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Development and validation of a self-report
measure of bus driver behaviour
Lisa Dorn (1)
Lucy Stephen
Anders af Wåhlberg (2)
and
Julie Gandolfi
1. Department of Systems Engineering and Human Factors,
Cranfield University,
Cranfield,
Bedfordshire, MK43 0AL
UK
e-mail: l.dorn@cranfield.ac.uk
2. Department of Psychology
Uppsala University
P. O. Box 1225
751 42 Uppsala
Sweden
e-mail: anders.af_wahlberg@psyk.uu.se
Corresponding Author:
Dr Lisa Dorn
Ergonomics, Volume 53, Issue 12, 2010, Pages 1420 - 1433
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Abstract
There are likely to be individual differences in bus driver behaviour when adhering to strict schedules under
time pressure. A reliable and valid assessment of these individual differences would be useful for bus companies
keen to mitigate risk of crash involvement. This paper reports on three studies to develop and validate a self
report measure of bus driver behaviour. For Study 1, two principal components analyses of a pilot questionnaire
revealed six components describing bus driver behaviour and four bus driver coping components. In Study 2,
test-retest reliability of the components were tested in a sub-sample and found to be adequate. Further, the ten
components were used to predict bus crash involvement at three levels of culpability with consistently
significant associations found for two components. For Study 3, Avoidance coping was consistently associated
with celeration variables in a bus simulator, especially for a time pressured drive.
Key words: bus driver, traffic safety, crash, driver behaviour
Relevance for Ergonomics Research and Practice
The instrument can be used by bus companies for driver stress and fatigue management training to identify at
risk bus driver behaviour. Training to reduce the tendency to engage in avoidance coping strategies, improve
evaluative coping strategies and hazard monitoring when under stress may improve bus driver safety.
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INTRODUCTION
It has been well documented that bus driving can be a highly stressful occupation (Bartone,
1989) resulting from high and conflicting demands and lack of control over work pace and
driving situations (Evans and Carrere., 1991; Carrere et al., 1991; Evans., 1994). Factors
intrinsic to the job such as time pressure, long shifts and responsibility for passenger safety
can all contribute to bus driver stress. Apart from its toll on health and well being at work
(Taylor and Dorn, 2005) there is also good reason to suppose that bus driver stress and
fatigue may be lead to an increased risk of being involved in a bus crash (Greiner et al.,
1998). Driver stress may impair performance, or distract the driver from maintaining safety
through potentially dangerous coping strategies such as reacting aggressively to other traffic
or engaging in self-distraction.
One way of measuring emotional reactions to driving is with the use of the Driver
Stress Inventory's (DSI: Matthews et al., 1996; 1997) five scales of Aggression, Dislike of
Driving, Hazard Monitoring, Thrill Seeking and Fatigue Proneness. The DSI scales have
been found to be associated with self reported crashes (Matthews et al., 1991) and violations,
performance decrements and/or risk taking amongst both commuter drivers (Dorn and
Matthews, 1995) and professional drivers (Öz et al., 2009; Kontogiannis, 2006; Dorn, 2005)
and correlated with different aspects of simulated driving behaviour in an expected direction
according to the transactional theory of driver stress (Matthews et al., 1998).
The transactional theory of driver stress (Matthews, 2002) predicts that personality
factors interact with situational traffic demands to elicit cognitive processes that mediate the
effects of driver stress vulnerability on both subjective outcomes (e.g., emotional distress)
and objective behavioural outcomes dependent upon specific stress responses. For example,
Dislike of Driving is associated with tense moods and a perceived lack of control and is
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associated with driver error, whereas Aggression is associated with risk taking, anger and
negative appraisals of other drivers.
Coping with driver stress as measured via the Driver Coping Questionnaire‟s (DCQ)
(Matthews et al., 1997) reveals five distinct driver coping strategies based on original coping
research by Lazarus and Folkman (1984). Task-focused Coping involves active attempts to
increase vigilance when driving is difficult or demanding (Matthews et al., 1998).
Reappraisal measures the extent to which the driver evaluates what mistakes were made
(Matthews et al., 1998). Emotion-focused Coping involves a strategy whereby the driver
ruminates over their performance and self-blames for the difficulties they encounter. This
behaviour appears to distract drivers from the primary task of driving safely (Matthews and
Wells, 1996). Confrontive Coping involves the mastery of traffic through self-assertion or
conflict (Matthews, 2001). Finally, Avoidance Coping was originally described by Cox and
Ferguson (1991) as a strategy whereby the driver attempts to ignore the stressor most
frequently through self-distraction and is associated with reduced attention to the driving task
(Matthews et al., 1998). The latter three coping styles are maladaptive responses to driver
stress. Machin and Hoare (2008) showed the importance of ineffective coping on negative
outcomes with maladaptive strategies of Confrontive and Avoidance Coping explained some
of the relationship between bus driver workload, negative affect and physical symptoms.
Both the DSI and DCQ were developed on commuter drivers and do not take into
account the specific risks of driving a bus for work. Developing an instrument to measure bus
driver behaviour based on the DSI and DCQ foundation may be a useful tool for bus
companies when assessing safety intervention effectiveness, monitoring driver behaviour
over time as part of a risk management programme, or in the selection, recruitment and
training of bus drivers. Such an instrument can be used to identify the behavioural responses
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that can increase the risk of bus crashes and/or lead to poor health outcomes through
ineffective coping strategies.
Research to develop a self-report measure of bus driver behaviour began by
understanding whether the original DSI component structure could be replicated for a bus
driving sample. A slightly modified version of the DSI was administered to 543 UK bus
drivers and an exploratory Principal Components Analysis (PCA) was performed (Garwood
and Dorn, 2003). The results indicated minor differences between the component structure
for commuter drivers and bus drivers for both the DSI and the DCQ. For the DSI, all five
components were replicated with the exception being that Thrill Seeking and Dislike of
Driving were reversed in their loadings but retained the original items. The DCQ also
indicated considerable overlap with all five original components being replicated. The study
confirmed the robustness of the original DSI and DCQ component structure in defining bus
driver behaviour. Garwood and Dorn (2003) point out that even though the component
structure for the DSI and DCQ had been replicated for bus drivers, there were likely to be
many issues pertinent to the demands of bus driving not currently included in either
instrument.
Bus driving can be differentiated from commuter driving in several ways; bus driving is
paced to a strict schedule; requires frequent stopping and starting; involves interaction with
the general public and mostly takes place in busy built-up areas. However, there are also
similarities in responses to traffic independent of the work context given that most drivers,
professional or otherwise, report some element of vulnerability to driver stress (Öz et al.,
2009). Building on their work, Dorn and Garwood (2005) conducted in-depth interviews with
bus drivers to generate items relevant to bus driving which formed the basis of a pilot
