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Road Traffic Injury

1. Study of fatigue in motorcycle day rides

Centre Investigators
Ann Williamson, Rena Friswell, Therese Ma

Summary
Twenty volunteer motrocyclists recruited through the Motorcycle Council of NSW undertook a supervised 274km ride from Sydney to the town of Roberston and back. The trip averaged approximately 6 hrous and included 3 mandatory breaks totalling 1:10. Before and after the trip, measures of subjective fatigue, reaction speed and sustained attention were taken, and riders assessed their fatigue at intervals throughout the trip. At the end of the day, the perceived workload of the day's activities was assessed as was physical fatigue. On a second Control day, a week before or after the ride, participants provided the same measures at equivalent times of day as on the ride day, but spent the day engaged in sedentary activities. Background questionnaires confirmed that lifestyle factors with the potential to affect fatigue on the study days (e.g. sleep patterns) were similar prior to the ride and the Control days. The days differed in terms of perceived workload, with the ride day entailing higher workload, particularly in terms of mental demand, physical demand and effort. Riders also reported higher levels of physical fatigue after the ride.
During the latter part of the ride, subjective fatigue appeared to be increasing, but was not statistically different from levels at the end of the Control day. Similarly, there was some evidence that the stability of reaction speed was more affected by the ride than Control day activities. The results appear to reflect the early stages of fatigue development, but replication on a longer ride would be need to confirm this. The results do suggest that, in rested riders, a day ride of approximately 4.75 hours broken by spaced brakes of 1 hour 10 minutes, does not compromise safe performance more than a day of sedentary activity.


2. Fatigue management programmes: Impact on sleep, fatigue and performance

Centre Investigators
Ann Williamson, Samantha Sadural, Rena Friswell

Collaborator
Anne-Marie Feyer (PricewaterhouseCoopers/NEOH, University of Otago)

Summary
A project to evaluate non-regulatory, alternatives approaches to work-rest scheduling for long distance road transport drivers. Two groups of drivers working in different sections of the company were studied. The first group (long distance drivers) was measured across a normal working week under regulated working hours and then, 6 months later, under their company's fatigue management plan (FMP). Drivers reaction time and sustained attention were tested at the start and end of the week, and they were asked to self-administer tests at the start and end of each break containing sleep during the week. Drivers also completed a diary, reporting on their subjective fatigue, work, and sleep, and wore ambulatory motion monitors for the duration of their participation. The second group of drivers carried sugar cane from local farms to the cane mills, with many short round-trips made per shift. This work occured around the clock, so that the drivers worked rotating rosters. The impact of variations among and within rosters was examined. Drivers participated for a complete cycle of their roster. Like the long distance drivers, cane drivers were asked to complete reaction speed and attention tasks at the start and end of each work shift, to complete diary records of their work, sleep, and subjective fatigue, and to wear a motion monitor. The major modification introduced by the FMP for long distance drivers allowed the splitting of the mandatory six hour daily rest period into two shorter breaks totalling eight hours. Results showed little impact of FMP introduction on rest-taking practices but working hours increased slightly. Subjective fatigue increased and perforamnce deteriorated over the work week before and after FMP introduction, however there was some evidence that longer working hours under the FMP were associated with lightly poorer performance. The results for cane drivers showed clear adverse effects of night work compared to day work. Subjective fatigue and performance deteriorated across 8 and 12 hours night shifts and 8 hours afternoon shifts, but improved over day shifts. Shift length had little impact on fatigue and performance in these rosters.


3. Evaluating differences in heavy vehicle driver fatigue levels for day and night driving

Centre Investigators
Ann Williamson, Rena Friswell

Collaborators
Anne-Marie Feyer (PricewaterhouseCoopers/NEOH, University of Otago), Phiippa Gander (Sleep/Wake Research Centre, University of Otago)

Summary
Truck drivers working continuous day shifts, continuous night shifts or rotating day and night shifts were recruited from a number of transport companies operating out of Sydney and Melbourne. The drivers participated in the study for a two week period. During this time they were tested for reaction speed and sustained attention at the start of their first week and at the end of the first and second weeks of participation. They were also asked to self administer these tests and record their work hours, and subjective fatigue at the start and end of each shift and in the middle of each shift during the two weeks of participation. Drivers wore an ambulatory motion monitor for the duration of the study to provide objective information about their sleep, to be used in conjunction with self-reports of sleep. Both subjective fatigue and performance deteriorated across the working week, but only subjective fatigue showed greater effects of night shift than day shift, and did so regardless of whether the night work was on a permanent or rotating basis.

The study indicates that consecutive night driving shift in a regular work-rest schedule clearly make drivers more tired than day driving shifts, but they do not produce significantly poorer or unacceptable levels of performance decrement. 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 experienced by the drivers in this study.


4. Analysis of heavy truck crashes in NSW 1996-2000

Centre Investigators
Ann Williamson, Penny Irvine, Rena Friswell

Summary
This analysis used the RTA’s Traffic Accident Database System (TADS) to produce a description of the character of heavy truck crashes in NSW. For this analysis, heavy trucks were defined as having a tare weight greater than 4.5 tonnes. Analysis included rigid, articulated, Bdoubles/roadtrains. The analysis showed that heavy trucks had higher crash rates than seen for all crashes when expressed as rates per registered vehicle, but rates per kilometre travelled which is probably a better measure of road exposure did not show great differences between heavy truck crashes and all crashes. Fatal crashes rates per registered heavy trucks were around five times higher than the fatal crash rates for all registered vehicles and injury and on casualty crash rates for registered heavy trucks were two to three times higher than those for all vehicles. On the other hand crash rates per million kilometres travelled were slightly higher only for fatal heavy truck crashes compared to fatal all vehicle crashes, and injury and non casualty crashes per kilometres travelled were similar between heavy truck and all vehicle crashes. The analysis also looked in depth at the characteristics of heavy truck crashes including the timing, involvement of behavioural and other casual factors as well as the specific causes of single-vehicle heavy truck crashes and the characteristics of speeding crashes involving heavy vehicles.


5. Coronial study of fatalities from road traffic accidents which identified driver fatigue as a factor

Centre Investigators
Ann Williamson, Jane Weaver

Summary
The study examined Coronial reports of crashes that had been identified as fatigue-related based on the indirect criteria currently employed by the NSW Road and Traffic Authority and by a number of other road safety organisations around Australia . A set of 116 road crash fatalities occurring in NSW in 2000 which had been identified by the RTA as involving fatigue were investigated. All cases were read and coded by two coders to ensure accuracy of coding. Information was collected on the type of information available about the involvement of fatigue. This included whether information was available on the time of day, time since waking, reported fatigue in the period leading up to the crash, the amount of sleep in the period leading to the crash and recent work-rest period. Cases were coded according to the degree of evidence that fatigue was involved. Analysis of the characteristics of these crashes showed that the criteria used to define fatigue-related crashes is only partly successful. A significant proportion of crashes judged to be fatigue-related on current RTA criteria did not actually involve fatigue. Just less than two-third of cases (64.1%) were found, on investigation, to involve fatigue. Around one-quarter of cases were judged to definitely not involve fatigue and for a small minority there was too little information to make a judgement. Cases that were judged to not involve fatigue involved medical factors, other drugs or alcohol. In many cases some of the critical information needed to make judgements about fatigue-relatedness were not available in the Coroners record. Around 60 percent of these cases were judged as certainly or probably involving fatigue, but more than one-third of cased were judged as only possible involving fatigue. Analysis of the types of information used to distinguish fatigue-relatedness showed that most cases were judged as involving fatigue due to the nature of the crash, but the same characteristics of the crash occurred in the non-fatigue related crashes. The fatigue-related crashes were, however, distinguished by other fatigue-related factors particularly the time of day and time since waking, but also reported fatigue in the period leading to the crash, the length of the last sleep period and the hours worked. This suggests that these factors will distinguish fatigue-related crashes, but that this information is not collected for all cases. To improve the detection of fatigue-related crashes efforts should be made to collect this information for all fatal road traffic crashes. This analysis has demonstrated that the criteria for fatigue-related crashes need to be revisited. The result suggests that the information collected about the circumstances of crashes needs to be broadened.


6. Evaluation of the likely impact of proposed changes to the working hours regulations governing long distance truck drivers: Evidence from drivers' self-reports of work-rest experiences

Centre Investigators
Ann Williamson, Rena Friswell

Collaborator
Anne-Marie Feyer (PricewaterhouseCoopers/NEOH, University of Otago)

Summary
In 1998, a national survey of long distance truck drivers was conducted for the National Road Transport Commission and Australian Transport Safety Bureau. In this survey, drivers were asked to report their working hours for the previous week. These data were re-examined to determine what percentage of drivers and drivers’ shifts would not meet the proposed new regulations with regard to the length of daily rest breaks, the number of consecutive overnight sleep breaks, the number of night shifts worked in a row and the work hours in shifts ending at night. The data suggested that many of the proposed changes would impact only a very small percentage of drivers or driver shifts. However, changing the length of daily breaks and limiting the length of shifts ending at night might impact a sizeable minority of drivers.

31.05.2007-->

 

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