Crash characteristics of older pedestrian fatalities: Dementia pathology may be related to ‘at risk’ traffic situations Authors: Gorrie, C.A. Brown, J

Crash characteristics of older Crash characteristics of older pedestrian fatalities: Dementiapedestrian fatalities: Dementia

pathology may be related to pathology may be related to ‘at risk’ traffic situations‘at risk’ traffic situations

Authors: GorrieAuthors: Gorrie, , C.A. C.A. Brown, J. Phil Brown, J. Phil and Waite,M.E. and Waite,M.E.

IntroductionIntroduction

Older people (i.e. those over the age of 65 Older people (i.e. those over the age of 65 years) make up less than 13% of the years) make up less than 13% of the population yet account for about 32% of all population yet account for about 32% of all pedestrian deaths (ATSB, 2002a).pedestrian deaths (ATSB, 2002a).


While there has been an overall decrease in While there has been an overall decrease in pedestrian deaths per capita in recent years, pedestrian deaths per capita in recent years, the rate of decline varies by agethe rate of decline varies by age

For older pedestrians, the decline has been For older pedestrians, the decline has been significantly lesssignificantly less


The mortality rates for people over 65 years The mortality rates for people over 65 years exceed those for younger people for exceed those for younger people for comparative injury severity (McCoy et al., comparative injury severity (McCoy et al., 1989). 1989).

More older pedestrians die (44.6%) as a More older pedestrians die (44.6%) as a result of their injuries compared to 10.4% of result of their injuries compared to 10.4% of younger pedestrians (Sklar et al., 1989).younger pedestrians (Sklar et al., 1989).


the numbers of older pedestrians killed and the numbers of older pedestrians killed and injured can only be expected to grow given injured can only be expected to grow given the rapid ageing of the populationthe rapid ageing of the population

In NSW alone, there will be approximately In NSW alone, there will be approximately 1.8 million older people by 2041, which 1.8 million older people by 2041, which reflects a 144% increase since 1995 reflects a 144% increase since 1995 (Henderson and Jorm, 1998).(Henderson and Jorm, 1998).


Exposure of older pedestrians is also Exposure of older pedestrians is also influenced by the fact that walking is the influenced by the fact that walking is the primary mode of transport among many of primary mode of transport among many of these road users. these road users.

Keall (1995) reported that the percentage of Keall (1995) reported that the percentage of travel time spent walking is highest for travel time spent walking is highest for people over 65 years.people over 65 years.


A potential contributory role for cognitive A potential contributory role for cognitive decline in the behaviour of older pedestrians decline in the behaviour of older pedestrians has also been demonstrated in comparisons has also been demonstrated in comparisons of road crossing behaviour between older of road crossing behaviour between older and younger people (Oxley et al., 1997, and younger people (Oxley et al., 1997, 2001)2001)


Cognitive ability is known to decrease as Cognitive ability is known to decrease as part of neurodegenerative disease such as part of neurodegenerative disease such as Alzheimer’s disease.Alzheimer’s disease.

In Australia, approximately 6% of people In Australia, approximately 6% of people over the age of 65 years and nearly 25% of over the age of 65 years and nearly 25% of people over 85 years have diagnosed people over 85 years have diagnosed dementia (Henderson and Jorm, 1998)dementia (Henderson and Jorm, 1998)


There are many people diagnosed with mild There are many people diagnosed with mild cognitive impairment (MCI), who are cognitive impairment (MCI), who are functionally affected but do not meet criteria functionally affected but do not meet criteria for dementia for dementia (Busse et al., 2003; Fisk et al., 2003; (Busse et al., 2003; Fisk et al., 2003; Graham Graham et al., 1997; Ritchie et al., 2001).et al., 1997; Ritchie et al., 2001).


Mild cognitive impairment and Alzheimer’s Mild cognitive impairment and Alzheimer’s disease affect brain functions such as:disease affect brain functions such as:– complex attentional processescomplex attentional processes– secondary memorysecondary memory– accessing of word knowledgeaccessing of word knowledge– visuospatial abilityvisuospatial ability– some forms of abstract reasoning and problem some forms of abstract reasoning and problem

solving, some of which will be vital for safe solving, some of which will be vital for safe pedestrian behaviour.pedestrian behaviour.

MethodsMethods

Subjects Subjects 52 pedestrians (24M:28F) aged between 65 52 pedestrians (24M:28F) aged between 65

and 93 years (mean 77.7±7.3 years)and 93 years (mean 77.7±7.3 years) died following a vehicle–pedestrian crash died following a vehicle–pedestrian crash

between 1997 and 2003 in the Sydney between 1997 and 2003 in the Sydney metropolitan areametropolitan area

針對到院資料收集研究針對到院資料收集研究

ResultsResults

ResultsResults

ResultsResults

ResultsResults

ResultsResults

DiscussionDiscussion

The majority of older pedestrian crashes The majority of older pedestrian crashes occurred on dry fine weekday mornings, on occurred on dry fine weekday mornings, on straight sealed urban roads and close to the straight sealed urban roads and close to the person’s residenceperson’s residence

It is known that road crossing is a high-risk It is known that road crossing is a high-risk pedestrian activity, for people of all ages pedestrian activity, for people of all ages (Harruff et al., 1998).(Harruff et al., 1998).


42 (80.2%) of the pedestrians in this current 42 (80.2%) of the pedestrians in this current study were fatally injured while crossing the study were fatally injured while crossing the roadroad

Of particular concern was the relatively high Of particular concern was the relatively high number (27, 51.9%) of these older number (27, 51.9%) of these older pedestrians who were killed on or within pedestrians who were killed on or within 100m of a designated pedestrian crossing 100m of a designated pedestrian crossing while attempting to cross a road.while attempting to cross a road.


Although older pedestrians often report they Although older pedestrians often report they do not have enough time to cross at signal-do not have enough time to cross at signal-controlled traffic lights controlled traffic lights (Fildes (Fildes et al., 1994; Hoxie et al., et al., 1994; Hoxie et al., 1994; Langlois et al., 1997; Sheppard 1994; Langlois et al., 1997; Sheppard and Pattinson, 1986)and Pattinson, 1986)

Six of the eight crashes that resulted in a Six of the eight crashes that resulted in a fatality at traffic lights involved the pedestrian fatality at traffic lights involved the pedestrian crossing incorrectly against a red ‘don’t walk’ crossing incorrectly against a red ‘don’t walk’ signal.signal.


Sheppard and Pattinson (1986) have Sheppard and Pattinson (1986) have described how some older people with described how some older people with mobility problems have difficulty in walking mobility problems have difficulty in walking the extra distance to a designated road the extra distance to a designated road crossing facility.crossing facility.


Because older people have reduced walking Because older people have reduced walking speeds, compared to younger adults speeds, compared to younger adults (Job et (Job et al., 1992) al., 1992)

the time they are exposed to traffic while the time they are exposed to traffic while crossing a road is increasedcrossing a road is increased


Reduced cognition ability, as a result of Reduced cognition ability, as a result of ageing or because of a dementing disease, ageing or because of a dementing disease, is often cited as a possible contributing is often cited as a possible contributing factor in older pedestrian crashes factor in older pedestrian crashes (ATSB, (ATSB, 2002b; Fildes, 1998; OECD, 2001; Oxley, 2002; RTA, 2002b; Fildes, 1998; OECD, 2001; Oxley, 2002; RTA, 2002).2002).


a number of different traffic situations were a number of different traffic situations were examined to determine whether there were examined to determine whether there were any obvious links between those with any obvious links between those with moderate to high NFT score and moderate to high NFT score and involvement in particular crash situations.involvement in particular crash situations.


Compared to those with no or low NFT, Compared to those with no or low NFT, pedestrians with moderate to high NFT pedestrians with moderate to high NFT scores (III–VI) were more likely to be at scores (III–VI) were more likely to be at least partially responsible for the crashleast partially responsible for the crash

In other words, these pedestrians were In other words, these pedestrians were more likely to have behaved unexpectedly more likely to have behaved unexpectedly e.g. walked into the traffic, disobeyed a e.g. walked into the traffic, disobeyed a traffic signal etc.traffic signal etc.


pedestrians with higher NFTs were also pedestrians with higher NFTs were also more likely to be impacted by reversing more likely to be impacted by reversing vehicles as compared to pedestrians with vehicles as compared to pedestrians with lower NFTslower NFTs


It has previously been reported that It has previously been reported that cognitively normal older people have less cognitively normal older people have less ability to accurately judge safe gaps in which ability to accurately judge safe gaps in which to cross the road than younger adults (Oxley to cross the road than younger adults (Oxley et al., 1997) et al., 1997)

older adults tend to estimate time of arrival older adults tend to estimate time of arrival of a vehicle by distance rather than by of a vehicle by distance rather than by speed (Oxley, 2002).speed (Oxley, 2002).

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Crash characteristics of older pedestrian fatalities: Dementia pathology may be related to ‘at risk’ traffic situations Authors: Gorrie, C.A. Brown, J