Assessing the driving performance of
older adult drivers:
on-road versus simulated driving
Author: Hoe C. Lee, Don Cameron, Andy H. Lee
Accident Analysis and Prevention 35 (2003 797-803)
Reporter : Yang Kun Ou
Purpose
• To validate a laboratory-based driving simulator
in measuring on-road driving performance
• The results supported the validity of the driving
simulator and it is a safer and more economical
method than the on-road testing to assess the
driving performance of older adult drivers
Reference
• Summala (1988) concluded that such measures
are confounded by age, therefore, fail to reflect
the actual cognitive and/or physical deficits of
older drivers
• Many studies have concluded that driving
simulators can provide accurate observations
on drivers’ behaviors and functions (Alicandri, 1994;
Fraser et al., 1994; Van der Winsum, 1996; Desmond and Matthews, 1997;
Ellingrod et al., 1997; Van der Winsum and Brouwer, 1997)
Reference
• Simulators have recently been used to study
the driving behaviors of Alzheimer patients
(Rizzo et al., 2001).
Methods
• Participants
– Included 129 participants (78% is male )
– The sample age ranged from 60 to 88 years (mean
= 72.9, S.D. = 7.1)
– valid driving license and not having incurred five
or more demerit points in the past 2 years
Procedure
• Assessment of each individual took
approximately 2.5 hour
–
–
–
–
orientation,
45-min simulated driving session
40 min of on-road testing
post-assessment questionnaire survey
Procedure
• The STISIM driving simulator used to study
the behaviors of the participants in a simulated
driving environment. (Fig. 1.)
• The simulator was programmed so that
participants had to perform driving tasks
involving different traffic scenarios, specially
designed to investigate their road knowledge
and cognitive/perceptual skills related to the
known attributes of safe driving.
Fig. 1. A participants being assessed by the STISIM driving simulator
Procedure
• A set of 10 simulated assessment criteria was
developed to gauge driving performance
• These desirable driving behaviors were
defined with reference to the current licensing
standard in Western Australia.
Assessment criteria
Description of the traffic scenarios and task
required to perform by the participants
Desirable driving behaviors (score).
Road skills
Rule compliance
Double lanes road, where participant’s car was on the right
lane. KEEP LEFT signs displayed every 50m to prompt
participants to go back to the inner lane.
TASK: Lane changing
Follow “keep to left ‘’ rule;
voluntarily (2)
with visual prompt (1)
check traffic by head turn (1)
with rear mirror (1)
proper use of indicators (1)
Traffic sign compliance
Driving through STOP, GIVE WAY and pedestrian crossings.
TASK: drive through the scenarios safely
Approach slowly (1)
stop in right place (1)
give way as required (1)
proceed when opportunity comes (1)
correct use of indicators (1)
check mirror before proceed (1)
Driving speed
Double-lanes straight road, 60 km/h speed limit. TASK: drive
2 km along the road according to the designated speed
Speed (2 km/run time of the distance)
Use of indicator
Road work blocking the road.
TASK: drive around the obstacles and return to the inner lane
as soon as possible
Signal to the right and left to change lane (2, one
each)
check traffic (1)
voluntarily return to inner lane (1)
Road use obligation
T-junctions leading to main road with STOP signs.
TASK: observe traffic conditions and drive through safely
Approach with caution and slow down (1)
indicate right or left turn (1)
proceed when has opportunity (1)
check traffic with head turn (1)
rear mirror (1)
use of indicators (1).
Assessment criteria
Description of the traffic scenarios and task
required to perform by the participants
Desirable driving behaviors (score).
Cognition/perceptual
Decision & judgement
Pedestrians 25m ahead running across the road
hastily, car parking on the roadside move out without
signalling and car in front suddenly slow down.
TASK: avoid crashing
One mark for each success in avoiding
accident when confronted with simulated
dangerous driving scenarios.
Working memory
Five street names and five manoeuvres (turn left or
right) marked on a route of road map to a fictitious
park.
TASK: remember the names and the manoeuvres in 5
min and recall them after 10 min simulated driving
Names and manoeuvres recalled (1 for
each correct answer, up to 8)
Sequence of manoeuvre (3, in perfect order;
2, 2–3 correct; 1, 1 correct and 0, none).
Multi-tasks
Fifteen billboards with “SUBSTRACT” sign were
posted along the road.
TASK: starting from 100, take away “5” every time
the “SUBSTRACT” billboard comes out
Correct answer (1)
Confidence on high
speed
Speed limits (60, 70 and 110 km/h) vary according
traffic conditions.
TASK: observe and maintain a speed close to the
speed limits
Number of tokens received when the
driving speed is close to the designated
speed (±5 km/h)
Attention task
“Diamond” shapes on the top corners of simulator
screen change to “triangle” randomly.
TASK: engage the “turn” indicator in response to the
visual stimulus
Correct responses
Procedure
• On-road assessment criteria were devised to
measure driving performance
• The current licensing procedure and standard
of Western Australia were adopted.
Assessment criteria
Observations of the participants
Desirable driving behaviors (score).
Road use obligation
Driving manoeuvres in seven
roundabouts
Being certain of obligation, proceeded when has opportunity to do,
gave appropriate signals, gave signal not too short or long, did not give
wrong signal.
Traffic sign compliance
Manoeuvres through four pedestrian
crossings, with a “10 km/h” speed
control sign and a speed bump
Was able to slow down in approaching the crossing, did not stop when
it is not necessary, did not hit the speed bumps, gave way to
pedestrians crossing and compiled with the 10 km/h rule.
Traffic light
Manoeuvres before and through traffic
lights
Did not stop in wrong position, did not stop when not necessary, did
not start before signal turns green, did not proceed on amber when
could have stopped safely, did not proceed on red signal, did not cross
continuous white line and did not fail to notice lights.
T-junction
Manoeuvres before and through Tjunctions
Did not approach intersection too slowly, did not brakes or swerves at
last minute, did not approach intersection too fast, looked both ways in
approaching intersection, did not proceed if way is not clear,
proceeded when has opportunity to do, would give way (right hand
rule), did not turn across oncoming traffic, did not swing too wide on
corner, did not cut corner, did not swing too wider on corner and did
not turn across oncoming traffic.
General driving skill
The steering and breaking behaviour
throughout the assessment
Did not perform erratic movement of the steering wheel, did not put
arm and elbow out of window, did not allow steering wheel to self
centre, did not incorrectly position of their hand, did not do
unnecessary on hand drive, did not depress clutch before brake in high
gear stopping, did not stop too far from given mark, did not stop too
suddenly, did not stop too slowly in quick stop test and did not stall
engine.
Assessment criteria
Description of the traffic scenarios and task
required to perform by the participants
Desirable driving behaviors (score).
Normal driving
General driving behaviour throughout the
experiment
Kept to left, drove with reasonable speed, did not drive
on erratic speed, did not take erratic course, used rear
view mirror frequently, did not exceeds speed limit, did
not follow closely to the front car, did not overtake
unnecessarily, did not over the centre line overtaking.
Error detection
Awareness and sensitivity of participants in
finding out they had made mistakes
Noticed in a wrong place at once, noticed in a wrong
place until drive for more than 10 m, did not need to be
told that a mistake had been made, checked traffic and
rectified the mistake by doing a U-turn safely.
Error recovery
Driving behaviours when participants tried
to rectify mistakes committed
Did not do a hasty U-turn without observing the traffic,
knew what to do and require no verbal prompting to
rectify the error, checked other traffic by turning head,
signal to indicate intention in about turn, looked to rear
either directly or in mirror.
Use of indicator
Correct use of indicators throughout the
assessment
One point for each correct use of indicators.
Driving speed
Speed of the car driving through a 500m
segment of straight road (70 km/h)
The distance divided by run time
Working memory
Participants’ ability to remember the test
route
One point was deduced if participant ask for directions
Ethical considerations
• Written consent was sought throughout the
process and confidentiality of records was
maintained.
• All participants were informed that they were
free to terminate the study at any time without
any negative consequences
Result
• Driving information
– Of the 129 participants, 70% wore spectacles
during the assessment
– Approximately 12% of the participants had been
employed in occupations which involved driving a
vehicle regularly, such as courier workers, taxi or
truck drivers, prior to retirement.
– The estimated driving time per week ranged from
1 to 35 h (mean = 11, S.D. = 8.35)
Result
• Eleven participants (9%) reported a mild
degree of dizziness after completing the
simulated driving assessment.
• Such feeling of dizziness only lasted for a
short time and did not appear to affect the
subsequent on-road test
Analysis of simulated driving and road
assessment criteria
• The measurement properties of the assessment
criteria were examined by reliability analysis
• The Cronbach alpha coefficients were 0.7 and 0.8 for
simulated driving and on-road driving variables,
respectively, confirming the internal consistency of
the scales that comprise the two measures of driving
performance.
• An inspection of Pearson correlations revealed that
the assessment criteria were highly correlated within
each setting, with r as high as 0.8 between some
variables
Analysis of simulated driving and road
assessment criteria
• Simulated Driving Index
= −0.26 attention task − 0.38 rule compliance
−0.36 road use obligation
−0.38 decision and judgement
−0.36working memory − 0.40 use of indicator
−0.21 multi-tasks − 0.18 driving speed
−0.14 confidence on high speed
−0.36 traffic sign compliance
Analysis of simulated driving and road
assessment criteria
• Road Assessment Index
= 0.28 error detection + 0.15 error recovery
+0.36 general driving skill + 0.3 normal driving
+0.39 road use obligation
+0.27 traffic sign compliance
+0.22working memory + 0.39 use of indicator
+0.31 driving speed + 0.36 T-junction
+0.16 traffic light
Relationship between the performance
indices
• the Simulated Driving Index was positively
associated with the Road Assessment Index,
with r = 0.716.
• Over 65.7% of the variability in the Road
Assessment Index can be explained by the
Simulated Driving Index, after accounting for
age and gender, though the latter appeared to
be non-significant.
Plot of road assessment index against simulated
driving index
Relationship between the performance
indices