Rena Friswell

The impact of work practices on fatigue in long distance truck drivers.

Twenty seven professional truck drivers completed a 12 hour, 900 km trip under each of three driving regimes-a relay (staged) trip, a working hours regulated one-way (single) trip, and a one-way (flexible) trip with no working hours constraints. The results indicated that none of the driving regimes prevented fatigue and that the pattern of fatigue experienced during the trips appeared to be related to pretrip fatigue levels.

Developing measures of fatigue using an alcohol comparison to validate the effects of fatigue on performance

The effects of 28 h of sleep deprivation were compared with varying doses of alcohol up to 0.1% blood alcohol concentration (BAC) in the same subjects. The study was conducted in the laboratory. Twenty long-haul truck drivers and 19 people not employed as professional drivers acted as subjects. Tests were selected that were likely to be affected by fatigue, including simple reaction time, unstable tracking, dual task, Mackworth clock vigilance test, symbol digit coding, visual search, sequential spatial memory and logical reasoning. While performance effects were seen due to alcohol for all tests, sleep deprivation affected performance on most tests, but had no effect on performance on the visual search and logical reasoning tests. Some tests showed evidence of a circadian rhythm effect on performance, in particular, simple reaction time, dual task, Mackworth clock vigilance, and symbol digit coding, but only for response speed and not response accuracy. Drivers were slower but more accurate than controls on the symbol digit test, suggesting that they took a more conservative approach to performance of this test. This study demonstrated which tests are most sensitive to sleep deprivation and fatigue. The study therefore has established a set of tests that can be used in evaluations of fatigue and fatigue countermeasures.

Characteristics of fatal motorcycle crashes into roadside safety barriers in Australia and New Zealand.

This paper reports on the findings of a retrospective case series study of fatal motorcyclist-roadside barrier collisions. Cases were retrieved from the National Coroners Information System (NCIS), the coronial case files of Australian jurisdictions, and the Crash Analysis System (CAS) of the New Zealand Transport Agency. Seventy seven (77) motorcycle fatalities involving a roadside barrier in Australia and New Zealand were examined. The fatalities usually involved a single vehicle crash and young men. The roadside barriers predominantly involved were steel W-beams, typically on a bend in the horizontal alignment of the road. A majority of fatalities occurred on a weekend, during daylight hours, on clear days with dry road surface conditions indicating predominantly recreational riding. Speeding and driving with a blood alcohol level higher than the legal limit contributed to a significant number of these fatalities.

Balancing work and rest to combat driver fatigue: An investigation of two-up driving in Australia

This study is the fourth in a series examining driver fatigue in the Australian long distance road transport industry. Thirty-seven long haul truck drivers were measured on a routine 4500 km round trip. Two types of driving operations were compared, single driving, involving a solo driver, and two-up driving, where a pair of drivers operate a truck continuously and alternate between work and rest. Two-up drivers reported higher levels of fatigue than single drivers overall and tended to show poorer levels of performance. However, this result appeared to reflect differential fatigue at the start of the trip. Both two-up and single drivers showed marked increases in fatigue across the first half of the trip, followed by a substantial recovery of alertness and performance provided that drivers had stationary overnight rest at mid trip or had shorter trips. Fatigue continued to increase on the second half of the trip for drivers who did longer trips without the benefit of a substantial night rest or who did not have access to on-board rest, that is single drivers. The use of overnight rest, in combination with two-up driving, appeared to be the most successful strategy for managing fatigue across the trip.

Exploratory study of fatigue in light and short haul transport drivers in NSW, Australia

This exploratory study sought to identify relationships between work characteristics and fatigue experiences among light and short haul road transport drivers. Surveys were distributed to drivers of light goods vehicles (< or =12 t gross vehicle mass) undertaking short haul work (within a 100 km radius of base) in seven geographical regions of NSW, Australia. The participating drivers (n=321) reported a range of freight tasks. They typically worked a 50-h, 5-day week primarily as day shifts, and spent just over half of their work time driving. Despite the predominance of regular, day work, 38% of participants experienced fatigue at least once a week while driving for work and 45% had nodded off while driving during the preceding 12 months. Stepwise logistic regression analysis revealed that longer daily work hours, higher subjective work demands, as measured by the NASA TLX workload scale, and the percentage of freight movements undertaken from customers to depots each explained unique variance in the frequency of fatigue experiences. The results of the study suggest that fatigue is an issue for some light and short haul road transport drivers and identifies work characteristics that should be investigated further.

Fatigue in the workplace: causes and countermeasures

Many workers are exposed to fatigue risk that they would rarely encounter outside their job. This paper discusses the current state of occupational fatigue research, providing a snapshot of the evidence on its causes and an overview of occupational health and safety approaches to its management. Frameworks for managing other hazards and risk in workplaces are applicable to occupational fatigue and have spurred the development of new regulatory approaches for fatigue. Although our understanding of the causes of occupational fatigue is improving, there is as yet little research evaluating fatigue risk management systems and countermeasures.

Are drivers aware of sleepiness and increasing crash risk while driving

Drivers are advised to take breaks when they feel too tired to drive, but there is question over whether they are able to detect increasing fatigue and sleepiness sufficiently to decide when to take a break. The aim of this study was to investigate the extent to which drivers have access to cognitive information about their current state of sleepiness, likelihood of falling asleep, and the implications for driving performance and the likelihood of crashing. Ninety drivers were recruited to do a 2h drive in a driving simulator. They were divided into three groups: one made ratings of their sleepiness, likelihood of falling asleep and likelihood of crashing over the next few minutes at prompts occurring at 200s intervals throughout the drive, the second rated sleepiness and likelihood of falling asleep at prompts but pressed a button on the steering wheel at any time if they felt they were near to crashing and the third made no ratings and only used a button-press if they felt a crash was likely. Fatigue and sleepiness was encouraged by monotonous driving conditions, an imposed shorter than usual sleep on the night before and by afternoon testing. Drivers who reported that they were possibly, likely or very likely to fall asleep in the next few minutes, were more than four times more likely to crash subsequently. Those who rated themselves as sleepy or likely to fall asleep had a more than 9-fold increase in the hazards of a centerline crossing compared to those who rated themselves as alert. The research shows clearly that drivers can detect changes in their levels of sleepiness sufficiently to make a safe decision to stop driving due to sleepiness. Therefore, road safety policy needs to move from reminding drivers of the signs of sleepiness and focus on encouraging drivers to respond to obvious indicators of fatigue and sleepiness and consequent increased crash risk.

Hypnotically induced mood

Abstract This article addresses theoretical and methodological issues that are central to an understanding of hypnotically induced mood. Initially, the hypnotic procedures that are typically used to induce moods are examined. Then the empirical research that has employed hypnotic moods is reviewed; specifically, the impact of hypnotic moods on physiological responses, behavioural performance, perceptual and cognitive responses, and personality, and clinical processes is examined. Finally, major theoretical and methodological issues are highlighted, and the research directions that will lead to a greater understanding of hypnotic mood are specified.

Investigating the relative effects of sleep deprivation and time of day on fatigue and performance

Time of day and the time since last sleep are acknowledged causes of fatigue, but comparatively little is known about how they interact. This study examines the relative effects of time of day and sleep deprivation on fatigue and performance. Two independent groups were exposed to 28 h of sleep deprivation beginning at 06:00 h for one group (n = 39) and at 00:00 h for the other (n = 22). By varying the start time for the two groups, but keeping constant the duration of sleep deprivation, the effects of variations in the time of day of testing could be examined. For the 06:00 h start group the longest period without sleep occurred close to the low point of the circadian rhythm. For the 00:00 h start group the circadian low point coincided with only two to six hours of sleep deprivation. Performance was evaluated two-hourly using eight computer-based tests and subjective fatigue ratings. The results showed a clear interaction effect. Both time of day and sleep deprivation affected performance but only in combination; neither had independent effects. These findings have implications for fatigue management.

Initial development of a practical safety audit tool to assess fleet safety management practices

Work-related vehicle crashes are a common cause of occupational injury. Yet, there are few studies that investigate management practices used for light vehicle fleets (i.e. vehicles less than 4.5 tonnes). One of the impediments to obtaining and sharing information on effective fleet safety management is the lack of an evidence-based, standardised measurement tool. This article describes the initial development of an audit tool to assess fleet safety management practices in light vehicle fleets. The audit tool was developed by triangulating information from a review of the literature on fleet safety management practices and from semi-structured interviews with 15 fleet managers and 21 fleet drivers. A preliminary useability assessment was conducted with 5 organisations. The audit tool assesses the management of fleet safety against five core categories: (1) management, systems and processes; (2) monitoring and assessment; (3) employee recruitment, training and education; (4) vehicle technology, selection and maintenance; and (5) vehicle journeys. Each of these core categories has between 1 and 3 sub-categories. Organisations are rated at one of 4 levels on each sub-category. The fleet safety management audit tool is designed to identify the extent to which fleet safety is managed in an organisation against best practice. It is intended that the audit tool be used to conduct audits within an organisation to provide an indicator of progress in managing fleet safety and to consistently benchmark performance against other organisations. Application of the tool by fleet safety researchers is now needed to inform its further development and refinement and to permit psychometric evaluation.