hazard. In contrast, it seems that training on perceptual skills may be a specific need of older learners. For example, Ball et al (1988) found that the useful field of view, a perceptual/cognitive measure of visual attention, does actually improve with specific practice, and it seems probable that a feedbackoriented skill such as speed and distance calibration would also benefit from training. Given that so many accidents involving older drivers occur at junctions, appropriate advice to older drivers may be to plan routes avoiding certain types of junction, such as unprotected right turns and crossroads on 'fast' urban roads. For example, it has been demonstrated that older drivers have fewer accidents on roundabouts, and this should be made known to older learners. Are older drivers aware of the problems specified by the driving instructors? Previous work has noted that older people often seem unaware of declines in abilities such as eyesight, hearing and reaction times (Holland and Rabbitt, 1992) and cognitive abilities (Rabbitt and Abson, (1990). The suggestion of this previous work was that middle-aged people (in their 50s) overestimate their decline, whereas older people (in their 70s) underestimate their decline.

Driving instructors suggested that complex junctions, roundabouts and complex situations presented a problem for older drivers, and we know that, in fact, a disproportionate number of older drivers' accidents do occur at junctions. Very few people overall said that they avoided, or felt at risk at, complex junctions. More of those who did say they avoided complex junctions were older, rather than younger drivers. Although driving instructors commonly suggested that reaction times would have slowed in older experienced drivers, and despite our knowledge that this is indeed the case, very few of the older drivers themselves felt that they reacted any more slowly than when they were younger. In general, subjects admitted to few errors. It may of course be the case that in answering this type of question, subjects were concerned to present themselves as being still 'fit to drive'. Specifically, subjects did not feel that they made many errors involving awareness of traffic and pedestrians or hazards, and there was no age effect in this. It may be that, by their very nature, such failures of awareness go unnoticed. The same may be true of people's admissions to failing to check their rear-view mirrors before pulling out from the kerb, or changing lanes. In an experimental study, Rabbitt (1990) suggested that the reduced informationprocessing capacity of the elderly makes them increasingly inefficient at monitoring their own performance, less aware of their errors and also less able to remember their occurrence. 25

The problems of being an older driver: C A Holland and P M A Rabbitt

Attempting to drive away from traffic lights in third or fourth gear is an error that gives greater feedback than perhaps forgetting to check the mirror before pulling out. Thus if the former error is a common mistake of older drivers, we might expect that they would admit to making it more often. However, again, very few people admitted to making this error. This is only one aspect of what instructors may have meant by suggesting that older drivers often fail to use the appropriate gear; it may be that what they have in mind is that older drivers forget to change up or down while their vehicles are in motion and their attention is distracted by other demands. Several driving instructors said that speed control was a problem for older experienced drivers. Indeed, older drivers themselves did admit to breaking the speed limits more often than they admitted to any other error. This may be because such a violation is not seen as a failing of ability, but rather of attitude, and so is a more acceptable admission for the old. In the rank ordering of the ten risky situations, older people (70s and 80s) seemed as aware as younger people (50s) of what generally constitutes a risky situation, but they did not seem to be aware that some driving scenarios, such as complex junctions, that are not generally viewed as dangerous, have in fact become specifically dangerous for them as older people. The results on night-time driving are interesting in that previous work showed that the oldest group (the 'over 70s') did not particularly avoid driving in the dark or at dusk and that they-did not particularly feel that their eyesight in such conditions had deteriorated, despite the fact that objective tests carded out on them showed that their vision had deteriorated in poor lighting conditions (Holland and Rabbitt op cit), and despite our knowledge that, in the population at large, dark-adapted threshold sharply increases (sensitivity decreases) with age (McFarland and Fisher, 1955). The present questionnaire study showed that although the people in their 60s and 70s did not feel that their vision in poor light had declined, and people in their 50s more often did, the extra age group in this study, the drivers in their 80s, did feel that their eyesight in poor light had declined. It appears that while older people are generally unaware of their limitations, when these limitations become markedly severe, as we would expect them tO do for people in their 80s, people are forced to recognize them, even if their onset has been slow and insidious. The fact that people act sensibly to mitigate their limitations once they recognize them is borne out in the finding that people in their 80s also said that they avoided driving in the dark or at dusk more often than any other age group. Driving instructors said that they would expect older experienced drivers to have problems coping with today's traffic. Older drivers themselves agreed with this, almost half of them saying that they now avoided driving in the rush hour. The majority of older drivers felt that older people's accidents were caused by a combination of modem road conditions and failing faculties (eyesight, reaction times etc). Almost a third 26

of the older drivers said that they now felt less confident on the road than they used to. Finally, older people did seem to be aware that they became fatigued more easily, in that almost half said that they avoided driving long distances. Older people (70s and 80s) particularly avoided driving long distances. Many documents giving advice to older drivers exist (for example, the A A produces one) but the need for self-monitoring and feedback seeking cannot be overemphasized.

Conclusions Thus older drivers are aware of many changes in their driving ability, but not necessarily all those that driving instructors and laboratory studies identify as important and likelyto reduce driving efficiency. It is important to note that they are not oblivious of all of these potential problems. It seems that those factors that older people fail to recognize are just those that provide either no, or only 'terminal' feedback: that is, become evident only when they result in an accident. The responses to questionnaires strongly suggest that amount of driving experience tends to have the opposite effect to advancing age in terms of promoting cautious behaviour. That is, it seems that while increasing duration of experience makes it increasingly unlikely that a person will avoid a situation known to be dangerous for older people, when the effects of experience are partialled out, increased age makes it more likely that age-associated hazards will be recognized and that caution will be increased. The important question now is the extent to which increased experience actually can and does compensate for the effects of increased age and, further, what effect increased years of experience have on older people's attitudes towards making sensible changes when they are given information about the adaptations that they may need to make. Bearing all this in mind, the results suggest that older people are aware that they are generally at risk and that there may be problems for many in their age group, despite the lack of awareness of specific problems. This is shown by the finding that most older drivers endorsed the idea of a driving test at age 70 and, to a lesser extent, by the finding that almost a third of them confessed that they now felt less confident on the roads than they used to. A useful way forward would be to explore ways of giving useful feedback to older drivers, especially in respect of skills that may otherwise be deteriorating without their awareness: for example, deterioration of scanning patterns and failures of vigilance. An obvious problem with any additional, 'prosthetic' 'feedbackgiving' device that we might suggest for everyday use by older drivers is that they would only offer yet another source of information for overloaded older drivers to monitor. With the steadily increasing information demands of modern traffic situations, and increasing evidence of the role of information overload as a factor in accidents in which older drivers are involved, this is Applied Ergonomics 1994 Volume 25 Number 1

The problems of being an older driver: C A Holland and P M A Rabbitt

obviously to be avoided. A possible answer is suggested by Duncan et al's (unpublished) finding that novices who had been driving for less than one year were actually better than experienced motorists in terms of skills that require feedback for their competent maintenance. In practice, the simplest and most effective course may be to give older people feedback for a limited period during training sessions with a skilled observer or driving instructor. Older people do not seem to be aware that their reduced information-processing capacity and speed of processing information make particular categories of traffic situations especially dangerous for them. It seems important to supplement their failures of self-monitoring by externally provided monitoring and feedback so as to provide them with the information that they require, in order to give them incentives to change their behaviour, and to advise them on the particular adaptations that they may need to make in order to continue to drive safely.

Acknowledgements The above research was supported by G r a n t N u m b e r 8ZC15 from the General,,Accident Insurance Company and the Economic and gudal Research Council, UK. The authors would like to thank Mr G r a h a m Fryer, editor of the Association of Driving Instructors' magazine, for his interest and assistance.

References AA Foundation 1988 Motoring and the older driver AA Foundation for Road Safety Research, Basingstoke, Hampshire, UK Bali, K K, Beard, B L, Roenker, D L, Miller, R L and Griggs, D S 1988 'Age and visual search: expanding the useful field of view' J Opt Soc A m 5 (12) 2210-2219 Broughton, J 1988 The variation of car drivers' accident risk with age T R R L Digest RR135, Transport and Road Research Laboratory, Crowthorne, UK Cerella, J 1985 'Information processing rates in the elderly' Psychol Bull 98, 67-83 Connolly, S A V and Holland, C A 'The effect of cognitive functioning on walking in healthy elderly and stroke patients' Unpublished Critchley, M 1956 'Neurologic changes in the aged' J Chronic DIS 3, 459-477 Duncan, J, Williams, P and Brown, I 'Components of driving skill: experience does not mean expertise' Unpublished

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Hakamies.Blomqvist, L 1988 'Fatal road accidents involving elderly drivers' Paper presented at the Commission of the European Communities Workshop on Errors in the Operation of Transport Systems, Cambridge Harteman, F 1981 Los accidents mortels en 1980 Peugot SA/ Renault, Laboratoire de Physiologic et de Biomecanique Hauer, E 1988 'The safety of older persons at intersections' in Transportation in an ageing society, Vol 2, Improving mobility and safety for older persons TRB, NRC, Washington, DC, USA Hills, B L and Burg, A 1977 A re-analysis of California driver vision data: general findings TRRL Digest LR768, Transport and Road Research Laboratory, Crowthorne, UK Holland, C A and Rabbitt, P M A 1990 'Autobiographical and text recall in the elderly: an investigation of a processing resource deficit' Q J Exp Psycho142A, 441-470 Holland, C A and Rabbitt, P M A 1992 'Old people's awareness of their sensory and cognitive defects and the implications for road safety' Appl Cogn Psychol 6, 217-231 Malfetti, J and Winter, D 1987 '"Safe" and "unsafe" performance of older drivers: a descriptive study' AAA Foundation for Traffic Safety, Falls Church, VA, USA McFarland, R A and Fisher, M B 1955 'Alterations in dark adaptation as a function of age' J Gerontol 10, 424-428 Moore, R L, Sedgely, I P and Sabey, B E 1982 Ages of car drivers involved in accidents, with special reference to junctions TRRL Supplementary Report 718, Transport and Road Research Laboratory, Crowthorne, UK Nantamen, R and Summala, H 1976 Road user behaviour and traffic accidents North-Holland, Amsterdam OECD and WHO 1986 Traffic safety of elderly road users Road Transport Research, Paris Rabbitt, P M A 1990 'Age, IQ and awareness and recall of errors' Ergonomics 33 (10/11), 1291-1305 Rabbitt, P M A and Abson, V 1990 'Lost and found: some logical and methodological limitations to self report questionnaires as tools to study cognitive ageing' Br J Psychol 81, 1-16 Rumar, K 1986 'Age and road user behaviour' Fourth Nordic Congress of Traffic Medicine Salthou~, T A 1985 A theory of cognitive aging NorthHolland, Amsterdam Schmidt, U, Brendemuhi, D, Schenk, N and Engels, K 1989 'The driving behaviour of elderly motorists'Paper presented at the Paris Conference on Road User Behaviour Staplin, L K, Breton, M E, Haimo, S F, Farber, E I and Byrnes, A M 1990 'Age-related diminished capabilities and driver performance' Federal Highway Administration working paper, McLean, VA, USA Stollery, B T, Rabbitt, P M A and Moore, B J 1990 'Speed and concentration in healthy old age' paper presented at the Third Cognitive Aging Conference, Atlanta, Georgia Summala, H and Koivlsto, I 1989 'Unalerted drivers' brake reaction times: older drivers compensate for their slower reactions by driving more slowly' paper presented at Paris Conference on Road Safety

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