Seat belt usage in buses – An observation study of usage and travellers’ perspectives

This study aims to evaluate seat belt usage in buses and to understand travellers’ incentives of seat belt usage. Methods used are observational studies (10 cities, with 328 bus observations), focus group discussion (7 groups with a total of 32 participants) and a web survey (n = 1737 respondents). The results show that the seat belt use among bus passengers can be improved especially in regional and commercial bus traffic. It is more common to buckle up on long trips than on short trips. However, even though observations show high usage during long trips, travellers report that they remove the seat belt after a while if they want to sleep or for comfort reasons. For the bus drivers it is not possible to control passengers’ usage. Dirty seat belts and technical malfunction might deter some passengers from using them and therefore systematic cleaning and control of seats and belts are recommended. On short trips one reason for not using the belt is related to worries about getting stuck and not being ready to get off in time. In general, it is most important to increase the usage on high-speed roads (>60 km/h), in lower speed it might be more important to provide a seat for each passenger. Based on the results a list of recommendations is presented

Detecting Driver Sleepiness Using Consumer Wearable Devices in Manual and Partial Automated Real-Road Driving

Driver sleepiness constitutes a well-known traffic safety risk. With the introduction of automated driving systems, the chance of getting sleepy and even falling asleep at wheel could increase further. Conventional sleepiness detection methods based on driving performance and behavior may not be available under automated driving. Methods based on physiological measurements such as heart rate variability (HRV) becomes a potential solution under automated driving. However, with reduced task load, HRV could potentially be affected by automated driving. Therefore, it is essential to investigate the influence of automated driving on the relation between HRV and sleepiness. Data from real-road driving experiments with 43 participants were used in this study. Each driver finished four trials with manual and partial automated driving under normal and sleep-deprived condition. Heart rate was monitored by consumer wearable chest bands. Subjective sleepiness based on Karolinska sleepiness scale was reported at five min interval as ground truth. Reduced heart rate and increased overall variability were found in association with severe sleepy episodes. A binary classifier based on the AdaBoost method was developed to classify alert and sleepy episodes. The results indicate that partial automated driving has small impact on the relationship between HRV and sleepiness. The classifier using HRV features reached area under curve (AUC) = 0.76 and it was improved to AUC = 0.88 when adding driving time and day/night information. The results show that commercial wearable heart rate monitor has the potential to become a useful tool to assess driver sleepiness under manual and partial automated driving

Detecting driver fatigue using heart rate variability: A systematic review

Driver fatigue detection systems have potential to improve road safety by preventing crashes and saving lives. Conventional driver monitoring systems based on driving performance and facial features may be challenged by the application of automated driving systems. This limitation could potentially be overcome by monitoring systems based on physiological measurements. Heart rate variability (HRV) is a physiological marker of interest for detecting driver fatigue that can be measured during real life driving. This systematic review investigates the relationship between HRV measures and driver fatigue, as well as the performance of HRV based fatigue detection systems. With the applied eligibility criteria, 18 articles were identified in this review. Inconsistent results can be found within the studies that investigated differences of HRV measures between alert and fatigued drivers. For studies that developed HRV based fatigue detection systems, the detection performance showed a large variation, where the detection accuracy ranged from 44% to 100%. The inconsistency and variation of the results can be caused by differences in several key aspects in the study designs. Progress in this field is needed to determine the relationship between HRV and different fatigue causal factors and its connection to driver performance. To be deployed, HRV-based fatigue detection systems need to be thoroughly tested in real life conditions with good coverage of relevant driving scenarios and a sufficient number of participants

Challenges in Fatigue Research and Enforcement

This chapter describes challenges faced in fatigue research and in fatigue evaluation for various purposes including crash statistics and enforcement and for selection of appropriate countermeasures. The challenges are related to both the causes and the consequences of fatigue. Differences between sleep-related and task-related fatigue are discussed in relation to countermeasures for fatigue. The chapter also describes how individual characteristics including age, chronotype, and personality influence the development of fatigue and add to the complexity of choosing appropriate fatigue countermeasures. Difficulties in measuring and providing proof that an individual is fatigued are discussed in relation to law enforcement

Salivary cortisol response to acute stress and its relation to psychological factors in women with chronic trapezius myalgia - A pilote study

This study investigated differences in HPA axis function, measured as salivary cortisol concentrations, between 18 women with chronic trapezius myalgia (MYA) and 30 healthy female controls (CON). In addition, the interactions between HPA axis reactions to psychosocial stress and aspects of pain, health and psychological symptoms were analyzed. Salivary cortisol was measured both in daily life, to assess the circadian profile, and in the laboratory during light repetitive work and standardized psychosocial stress (Trier Social Stress Test, TSST). MYA and CON exhibited similar circadian rhythms and comparable salivary cortisol response magnitudes after TSST. In subjects defined as responders to the TSST, the mean peak time point of the cortisol response after TSST differed significantly between MYA and CON. Furthermore, negative psychological states and higher pain intensity were related to a slower HPA axis response to TSST. Low circadian variations in cortisol and smaller cortisol responses to TSST were found among subjects scoring high on anxiety sensitivity. Thus, a relatively favorable sample of female chronic trapezius myalgia patients exhibited normal circadian rhythm and normal salivary cortisol response magnitudes after a psychosocial stress test. In the subgroup of responders, the MYA group showed indications of a slower salivary cortisol response to psychosocial stress. Further studies are needed to elucidate the possibility of altered HPA axis activity in terms of a slower salivary cortisol response. \ua9 2009 Elsevier Ltd

Salivary cortisol response to acute stress and its relation to psychological factors in women with chronic trapezius myalgia - A pilote study

This study investigated differences in HPA axis function, measured as salivary cortisol concentrations, between 18 women with chronic trapezius myalgia (MYA) and 30 healthy female controls (CON). In addition, the interactions between HPA axis reactions to psychosocial stress and aspects of pain, health and psychological symptoms were analyzed. Salivary cortisol was measured both in daily life, to assess the circadian profile, and in the laboratory during light repetitive work and standardized psychosocial stress (Trier Social Stress Test, TSST). MYA and CON exhibited similar circadian rhythms and comparable salivary cortisol response magnitudes after TSST. In subjects defined as responders to the TSST, the mean peak time point of the cortisol response after TSST differed significantly between MYA and CON. Furthermore, negative psychological states and higher pain intensity were related to a slower HPA axis response to TSST. Low circadian variations in cortisol and smaller cortisol responses to TSST were found among subjects scoring high on anxiety sensitivity. Thus, a relatively favorable sample of female chronic trapezius myalgia patients exhibited normal circadian rhythm and normal salivary cortisol response magnitudes after a psychosocial stress test. In the subgroup of responders, the MYA group showed indications of a slower salivary cortisol response to psychosocial stress. Further studies are needed to elucidate the possibility of altered HPA axis activity in terms of a slower salivary cortisol response. \ua9 2009 Elsevier Ltd