Seafarer sleepiness jeopardizes safety at sea and has been documented as a direct or contributing factor in many maritime accidents. This study investigates sleep, sleepiness, and neurobehavioral performance in a simulated 4 h on/8 h off watch system as well as the effects of a single free watch disturbance, simulating a condition of overtime work, resulting in 16 h of work in a row and a missed sleep opportunity. Thirty bridge officers (age 30 +/- 6 yrs; 29 men) participated in bridge simulator trials on an identical 1-wk voyage in the North Sea and English Channel. The three watch teams started respectively with the 00-04, the 04-08, and the 08-12 watches. Participants rated their sleepiness every hour (Karolinska Sleepiness Scale [KSS]) and carried out a 5-min psychomotor vigilance test (PVT) test at the start and end of every watch. Polysomnography (PSG) was recorded during 6 watches in the first and the second half of the week. KSS was higher during the first (mean +/- SD: 4.0 +/- 0.2) compared with the second (3.3 +/- 0.2) watch of the day (p < 0.001). In addition, it increased with hours on watch (p < 0.001), peaking at the end of watch (4.1 +/- 0.2). The free watch disturbance increased KSS profoundly (p < 0.001): from 4.2 +/- 0.2 to 6.5 +/- 0.3. PVT reaction times were slower during the first (290 +/- 6 ms) compared with the second (280 +/- 6 ms) watch of the day (p < 0.001) as well as at the end of the watch (289 +/- 6 ms) compared with the start (281 +/- 6 ms; p = 0.001). The free watch disturbance increased reaction times (p < 0.001) from 283 +/- 5 to 306 +/- 7 ms. Similar effects were observed for PVT lapses. One third of all participants slept during at least one of the PSG watches. Sleep on watch was most abundant in the team working 00-04 and it increased following the free watch disturbance. This study reveals that-within a 4 h on/8 h off shift system-subjective and objective sleepiness peak during the night and early morning watches, coinciding with a time frame in which relatively many maritime accidents occur. In addition, we showed that overtime work strongly increases sleepiness. Finally, a striking amount of participants fell asleep while on duty.

Fatiqueat sea : a simulator study of sleepiness, sleep and neurobehavioural performance during different watch schedules

Driver distraction is a contributing factor to many crashes; therefore, a real-time distraction warning system should have the potential to mitigate or circumvent many of these crashes. The objective of this paper is to investigate the usefulness of a real-time distraction detection algorithm called AttenD. The evaluation is based on data from an extended field study comprising seven drivers who drove on an average of 4351 ± 2181 km in a naturalistic setting. Visual behavior was investigated both on a global scale and on a local scale in the surroundings of each warning. An increase in the percentage of glances at the rear-view mirror and a decrease in the amount of glances at the center console were found. The results also show that visual time sharing decreased in duration from 9.94 to 9.20 s due to the warnings, that the time from fully attentive to warning decreased from 3.20 to 3.03 s, and that the time from warning to full attentiveness decreased from 6.02 to 5.46 s. The limited number of participants does not allow any generalizable conclusions, but a trend toward improved visual behavior could be observed. This is a promising start for further improvements of the algorithm and the warning strategy.

The development of a new technology, the definition of a new regulation or an organisational change aims to increase a positive performance (i.e. safety and cost effectiveness) or decrease a negative performance (i.e. occurrence of accidents or workload) in a system. However, change can also be the origin of consequences that have not been anticipated during the design phase. Such consequences can be positive, negative or damaging for the system. Consequently, an assessment phase is often integrated into technical, regulatory or organisational design activities. This assessment phase is generally structured with hazard identification and risk assessment steps that are followed by a cost benefit analysis and formulation of recommendations. The IMPACT project aims to extend the scope of the hazard identification phase generally based on traditional failure analysis methods (i.e. FMEA, THERP) by integrating stakeholder expertise and applying resilience engineering approaches of safety management. The project has also tested the possibility to use a cluster of bridge simulators together with a system for data collection and visualization in order to explore the consequences of change in maritime settings.

The term “good seamanship” is often used to describe the behaviour of deck officers who navigate according to a commonly accepted set of norms. Even though these norms offer a certain flexibility, most of them are covered by laws and regulations. The navigation performance of deck officers is also of interest, and it could be argued that there is a connection between the terms. For training and evaluation of deck officers an objective assessment of performance is also of great advantage. The scope of the paper is to analyse how different measures can be used to describe navigation performance, and the relationship between these in different collision situations. During an extended simulator study with 50 deck officers, navigation performance was assessed while participants spent one complete week in navigation simulators. Their task was a realistic 24/7 voyage through the English Channel, and each participant spent 64 or 90 hours in the simulator.

This Deliverable provides an outline of the process involved in task 2.2 of the ITERATE project forselecting an appropriate set of hypotheses to be tested inWorkpackages 3 (Experimental design andscenario specification), and 4 (Experimental studies).During a workshop with all partners involved in the project, hypotheses were formulated for thethree main system functionalities outlined in D2.1: those that support speed management (SpeedManagement), systems that support system object detection and avoidance (Collision Avoidance)and those that monitor operator state (Operator State). In formulating these hypotheses, partnerswere encouraged to consider systematically the effect of operator state and different operatorgroups on interaction with these three systems. To allow succinct formulation of hypotheses, fouroperator based parameters which are thought to affect operator behaviour with the system, wereidentified: sensation-seeking, hazard perception, fatigue and (high and low) task demand. Informulating hypotheses, partnerswere encouraged to consider the whole process linking a cause toan effect, with a clear mechanism that would link the two.

Driving and operating a vehicle is to a great extent a visual task. In driver behaviour studies it is therefore important to be able to measure where the driver is looking. Today this can be done unobtrusively and remotely in real-time with camera based eye tracking. The most common remote eye tracking systems use multiple cameras in order to give satisfactory results. However, promising results using only one camera has recently emerged on the market. The main objective of this study is to compare eye tracking systems with one and three cameras, respectively, during various measurement conditions. A total of 53 participants were enrolled in the study. Data from the two eye trackers were acquired and analysed in terms of availability, accuracy and precision. The results indicate that both availability and accuracy are affected by many different factors. The most important factors are the number of cameras that is used and the angular distance from straight ahead. In the central region (straight ahead) both one-camera and three-camera systems have a high degree of accuracy and availability, but with increasing distance from the central region, the results deteriorate. This effect falls harder upon the one-camera system. Interestingly, there were no significant effects when wearing glasses in either availability or accuracy. There was however an interaction effect between distance and glasses. Advantages with a one-camera system are that it is cheaper, easier to operate and easier to install in a vehicle. A multi-camera system will, on the other hand, provide higher availability and accuracy for areas that are far from the road centre. A one-camera system is thus mostly suitable for in-vehicle applications such as systems that warn drivers for sleepiness or distraction while multi-camera solutions are preferable for research purposes.

BACKGROUND:Today many merchant ships sail with only two nautical officers, working a shift schedule of 6 hr on and 6 hr off. There are concerns that such a shift schedule is related to fatigue. However, little data exist from onboard studies of seafarers.METHODS:Data were collected on board 13 ships. Fifteen participants worked on a 6-on, 6-off watch system and another 15 on a 4-on, 8-off watch system. Electrooculography, actigraphy, diaries, and reaction time tests were used to measure the effects of shift system on fatigue and sleep.RESULTS AND CONCLUSIONS:Sleepiness was higher during the night shift in the 6-on, 6-off system. Moreover, sleepiness increased more during the watch in the 6-on, 6-off system compared to the 4-on, 8-off system. There was a trend toward shorter sleep episodes in the 6-on, 6-off system and sleep was more often split into two episodes.