Targeting high-risk groups of drivers
Adolescent drivers and elderly drivers
2
Drivers killed/injured pr. million km driven
0,00
0,10
0,20
0,30
0,40
0,50
0,60
0,70
0,80
0,90
1,00
18-19 20-24 25-34 35-44 45-54 55-64 65-74 75+
Menn 2001
Kvinner 2001
Bjørnskau, 2004
3
0
10
20
30
40
50
60
70
80
90
100
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
Proportion of drivers 65 year of age and older with a driver license – 1980-2002 (Norway)
4
Characteristics of accidents with older drivers• Overrrepresented in junction accidents, especially
when turning left (in countries with right-side driving).
• Higher accident risk in roundabouts• Overrepresented in wrong-way driving accidents• Elderly have problems reading signs on distance,
especially at nighttime and under glare conditions• Signs often have too short sight distance to have
enough time to perceive and react
5
Characteristics of older drivers – age related changes:
- Visual and auditory functions impaired
- Cognitive ability can be impaired – e.g. reduced perception, attention and information processing
- Physical ability reduced (stiffer neck, torso, reduced muscle power)
- More health problems and more use of medication
- However – large in-group variation – an older driver is not necessary a bad driver
6
On the other hand, elderly drivers:
– are usually very safety oriented (few violations)
– have a defensive driving style– tend to compensate for their impairments by:
– avoiding heavy traffic– driving at night-time/evening– avoiding driving on slippery roads and during difficult
weather conditions– using passengers as “co-pilots”
– Many elderly drivers may therefore be the safest drivers
– Reason to believe that certain subgroups of elderly drivers accounts for the increase in risk
7
• Weak association between visual acuity (synsskarphet) and accident risk– Due to compensation?
• Reduced visual acuity under glare conditions associated with a poor driving performance (indikasjon på grå stær/cataract)
• Defects in the central field of view also associated with poor driving performance
• Neither of these two tests are included in the medical test older drivers have to pass today
Ulleberg og Sagberg, 2003
Subgroups with functional impairments -vision
8
Reduced acuity under glare conditions
9
Defects in the central field of vision may impair perception
Moderate defect Severe defect (extreme example)
10
Amsler grid – indication of defects in the central field of view
- Focus on the dot in the middle
- Breaks/waves in the grid indicate defects in the central field og vision
11
Attention and accident risk are related• UFOV (”useful field of view”)
– Slow information processing – Impaired divided and selective attention– Low capacity of using information in the
peripheral field of view.
• Other cognitive impairments typical for dementia related to accident risk – Short time memory, spatial orientation,
change of attention and being able to concentrate over time
12
Holistic approach to safety promotion for older drivers
The road infrastructureThe driver
The vehicle
Training
Selection/screening
Improve functional ability
Reduce mental workload and (consequenses) of driver error
Reduce injury if an accident occurs
Reduce mental workload and driver errors
Reduce injury for drivers, pedestrians and cyclists
13
Examples of road design for elderly drivers• The system is today primarily
designed for the young and healthy driver
• A road system designed for the older driver may improve safety for all drivers
14
Example – Avoidance of junction accidents
Main idea: lowering information processing demands (less mental workload)
– simplify junctions (e.g. from X- to T-crossing)– left-turn lane and own signal-light phases for left turns– road illumination at junctions and pedestrian crossings– increase size and conspicuity of signs and other
information– Increase time from information is presented to the
driver has to respond (more than 2.0 sec)
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Example: wrong way driving on motorway
16
Correct direction
Wrong way!Planned direction
Hvam-junction
17
Several factors complicating the information processing at Hvam
• Several roundabouts near each other• Information overload concerning signs• Contra-intuitive direction of on-ramp
(more natural to believe that the wrong ramp is the correct one)
• On-ramp placed in connection to roundabout
• All these elements should be avoided
18
Typical driver error resulting in wrong way driving from service areas
Gas station
19
Better solution?• Simplify the driver’s decision
making Curve signal that this is an unnatural way to enter
20
Avoiding errors and reducing injury through special vehicle design for older drivers• Several types of equipment may reduce
workload and help reduced motoric skills– Existing: Power steering, power brakes,
automatic gearing– Soon to come: night-time vision, collision
avoidance systems (but uncertain effect)– Several passive safety measures are today
unsuited due to higher fragility among elderly drivers: airbags too powerful, seat belts may cause injury
21
Possible explanations for young drivers elevated accident risk
More errors and slips/lapses?
– inexperienced, driving skills are not automatized– low spare mental capacity when driving– hazards not perceived adequately
More violations?- ”Poorer” attitudes– More preferences towards risk-taking?– More social pressure towards risk-taking?
The answer seems to be ”yes” to both explanations
22
The accident risk is reduced by 50 % during the first 9
months
Sagberg, 2002
23
Same tendency for all age groups
Violations?
Experience, less errors?
Maycock, 1991
24
What happens during the first nine months?
• Routine behaviours get automatised(are performed without conscious attention)
• Increased spare mental capacity for handling unexpected events
• Consequences: Technical skills improve, fewer slips & lapses and errors
• Hazard perception improves (faster & better)
Sagberg og Bjørnskau, 2003
25
• Also: Learning to interact better with other drivers – being more predictable for others
• Interestingly: more violations (!), especially running yellow lights, more “offensive” driving like less hesitation at junctions etc.
26
The experience paradox
• Most important experience must be gained during the most dangerous period of a driver’s development (i.e. first year holding a driver license)
• How can this experience be gained in a safe way?
27
Driving with a lay instructor and accident risk after licensing
0
20
40
60
80
100
0-4 turer 5-10 turer 11-25 turer 26-50 turer Mer enn 50 turer Trips with lay insructor
Acc.involved drivers
pr. million km
1-6 months after 7-17 months after
Sagberg, 2002
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• However – even though the accident risk is reduced after nine months, it is still high compared to more experienced drivers
• Due to risk-taking? Safety motivation needs to be addressed
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Improved skills and lowered safety motivation
0
10
20
30
40
50
60
70
80
1mnd 5 mnd 9 mnd 1 år
Technical skills Safety orientationSummala, 1996
High
Low
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Not all young drivers are high-violators
Risk Group (males/females)
High Social deviant (80/20)
Hostile (45/55)
Medium Adventure seeking (50/50)
Indifferent (55/45)
Low Considerate (40/60)
Worrying (80/20)
Ulleberg, 2002
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Personality traits and driver behaviour
Two ”problem groups” of young drivers
Ulleberg, 2002
Low anxiety
High sensation seeking
Mild social deviance
Egocentric
Cluster 2
High anxiety
High aggression
Hostile
Impulsivity
Cluster 5
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Response to a traffic safety campaign by cluster
3,5
4
4,5
5
5,5
6
Cluster 1 Cluster 2 Cluster 3 Cluster 4 Cluster 5 Cluster 6
Mea
n sc
ore
Females
Males
Ulleberg, 2002
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Why are risk-takers so difficult to influence?Rejection - does not elaborate the message• Affect and hedonism – does not like the message,
too much in conflict with own preferences – the processes of contrasting and rejection– No personal relevance - No.1 attitude: ”I have such good
driving skills that I can take more chances than others” (meaning: the message does not apply to me)
– Low preferences for elaborating messages in general (are they bit stupid…?)
Reckless driving seems to be a very important part of their identity (and reflection of their personality). Difficult to change people’s lifestyle through an attitude campaign
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Influencing adolescents through campaigns
• Advantageous to let adolescents perceive that they themselves take decisions about attitude/behavioural change. Do not tell them directly how to think and behave!
• Self-initiated decisions usually motivate for deeper elaboration of the message, which may facilitate attitude/behaviour change
• Adolescents are more easily influenced by social and group pressure. Face-to-face communication most efficient. Especially from other adolescents
• New campaigns tries to motivate adolescents to influence each other – e.g. passengers influencing the driver. E.g. “Sei I frå!” campaign
• Targeting night-time weekend driving and group pressure may be especially relevant
35
Risk of injury by time and day
MandagTirsdag
OnsdagTorsdag
FredagLørdag
Søndag
00-06
06-12
12-18
18-24
0
2
4
6
8
10
12
Bjørnskau, 2004
Reducing exposure at night-time in weekends especially relevant
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Relativ risk of fatal accidents pr. 10 mill. trips
0
0,5
1
1,5
2
2,5
3
3,5
No passengers 1 passenger 2 passengers 3 passengers
Increase in accident risk when young drivers carry young passengers
Chen, 2000
Focus on positiv guidance from passengers, reduce group pressure especially relevant
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Other possible measures
• Restriction of night-time driving and carrying young passengers for young drivers (implemented in several countries)
• Alternative modes of transport more easily available (e.g. cheap taxis during weekends)
• More driving at motor sport lanes? Supposed catharsis-effect, but may have the opposite effect on safety due to compensation (increased belief in own driving skills)
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Model illustrating factors influencing young drivers driving behaviour and accident involvement
Learning-process
”Backpack”Social influence and individual differences
Driver education
Training
Expereince
Personality Lifestyle Group norms Cognitive and motoric skills
Perceived risk of accidents
Actual driving skills
Perceived driving skills
Automatization of the driving process
Decision making
Motives
Attitudes
Driving behaviour:
Slips and lapses
Errors
Violations
Modified model based on Gregersen og Berg, 1996
