Investigation of Road Crossing Behaviour of Older Pedestrians
Monash University Accident Research Centre - Report #81 - 1995
Authors: J. Oxley, B. Fildes, E. Ihsen, R. Day & J. Charlton
Full report in .pdf format [7.5MB]
Road safety literature suggests that the oldest road users have a high accident risk and that they are much more likely to be severely injured or killed once involved in an accident than any other group of road users. There is also considerable evidence that older people experience deficits not only in their physical abilities but also in sensory, perceptual, and cognitive abilities. Little is known, however, about how these affect road-crossing behaviour and their safety. The purpose of this study was to investigate the road-crossing behaviour of both old and young adult pedestrians to determine whether older pedestrians behaviour was more risky than that of younger pedestrians. The study also aimed to identify target groups and road situations for intervention and to recommend countermeasures designed to reduce the frequency and severity of older pedestrian accidents. Road crossing behaviour of older and younger pedestrians was filmed at two two-lane undivided road strip shopping centre sites, and at one four-lane divided road strip shopping centre site in the Melbourne metropolitan area. Individual road-crossings were filmed unobtrusively from a parked van in which two cameras were set appropriately to record both oncoming near-side traffic and pedestrian movements. Pedestrian behaviour was scored for a number of determinants of safe road crossing actions. Significant differences were observed between young and old pedestrian road crossing behaviour on a number of critical key variables. Overall, the results show that older pedestrians' road crossing behaviour in complex traffic situations was less safe than their younger counterparts. In less complex situations, older pedestrians behaviour was more like that of younger pedestrians. The findings are discussed in relation to age-related sensory, perceptual, cognitive and motor changes and recommendations for countermeasures and further research are made.
The road safety literature shows that older people are over-involved in pedestrian crashes and more likely to be severely injured or killed than younger pedestrians. There is evidence that older people experience declines in their physical, sensory, perceptual and cognitive abilities. Little research, however, has been conducted examining the extent to which age-related mobility and/or sensory or motor deficits affect their road crossing behaviour and whether they are able to adopt compensatory behaviours to overcome these disabilities.
This study set out to investigate the road crossing practices of older people, relative to younger ones in order to show whether they experience particular problems crossing the road and whether their road crossing behaviour rendered them more vulnerable to accidents. The study aimed to explain how their sensory, motor or perceptual deficits might influence road crossing practices among the elderly, to identify opportunities for behavioural intervention to reduce the frequency and/or severity of older pedestrian accidents, and highlight areas where additional research may be required.
The method adopted for this study involved "black-spot" analysis of older pedestrian crashes as well as observational studies of road crossing practices. Behaviour was filmed at a number of locations in and around Melbourne and scored relative to younger pedestrians and traffic conditions. These findings are discussed in terms of actions that might put older pedestrians more at risk of crash involvement and what could be done in terms of publicity, education, enforcement and engineering to reduce these risks.
A "black-spot" analysis of police reported pedestrian accidents was conducted at several locations in and around Melbourne where older pedestrians were involved in road crashes to highlight the types of crashes that older (and younger) pedestrians were having. It revealed that the majority of road crossing accidents occurred as pedestrians stepped off the kerb, often as they walked out behind parked cars and into the path of oncoming vehicles. Older pedestrians, too, were involved in a number of far-side collisions, indicating that they might have been caught out by traffic while crossing the road. From this analysis, a number of specific road crossing actions were identified that were worthy of closer investigation.
A pilot study was first conducted to develop a suitable method for collecting these data and to identify relevant independent variables and measures. Unobtrusive filming of road crossing behaviour was conducted from a van parked on the side of the road and set up with two cameras to provide simultaneous video images of oncoming traffic and pedestrian movements.
Two observational studies were then undertaken at strip shopping centres frequented by young and old pedestrians. The first study involved two-way traffic on an undivided roadway while the second focussed on one-way traffic and divided roads. Behaviour was scored leading up to and crossing the road itself in terms of times taken and looking behaviour.
Two-way Roads - Complex Environment
Differences were observed in times spent waiting and leaving the kerb and crossing two-way undivided roads illustrating that older people take longer to execute these actions than younger people. There were significant differences in looking behaviour while crossing the road where older people were more focussed on their walking track and less on the near- and far-side traffic. The longer period spent crossing the road inevitably means that older pedestrians are more exposed to the likelihood of an accident.
Their road crossing behaviour forced them to interact with the traffic more often in these environments. Given their diminished motor skills and ability to react quickly to danger, this means that these older people are less able to take evasive action and hence more vulnerable in dangerous road crossing situations.
Comparing road crossing times with time of arrival of vehicles in the near-side lane showed that while the majority of older (and younger) pedestrians crossed the road safely, slower younger walkers tended to over-compensate in their crossing judgements while slower older pedestrians under-compensated. This demonstrated that older people do not adequately adjust for their physiological and psychological declines when crossing the road.
It was argued that crossing a two-way undivided road is a complex multi-task skill requiring a high level ability to integrate multiple sources of information simultaneously. The findings from this study seemed to suggest that the reduced cognitive abilities associated with the ageing process may penalise older pedestrian judgements, placing them more at risk of a collision when crossing the road.
One-way Roads - Less Complex Environment
The effect of reduced cognitive abilities through ageing and its likely effects on road crossing behaviour of older pedestrians was examined further in a second observational study involving one-way traffic and divided roads. It was expected that in these less complex settings, older pedestrians would behave more like younger pedestrians.
Indeed, the findings confirmed that older pedestrian behaviour improved when crossing one-way roads. Road crossing and time of arrival plots were quite similar for both old and young pedestrians. There were practically no differences in judging when to cross the road between faster and slower pedestrians in both groups, clearly demonstrating the benefits of simplifying the task for the aged as well as all pedestrians.
There were still differences, though, in the time to cross and looking behaviour while crossing between young and old pedestrians. The elderly still took roughly twice as long to cross the road as their younger counterparts and were much more focussed on the road surface immediately ahead of them (their tracking path across the road).
Both groups spent considerably less time looking at the far-side traffic appearing to cross one road first and then the other. The presence of a median strip considerably simplified the road crossing task and was of particular importance for older pedestrians. There was a suggestion, however, that the attentional and search strategies of older people were still not optimal even in these more simple road crossing environments.
Summary of Problems Facing the Aged
The findings from these accident and observation studies can be summarised as follows:
- Older pedestrians took twice as long to assess the traffic and cross the road than younger adults.
- Older people spent more time looking at the ground on the approach to and while crossing the roadway and less time studying the traffic in near- and far-side lanes.
- While they spent more time deciding when to cross the road, older people often found themselves caught out in the traffic and vulnerable.
- They were more likely to be confused crossing the road in complex traffic situations where decisions involve the integration of multiple sources of sensory information.
- They were slow to react to approaching traffic.
- Slower, older pedestrians appeared to be particularly at risk crossing the road and appeared to be more confused than faster (more fit) elderly pedestrians.
- Older pedestrians often failed to compensate adequately for their reduced abilities.
- Older pedestrians failed to check and re-check traffic once they commenced their crossing and more commonly were forced to interact with the traffic around them.
- In less complex road settings, older pedestrian behaviour was more safe and more like that of younger pedestrians.
These findings have implications for road safety countermeasures aimed at the elderly. Suggested countermeasures would be most effective when linked appropriately and implemented in an integrated way.
These unsafe risky behaviours should be publicised widely to inform older pedestrians of actions that place them at risk of crash involvement and injury while crossing roads. Campaigns could also be aimed at improving driver awareness of older pedestrian limitations and difficulties. A number of specific messages stem from this research and these are outlined in the final chapter of the main report.
The findings from this study also have implications for training packages aimed at improving older pedestrian safety. Current packages such as "Walk-With-Care" which are used to alert older pedestrians to the dangers of using the road could incorporate many of these messages in their materials to help inform older people of their limitations and potential risk factors when crossing the roadway.
Laws and Enforcement
Several possible legal and/or enforcement measures are discussed in the final chapter such as a reduction of travel speed in high pedestrian areas, enforcement of crossing in appropriate places, awareness of current road laws and adherence to then and reduced or restricted parking provisions in areas commonly frequented by older persons. Many of these measures apply equally as well for pedestrians of all ages.
Traffic Engineering Solutions
While this study was primarily concerned with behavioural interventions, nevertheless, a number of engineering treatments are likely to have positive behavioural consequences and are listed here for completeness. These include the provision of median refuges and kerb extensions, more formal pedestrian crossings, barrier fencing to prevent crossings in high hazardous locations, and complete separation of pedestrians and vehicles in some areas.
Areas Where Further Research is Required
This study has identified a number of dangerous practices that older people tend to adopt when crossing the road and possible physiological and psychological causes for them. Gap acceptance, speed estimation and critical attentional cues were raised as key factors involved in safe road crossing behaviour on the road. Observational studies in themselves are not sufficient to explain fully the road safety consequences of deficits in these abilities and further detailed laboratory research is warranted to gain a full understanding and hence additional behavioural measures aimed at improving the safety of older pedestrians.
Sponsoring Organisation: Baseline Research Program - Department of Justice, Transport Accident Commission, Royal Automobile Club of Victoria (RACV) Ltd, VicRoads.