fatigue and performance in heavy truck drivers working day shift

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    December 2004

    Prepared by

    Ann Williamson (IRMRC), Rena Friswell (IRMRC), Anne-Marie Feyer (PwC)

  • National Transport Commission Fatigue and Performance in Heavy Truck Drivers Working Day Shift, Night Shift or Rotating Shifts

    Report Prepared by: Ann Williamson (IRMRC), Rena Friswell (IRMRC), Anne-Marie Feyer (Pwc) ISBN: 1 877093 77 7


    Date: December 2004

    ISBN: 1 877093 77 7

    Title: Fatigue and Performance in Heavy Truck Drivers Working Day Shift, Night Shift or Rotating Shifts

    Address: National Transport Commission Level 15/628 Bourke Street MELBOURNE VIC 3000

    E-mail: ntc@ntc.gov.au Website: www.ntc.gov.au

    Type of report: Research Report

    Objectives: This project was designed to:

    1) directly compare the impact of day and night driving on the fatigue and performance of heavy vehicle drivers under real working conditions; and

    2) determine whether levels of fatigue engendered by regular night driving pose a threat to road and occupational safety

    Abstract: Research on shiftwork has shown that fatigue and related performance problems increase at night. In Australia, this has lead to calls to limit night work for long distance heavy vehicle drivers. However the evidence for diminished performance at night among heavy vehicle drivers is equivocal, and the risks posed need to be weighed against different safety risks inherent in daytime driving. This study sought to directly compare the impact of day and night shift rosters on the fatigue and performance of heavy vehicle drivers going about their normal work. Self-reported fatigue increased similarly over the week for all drivers, but more over individual night shifts than individual day shifts. There were also indications of slowing response speed over the week but this effect was not different for night and day drivers. In short, night shifts made drivers feel more tired than day shifts, but did not produce significantly poorer performance, suggesting that night drivers can manage their fatigue. Whether these results would also apply to drivers working the types of irregular shifts common in the long-haul road transport industry requires further investigation.

    Purpose: For information

    Key words: fatigue, driving, performance, long distance road transport, trucking


    The National Transport Commissions role is to lead transport regulatory reform nationally to meet the needs of transport users and the broader Australian community for safe efficient and sustainable land transport.

    Improving the safety of Australian transport operations is a key objective and is clearly highlighted in this report. The Commission has recognized the importance of fatigue as a direct or indirect cause of crashes in the long distance road transport industry. It has undertaken a significant research and policy program in recent years to better understand the role of fatigue in these crashes and to develop well based regulatory arrangements that will reduce fatigue levels in heavy vehicle drivers.

    This project was designed to provide important insights into the relative fatigue levels of drivers who operate day shifts and those who drive at night and into the ways in which drivers manage their sleep arrangements .to minimize the impacts of fatigue.

    The project was undertaken by Dr Ann Williamson and Ms Rena Friswell of the Independent Risk Management Research Center of the University of New South Wales in conjunction with Associate Professor Anne-Marie Feyer of Price Waterhouse Coopers. The project relied on getting information from drivers as the went about their business rested and performed their family and social responsibiities. This in itself proved a challenge for the project team and demonstrated the diversity of operations in the heavy vehicle transport industry and the difficulties of matching the working arrangements of drivers who perform their tasks at different times of the day.

    The report provides interesting insights into the similarities and differences in the ways fatigue impacts on drivers who perform day, night or rotating day and night shifts. It will also assist in designing future on-road studies which aim to obtain information direct from the workers themselves. More importantly, the findings of this report will feed into the Commissions overall current and future knowledge of how fatigue affects the driving performance of long distance heavy vehicle drivers.

    The Commission wishes to thank all who participated.


    This study was undertaken with financial support from the National Road Transport Commission (NRTC), the Australian Transport Safety Bureau (ATSB), the NSW Roads and Traffic Authority (RTA) and the New Zealand Land Transport Safety Authority (LTSA NZ).

    The study would not have been possible without the support of the participating transport companies and the individual drivers who kindly took part.

    We would like to thank Professor Philippa Gander for providing the PVTs used in the study and for advice on their use.

    We were fortunate to have some very dedicated and capable people assisting with data collection. Helen Gardiner and Kristin Rogers managed data collection with drivers working out of Melbourne. Peter Hardy, Emma Grove, Therese Ma and Alex Symonds played a similar role in Sydney. Emma, Therese and Alex also made an invaluable contribution to the production of this report.

    We would also like to thank Hugh McMaster at the NSW Road Transport Association for his help in finding companies employing suitable shift rosters.


    This study took up the issue of whether there is a differential effect of night work on fatigue experiences and effects in long distance road transport driving compared to day work. The study involved on-road evaluation of 22 drivers doing permanent day shifts and 21 drivers doing permanent night shifts. This allowed comparison between drivers of levels of subjective ratings of fatigue and its effects on performance. In addition, a group of 11 drivers who were doing weekly rotating day and night shifts were also included in the study allowing examination of the effects of night and day driving in the same people. Each permanent shift driver and each rotating shift driver under each type of shift was followed for two full weeks while doing their normal work-rest schedules. The evaluation involved questionnaires asking about work and rest activities leading up to the start of the study period, demographic characteristics and details of consumption of social drugs and sleep characteristics. Drivers kept a diary of work-rest activities during the study weeks and to make ratings of their subjective fatigue and quality of last sleep at the beginning and end of each period of work separated by breaks of at least 15 minutes. Objective measures of timing and quality of sleep were taken using actigraphs worn for the two week study time. Drivers completed tests of concentration and reaction speed at the start of the study period, and at the end of the last work shift in the first and second week of the study. Drivers also self-administered shorter versions of the tests at the start and end of each work shift and at the start of one mid-shift break in each shift.

    The results showed increasing fatigue ratings across the work week which were clearly more pronounced for night shift in both permanent shift and rotating shift drivers. There was also evidence of performance decrements, especially slowing of response speed, between the beginning and end of the work week, but this was shown for all drivers. Night driving did not have any clear differential effects on performance compared to day driving in either permanent or rotating shift drivers.

    The results suggest that in practice, night driving may not be as different from day driving as previous research might suggest. This might be at least partly due to the fact that all drivers in this study did similar long hours of work and reported roughly equal degrees of fatigue across the work weeks. There were some differences between night and day drivers in this study, but these differences were also likely to have the effect of balancing the effect of night work with effective sleep. While drivers on night shifts did more driving work and permanent night drivers did longer trips compared to day drivers, night drivers used their rest differently. Night drivers apparently balanced the greater demands of night work by taking their rests earlier in the break period and taking longer rests and incorporating more naps into their days off when there was time to do so. Rotating shift drivers on day shift who needed to adapt to very early morning starts showed a similar response.

    In conclusion, the study indicates that consecutive night driving shifts in a regular work-rest schedule clearly make drivers feel more tired than day driving shifts, but they do not necessarily produce significantly poorer or unacceptable levels of performance decrement in professional drivers who are accustomed to night work. It may be misleading, however, to extend these results to other work-rest schedules, especially where the schedule is irregular, or where work, break and sleep times differ from those undertaken by the drivers in this study.

    The full report of this research can be found at www.ntc.gov.au


    1. INTRODUCTION ............................................................................................................. 1



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