Determinants of the occupational environment and heavy vehicle crashes in Western Australia: A case–control study

https://doi.org/10.1016/j.aap.2015.11.023Get rights and content

Highlights

  • Conflicting results regarding work environment-related factors and heavy vehicle crashes.

  • Empty loads, rigid vehicles, night driving and time on task associated with heavy vehicle crashes.

  • Training, minimising night driving and enforcing regular breaks could improve heavy vehicle safety.

Abstract

Objective

To determine the association between a heavy vehicle driver's work environment, including fatigue-related characteristics, and the risk of a crash in Western Australia.

Methods

This case–control study included 100 long-haul heavy vehicle drivers who were involved in a police-reported crash in WA and 100 long-haul heavy vehicle drivers recruited from WA truck stops, who were not involved in a crash in the previous 12 months. Driver demographics and driving details, work environment, vehicle and sleep-related characteristics were obtained using an interviewer-administered questionnaire. Drivers were tested for obstructive sleep apnoea using an overnight diagnostic device. Conditional multiple logistic regression analysis was undertaken to determine work environment-related factors associated with crash involvement.

Results

After accounting for potential confounders, driving a heavy vehicle with an empty load was associated with almost a three-fold increased crash risk compared to carrying general freight (adjusted OR: 2.93, 95% CI: 1.17–7.34). Driving a rigid heavy vehicle was associated with a four-fold increased risk of crashing compared to articulated heavy vehicles (adjusted OR: 4.08, 95% CI: 1.13–14.68). The risk of crashing was almost five times higher when driving more than 50% of the trip between midnight and 5.59 am (adjusted OR: 4.86, 95% CI: 1.47–16.07). Furthermore, the risk of crashing significantly increased if the time since the last break on the index trip was greater than 2 h (adjusted OR: 2.18, 95% CI: 1.14–4.17). Drivers with more than 10 years driving experience were 52% less likely to be involved in a crash (adjusted OR: 0.48, 95% CI: 0.23–0.99).

Conclusion

The results provide support for an association between a driver's work environment, fatigue-related factors, and the risk of heavy vehicle crash involvement. Greater attention needs to be paid to the creation of a safer work environment for long distance heavy vehicle drivers.

Introduction

Heavy vehicle crashes contribute significantly to the burden of death and injury on Western Australian (WA) and Australian roads. Heavy vehicle crashes result in approximately 250 deaths and 1500 hospitalisations each year in Australia (Bureau of Infrastructure Transport and Regional Economics (BITRE), 2014), with around 26 fatal and 166 serious injury crashes occurring per year in WA (Bramwell et al., 2014). The number of fatalities from crashes involving heavy vehicles declined in Australia by an average of 3.2% per year over the 10-year period between 2004 and 2013, which is similar to trends in WA (BITRE, 2014). However, 20% of all worker fatalities that have occurred in Australia during the previous decade have been truck and heavy vehicle drivers (Safe Work Australia, 2014).

Previous research indicates that the health and safety of heavy vehicle drivers is influenced by a number of factors in the work environment, including distance travelled, vehicle type, employment type, payment method, driver training, scheduling practices, working hours, and the safety climate within an organisation (Morrow and Crum, 2004, Edwards et al., 2014). However, conflicting results have been reported. For example, a large study of truck-permit holders in Quebec found that longer distances driven and a greater working radius were associated with higher crash risk (Laberge-Nadeau et al., 2000). Another study however, reported that these factors accounted for considerable variation in near miss crash involvement but not crash involvement (Morrow and Crum, 2004).

Long distance heavy vehicle driving is characterised by inherent factors that can contribute to fatigue, which is a known risk factor for heavy vehicle crashes. Hours worked, difficulty in finding rest stops, difficulty achieving continuous sleep and insufficient recovery from previous work may lead to disturbance in sleep patterns (Morrow and Crum, 2004). Specifically, fatigue has been related to scheduling issues such as night-time driving, inability to choose break times, delivery window size, more arduous schedules and higher work/time-off ratios (Edwards et al., 2014).

Limited information exists however, on heavy vehicle crashes in WA specifically. In 2008, new Heavy Vehicle Driver Fatigue Laws were introduced and all Australian States have adopted this reform except WA and the Australian Capital Territory. The laws set work and rest limits and specify records that must be kept. WA has as unique road environment with vast distances between locations and rest stops, expanses of unpopulated roadway, extreme temperatures and weather conditions and monotonous scenery. While these circumstances may increase the risk of fatigue for heavy vehicle drivers, they also limit the opportunity for frequent rest stops or trips of shorter duration. Due to this, WA has its own fatigue management regulations which are run under occupational health and safety law. These regulations allow longer working hours of up to 17 h per day and 168 h per fortnight.

A recent study on the epidemiology of police-reported articulated heavy vehicle crashes between 2001 and 2013 in WA, reported that 65% were multi-vehicle crashes, 82% occurred during daylight hours (6 am–6 pm), nearly 80% of drivers were aged 30–59 years and speed was recorded as a factor in 11% of crashes (Zhang et al., 2014). An earlier survey of WA heavy vehicle drivers on hours of work and perceptions of fatigue reported that 38% of heavy vehicle drivers exceeded 14 h of driving in a 24 h period, 20% had less than 6 h of sleep before their current journey, 14% reported nodding off at least occasionally whilst driving and 16% reported having near misses at least occasionally (Arnold et al., 1997). Of the 5% of drivers who reported crashing in the previous 9 months, 12% thought it was related to fatigue (Arnold et al., 1997). While these findings suggest fatigue may be a significant safety issue for heavy vehicle drivers, no current information exists on work environment-related risk factors for heavy vehicle crashes in WA.

Recently, a large case–control study of long distance heavy vehicle drivers was conducted in two States of Australia, New South Wales and Western Australia (Stevenson et al., 2010). The combined results of this study found that driving at night, with empty loads, less experienced drivers, lack of regular breaks and lack of vehicle safety devices increased the risk of heavy vehicle crashes in NSW and WA (Stevenson et al., 2014). However, due to WA's unique circumstances, it is important that work environment-related risk factors are examined specifically for WA portion of this study. Therefore, the aim of this study was to examine the association between work environment-related factors and the likelihood of heavy vehicle crash involvement in WA.

Section snippets

Study design and participants

This paper reports the results from the WA component of a case–control study of heavy vehicle crashes undertaken in two States of Australia (Stevenson et al., 2014). All participants were driving a heavy vehicle of ≥12 tonnes in tare weight and were undertaking a trip ≥200 km from their WA truck-base at the time of a crash (cases) or being approached for an interview (controls).

Cases consisted of 100 long distance heavy vehicle drivers who were involved in a police-reported crash in WA between

Results

The mean age of case drivers was 44.8 years (SD: 11.8) and ranged from 22 to 74 years. The control drivers had a mean age of 45.1 years (SD: 9.5) and ranged from 22 to 68 years. The majority of both case (99.0%) and control drivers (98.0%) were male. Control drivers had a mean of 18.8 (SD: 11.5) years of experience as a long distance heavy vehicle driver, whilst cases had a mean of 14.5 (SD: 12.3) years of experience. The mean take home pay of control drivers in the week before the interview

Discussion

This study identified several factors associated with long-haul heavy vehicle crashes in WA. Driving with an empty load, time since the last break (time on task), driving more than 50% of the time between midnight and 5.59 am, driving a rigid heavy vehicle, and drivers with less than ten years of experience were all significantly associated with an increased crash risk.

An increased crash risk of over four times was found when driving a rigid truck compared to an articulated truck. In contrast,

Acknowledgements

This was not an industry supported study. This work was supported by Australian Research Council Linkage grant [LP 0776308] and Main Roads Western Australia. This study was performed through the Curtin-Monash Accident Research Centre, Curtin University, Western Australia and the University of Melbourne, Victoria, Australia.

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