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

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 5.59am (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 2h (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.