Naturalistic field study of the restart break in US commercial motor vehicle drivers: Truck driving,sleep, and fatigue

Commercial motor vehicle (CMV) drivers in the US may start a new duty cycle after taking a 34-h restart break. A restart break provides an opportunity for sleep recuperation to help prevent the build-up of fatigue across duty cycles. However, the effectiveness of a restart break may depend on its timing, and on how many nighttime opportunities for sleep it contains. For daytime drivers, a 34-h restart break automatically includes two nighttime periods. For nighttime drivers, who are arguably at increased risk of fatigue, a 34-h restart break contains only one nighttime period. To what extent this is relevant for fatigue depends in part on whether nighttime drivers revert back to a nighttime-oriented sleep schedule during the restart break. We conducted a naturalistic field study with 106 CMV drivers working their normal schedules and performing their normal duties. These drivers were studied during two duty cycles and during the intervening restart break. They provided a total of 1260 days of data and drove a total of 414,937 miles during the study. Their duty logs were used to identify the periods when they were on duty and when they were driving and to determine their duty cycles and restart breaks. Sleep/wake patterns were measured continuously by means of wrist actigraphy. Fatigue was assessed three times per day by means of a brief psychomotor vigilance test (PVT-B) and a subjective sleepiness scale. Data from a truck-based lane tracking and data acquisition system were used to compute lane deviation (variability in lateral lane position). Statistical analyses focused on 24-h patterns of duty, driving, sleep, PVT-B performance, subjective sleepiness, and lane deviation. Duty cycles preceded by a restart break containing only one nighttime period (defined as 01:00–05:00) were compared with duty cycles preceded by a restart break containing more than one nighttime period. During duty cycles preceded by a restart break with only one nighttime period, drivers showed more nighttime-oriented duty and driving patterns and more daytime-oriented sleep patterns than during duty cycles preceded by a restart break with more than one nighttime period. During duty cycles preceded by a restart break with only one nighttime period, drivers also experienced more lapses of attention on the PVT-B and increased lane deviation at night, and they reported greater subjective sleepiness. Importantly, drivers exhibited a predominantly nighttime-oriented sleep schedule during the restart break, regardless of whether the restart break contained only one or more than one nighttime period. Consistent with findings in laboratory-based studies of the restart break, the results of this naturalistic field study indicate that having at least two nighttime periods in the restart break provides greater opportunity for sleep recuperation and helps to mitigate fatigue.     

Sleepiness,sleep, and use of sleepiness countermeasures in shift-working long-haul truck drivers

Driver sleepiness is a prevalent phenomenon among professional drivers working unconventional and irregular hours. For compromising occupational and traffic safety, sleepiness has become one of the major conundrums of road transportation. To further elucidate the phenomenon, an on-road study canvassing the under-explored relationship between working hours and sleepiness, sleep, and use of sleepiness countermeasures during and outside statutory rest breaks was conducted. Testing the association between the outcomes and working hours, generalized estimating equations models were fitted on a data collected from 54 long-haul truck drivers (mean 38.1 ± 10.5 years, one female) volunteering in the 2-week study. Unobtrusive data-collection methods applied under naturalistic working and shift conditions included the Karolinska Sleepiness Scale (KSS) measuring sleepiness, a combination of actigraphy and sleep-log measuring sleep, and self-report questionnaire items incorporated into the sleep-log measuring the use of sleepiness countermeasures during and outside statutory rest breaks. Drivers’ working hours were categorized into first and consecutive night, morning and day/evening shifts based on shift timing. The results reveal severe sleepiness (KSS ≥ 7) was most prevalent on the first night (37.8%) and least on the morning (10.0%) shifts. Drivers slept reasonably well prior to duty hours, with main sleep being longest prior to the first night (total sleep time 7:21) and shortest prior to the morning (total sleep time 5:43) shifts. The proportion of shifts whereby drivers reported using at least one sleepiness countermeasure outside statutory rest breaks was approximately 22% units greater for the night than the non-night shifts. Compared to the day/evening shifts, the odds of severe sleepiness were greater only on the first night shifts (OR 6.4–9.1 with 95% confidence intervals, depending on the statistical model), the odds of insufficient daily sleep were higher especially prior to the consecutive night shifts (OR 3.5 with 95% confidence intervals), and the odds of using efficient sleepiness countermeasures outside statutory rest breaks were greater on the first as well as consecutive night shifts (OR 4.0–4.6 with 95% confidence intervals). No statistically significant association was found between shift type and use of efficient sleepiness countermeasures during statutory rest breaks. In all, the findings demonstrate marked differences in the occurrence of severe sleepiness at the wheel, sleep preceding duty hours, and the use of sleepiness countermeasures between different shift types. In addition, although drivers slept reasonably well in connection with different shift types, the findings imply there is still room for improvement in alertness management among this group of employees.     

Associations among nocturnal sleep,daytime intradialytic sleep,and mortality risk in patients on daytime conventional hemodialysis: US Renal Data System special study data

Fragmented nocturnal sleep is commonly reported by patients undergoing daytime conventional hemodialysis (CHD) and may be associated with higher mortality risk. Subjective sleepiness during CHD is also frequently observed. We examined the association of reported sleep fragmentation and nocturnal and daytime (intradialytic) sleep durations with survival in a national cohort of 1440 CHD patients who were interviewed in 2005–2007 in a phone survey conducted by the US Renal Data System. Patient survival was followed through September 30, 2010 in the US Renal Data System. A total of 76% of patients reported that they typically dozed off or slept during their treatment, and intradialytic dozing was especially common among patients whose treatment shift started before 1000 hours. There was a trend for patients who reported dozing during CHD to report nocturnal sleep fragmentation (60.4% vs. 55.1%; P = 0.07). With adjustment for intradialytic sleep and other covariates, nocturnal sleep fragmentation was not associated with survival. Mortality risk was higher for patients who reported sleeping 9 or more hours/night compared with the referent category of nocturnal sleep equal to 6–7 hours (hazard ratio: 1.50 [95% confidence interval: 1.04–2.17]; P = 0.03). Continued investigation of the association of timing and duration of sleep with hemodialysis patient outcomes is warranted.     

An explorative study of the relationship between lifestyle and driving behaviour among young drivers

The high accident risk among young drivers is a well-known and well-documented fact in most countries, including Denmark. Lifestyle has proven to be related to driving behaviour as well as accident risk among young drivers. However, the underlying process through which the relationship between the lifestyle and the driving behaviour is established is not yet fully understood. Using focus group interviews divided by sex and education this study explores the psychosocial function of driving as well as the process through which a relationship between lifestyle and driving behaviour is established. Twenty-nine young drivers living in the Copenhagen area participated in the study. Data were analysed using a modified version of the Editing Analysis Style.     

Unlicensed driving and other related health risk behaviors: A study of Montana high school students

Purpose

Health risk behaviors tend to cluster in young people, not least among young drivers. Less is known about the health risk profile of young unlicensed drivers. This study investigates health risk behaviors among young unlicensed drivers compared to both their licensed and driving peers, and their non-driving peers.

Methods

High school students participating in the Youth Risk Behavior Surveillance System in Montana (US) and age-eligible to have a driver's license were studied (n = 5985), categorized according to their self-reported car driving and license practice (licensed driving, unlicensed driving, and non-driving). Ten health risk behaviors, of which four were related to car riding/driving, were considered. Multinomial logistic regression was used to compile sex-specific odds ratios (with 95% confidence intervals) of adopting those behaviors using licensed drivers as a reference and adjusting for age and race/ethnicity.

Results

Health risk behaviors tended to be more common among unlicensed drivers than other groups, although some behaviors were prevalent in all groups (i.e., alcohol use and lack of seat belt use). As a consequence, for both male and female students, there was a significant association between unlicensed driving and most health risk behaviors, except for being involved in a physical fight and riding with a drinking driver among female students.

Conclusions

Young unlicensed drivers are more likely than licensed drivers to adopt several health risk behaviors both in car driving/riding or otherwise, in particular alcohol use and cigarette smoking. This challenges any simplistic approach as unlicensed driving in youth is not an isolated act suggesting public health and traffic safety initiatives.     

The impact of young drivers’ lifestyle on their road traffic accident risk in greater Athens area

Young drivers (18–24) both in Greece and elsewhere appear to have high rates of road traffic accidents. Many factors contribute to the creation of these high road traffic accidents rates. It has been suggested that lifestyle is an important one. The main objective of this study is to find out and clarify the (potential) relationship between young drivers’ lifestyle and the road traffic accident risk they face. Moreover, to examine if all the youngsters have the same elevated risk on the road or not. The sample consisted of 241 young Greek drivers of both sexes. The statistical analysis included factor analysis and logistic regression analysis. Through the principal component analysis a ten factor scale was created which included the basic lifestyle traits of young Greek drivers. The logistic regression analysis showed that the young drivers whose dominant lifestyle trait is alcohol consumption or drive without destination have high accident risk, while these whose dominant lifestyle trait is culture, face low accident risk. Furthermore, young drivers who are religious in one way or another seem to have low accident risk. Finally, some preliminary observations on how health promotion should be put into practice are discussed.     

Examining signs of driver sleepiness,usage of sleepiness countermeasures and the associations with sleepy driving behaviours and individual factors

The impairing effect from sleepiness is a major contributor to road crashes. The ability of a sleepy driver to perceive their level of sleepiness is an important consideration for road safety as well as the type of sleepiness countermeasure used by drivers as some sleepiness countermeasures are more effective than others. The aims of the current study were to determine the extent that the signs of driver sleepiness were associated with sleepy driving behaviours, as well as determining which individual factors (demographic, work, driving, and sleep-related factors) were associated with using a roadside or in-vehicle sleepiness countermeasure. A sample of 1518 Australian drivers from the Australian State of New South Wales and the neighbouring Australian Capital Territory took part in the study. The participants’ experiences with the signs of sleepiness were reasonably extensive. A number of the early signs of sleepiness (e.g., yawning, frequent eye blinks) were related with continuing to drive while sleepy, with the more advanced signs of sleepiness (e.g., difficulty keeping eyes open, dreamlike state of consciousness) associated with having a sleep-related close call. The individual factors associated with using a roadside sleepiness countermeasure included age (being older), education (tertiary level), difficulties getting to sleep, not continuing to drive while sleepy, and having experienced many signs of sleepiness. The results suggest that these participants have a reasonable awareness and experience with the signs of driver sleepiness. Factors related to previous experiences with sleepiness were associated with implementing a roadside countermeasure. Nonetheless, the high proportions of drivers performing sleepy driving behaviours suggest that concerted efforts are needed with road safety campaigns regarding the dangers of driving while sleepy.     

An exploratory study of the relationship between road rage and crash experience in a representative sample of US drivers

The phenomenon of road rage has been frequently discussed but infrequently examined. Using a representative sample of 1382 US adult drivers, who were interviewed in a 1998 telephone survey, exploratory analyses examined the relationship between self-reported measures of road rage, generally hazardous driving behaviors, and crash experience. Regarding specific road rage behaviors, most respondents reported having engaged in verbal expressions of annoyance; however only 2.45% reported ever having been involved in direct confrontation with another car or driver. After controlling for gender, age. driving frequency, annual miles driven and verbal expression, an angry/threatening driving subscale of road rage was significantly associated with hazardous driving behaviors that included frequency of driving over the legal blood alcohol limit, receipt of tickets in the past year. and habitually exceeding the speed limit as well as crash experience. However, the verbal/frustration expression subscale was not associated with crash experience or hazardous driving indicators, except for number of tickets, after controlling for other crash-related factors such as gender and age. Direct confrontation by deliberately hitting another car or leaving the car to argue with and/or injure another driver was rarely reported. Results suggest that angry/threatening driving is related to crash involvement; however, after controlling for exposure and angry/threatening and hazardous driving the relationship of milder expressions of frustration while driving and crash involvement was not significant.     

Continuing to drive while sleepy: The influence of sleepiness countermeasures,motivation for driving sleepy,and risk perception

Driver sleepiness is a major contributor to road crashes. The current study sought to examine the association between perceptions of effectiveness of six sleepiness countermeasures and their relationship with self-reports of continuing to drive while sleepy among 309 drivers after controlling for the influence of age, sex, motivation for driving sleepy, and risk perception of sleepy driving. The results demonstrate that the variables of age, sex, motivation, and risk perception were significantly associated with self-reports of continuing to drive while sleepy and only one countermeasure was associated with self-reports of continuing to drive while sleepy. Further, it was found that age differences in self-reports of continuing to drive while sleepy was mediated by participants’ motivation and risk perception. These findings highlight modifiable factors that could be focused on with interventions that seek to modify drivers’ attitudes and behaviours of driving while sleepy.     

Sharing the responsibility for driver distraction across road transport systems: A systems approach to the management of distracted driving

Distracted driving is acknowledged universally as a large and growing road safety problem. Compounding the problem is that distracted driving is a complex, multifaceted issue influenced by a multitude of factors, organisations and individuals. As such, management of the problem is not straightforward. Numerous countermeasures have been developed and implemented across the globe. The vast majority of these measures have derived from the traditional reductionist, driver-centric approach to distraction and have failed to fully reflect the complex mix of actors and components that give rise to drivers becoming distracted. An alternative approach that is gaining momentum in road safety is the systems approach, which considers all components of the system and their interactions as an integrated whole. In this paper, we review the current knowledge base on driver distraction and argue that the systems approach is not currently being realised in practice. Adopting a more holistic, systems approach to distracted driving will not only improve existing knowledge and interventions from the traditional approach, but will enhance our understanding and management of distraction by considering the complex relationships and interactions of the multiple actors and the myriad sources, enablers and interventions that make up the distracted driving system. It is only by recognising and understanding how all of the system components work together to enable distraction to occur, that we can start to work on solutions to help mitigate the occurrence and consequences of distracted driving.     

Crash risk and aberrant driving behaviors among bus drivers: The role of personality and attitudes towards traffic safety

Several studies have shown that personality traits and attitudes toward traffic safety predict aberrant driving behaviors and crash involvement. However, this process has not been adequately investigated in professional drivers, such as bus drivers. The present study used a personality–attitudes model to assess whether personality traits predicted aberrant self-reported driving behaviors (driving violations, lapses, and errors) both directly and indirectly, through the effects of attitudes towards traffic safety in a large sample of bus drivers. Additionally, the relationship between aberrant self-reported driving behaviors and crash risk was also assessed.     

Preventing risky driving: A novel and efficient brief intervention focusing on acknowledgement of personal risk factors

Impulsive personality is an important predictor of risky driving. Acknowledging their impulsive tendencies may help novice drivers to drive more safely. The aim of this study was to evaluate the efficacy of a novel brief intervention targeting novice drivers’ risky behavior in traffic, taking into account potential moderator effects. Driving school students (n = 1866) were divided into an intervention group and a control group. The intervention consisted of a lecture and group work (1.5 h). Subjects’ traffic offenses and crashes were monitored during the following year using police and traffic insurance fund databases. The groups were similar in their baseline characteristics. The intervention group had half as many speeding violations in the year following the intervention compared with the controls. The proportion of speeders was significantly lower in the intervention group compared with the control group in subgroups of subjects with medium cognitive abilities and low or medium BIS-11 impulsiveness levels. In alpha_2A-adrenoceptor gene (ADRA2A) G allele carriers, general traffic risk and speeding decreased in response to the intervention, unlike in subjects with the CC genotype. It is concluded that brief interventions that are integrated into the driving education program and focus on personal psychological risk factors may be effective for improving traffic safety.     

Addressing the road trauma burden in China: Exploring attitudes,behaviours, risk perceptions and cultural uniqueness

As China continues to motorise rapidly, solutions are needed to reduce the burden of road trauma that is spread inequitably across the community. Little is currently known about how new drivers are trained to deal with on-road challenges, and little is also known about the perceptions, behaviours and attitudes of road users in China. This paper reports on a pilot study conducted in a driver retraining facility in one Chinese city where people who have had their licence suspended for accrual of 12 demerit points in a one year period must attend compulsory retraining in order to regain their licence. A sample of 239 suspended drivers responded to an anonymous questionnaire that sought information about preferred driving speeds and perceptions of safe driving speeds across two speed zones. Responses indicated that speeds higher than the posted limits were commonly reported, and that there was incongruence between preferred and safe speeds, such that a greater proportion of drivers reported preferred speeds that were substantially faster than what were reported as safe speeds. Participants with more driving experience reported significantly fewer crashes than newly licensed drivers (less than 2 years licensed) but no differences were found in offences when compared across groups with different levels of driving experience. Perceptions of risky behaviours were assessed by asking participants to describe what they considered to be the most dangerous on-road behaviours. Speeding and drink driving were the most commonly reported by far, followed by issues such as fatigue, ignoring traffic rules, not obeying traffic rules, phone use while driving, and non-use of seatbelts, which attracted an extremely low response which seems consistent with previously reported low belt wearing rates, unfavourable attitudes towards seatbelt use, and low levels of enforcement. Finally, observations about culturally specific considerations are made from previous research conducted by the authors and others. Specifically, issues of saving face and the importance and pervasiveness of social networks and social influence are discussed with particular regard to how any future countermeasures need to be informed by a thorough understanding of Chinese customs and culture.     

Dominant role of drivers’ attitude in prevention of road traffic crashes: A study on knowledge,attitude, and practice of drivers in Iran

Objective

Evaluating the relation between Iranian drivers’ knowledge, attitude, and practice (KAP) regarding traffic regulations, and their deterministic effect on road traffic crashes (RTCs).

Setting

Two cities of Tehran and Zahedan, Iran.

Methods

A cross-sectional study was designed. Using a simplified cluster sampling design, 2200 motor vehicle drivers including 1200 in Tehran and 1000 in Zahedan were selected. Sixty locations in Tehran and 50 in Zahedan were chosen. In each pre-identified location, 20 adult drivers were approached consecutively. A questionnaire developed by researchers was filled by each participant. The questionnaire had four sections including items assessing the demographics, knowledge, attitude and practice of drivers toward traffic regulations. Logistic regression analysis was used to evaluate the relationship between the RTCs and KAP variables.

Results

The study sample consisted of 619 (28.1%) occupational and 1580 (71.8%) private drivers. Among them, 86.4% were male. The median age was 33.6 ± 10.83. Drivers in Tehran and Zahedan had no significant differences between their mean scores of KAP items of the questionnaire. Higher knowledge, safer attitude, and safer practice were associated with a decreased number of RTC. After adjusting for possible confounders, increase of one standard deviation in attitude and practice scores (but not knowledge) resulted in 26.4% and 18.5% decrease in RTC, respectively. Finally, considering knowledge, attitude and practice of drivers in one model to assess their mutual effect, it was shown that only attitude is significantly associated with a decrease of RTC (OR = 0.76, P = 0.007).

Conclusion

Increase in attitude and practice accompanied with decreased number of RTCs in Iranian drivers. Specifically, drivers’ attitude had the crucial effect. It is not knowledge and standard traffic education; rather it is how such education is registered as an attitude that translates what is being learned into actions. Without safer attitude, even safer self-reported practice will not result in lower RTCs.     

Exploring the effects of attitudinal and perception characteristics on drinking and driving non-compliant behaviour

The objective of this paper is to examine a number of factors (observed and latent) that might have a causal effect on drinking and driving (D&D) behaviour. Face-to-face surveys were conducted among patrons at bars and cafeterias and 305 valid questionnaires were filled. A confirmatory factor analysis was performed so as to identify the latent constructs and a mixed structural equation model was developed. From the analysis it came up that non-compliant behaviour of D&D is limited at older ages, also associated with high levels of income and car availability. Though men are consuming more alcohol, women seem to be more prone in driving under the influence (DUI) of alcohol. Furthermore, it was found that people who strongly support the examined interventions in the study (e.g. better enforcement, more traffic safety campaigns, stricter penalties) are more unlikely to drive after drinking compare to those who have some objections. Finally, it was not found any statistically significant relation between individuals’ level of awareness and D&D behaviour.     

Effect of consecutive driving on accident risk: A comparison between passenger and freight train driving

This study combined driver-responsible accidents with on-board driving hours to examine the effect of consecutive driving on the accident risk of train operations. The data collected from the Taiwan Railway Administration for the period 1996–2006 was used to compute accident rates for varied accumulated driving hours for passenger and freight trains. The results showed that accident risk grew with increased consecutive driving hours for both passenger and freight trains, and doubled that of the first hour after four consecutive hours of driving. Additional accident risk was found for freight trains during the first hour due to required shunting in the marshalling yards where there are complex track layouts and semi-automatic traffic controls. Also, accident risk for train driving increased more quickly over consecutive driving hours than for automobile driving, and accumulated fatigue caused by high working pressure and monotony of the working environment are considered to be the part of the reason. To prevent human errors accidents, enhancing safety equipment, driver training programs, and establishing a sound auditing system are suggested and discussed.     

The perceptions of young rural drivers in NSW,Australia of speeding and associated risk: A mixed methods study

The study, using mixed methodology, examined perceptions of risk associated with speeding in young rural people. Focus groups discussions (age range 16–24) in which speeding was identified as often being an involuntary driving behaviour, informed the development of a survey instrument. The survey was conducted with two groups of young people, one rural (n = 217) and another semi-rural (n = 235). The results from both the focus groups and surveys indicate that young rural drivers had specific attitudes to speeding, when compared with other risk factors for crashing. Speeding behaviour was viewed as both acceptable and inevitable. Males and those from a rural area viewed speeding, and reducing trip time when compared to that of a peer, to be less risky than did females and those who lived in a semi-rural area. Speeding was considered to be less risky than drink driving. These perceptions of speeding may contribute to the crash rates on rural roads involving young, local drivers and need to be considered in interventions or educational programmes which aim to reduce the rural road crash rate.     

Willingness to pay for road safety and estimates of the risk of death: evidence from a Swedish contingent valuation study

We examine how WTP for a reduction in road-mortality risk varies with different individual characteristics and how subjective mortality-risk estimates differ from objective (statistical) mortality-risk values. Using data from a Swedish contingent valuation study, we find some support that WTP declines with age and background risk, but we find no support that WTP varies with health status. Further, we find that respondents underassess their own mortality risks, both road- and total-mortality risks, compared to the objective risk measures for Sweden at the time of the survey.     

Findings from the Candrive/Ozcandrive study: Low mileage older drivers,crash risk and reduced fitness to drive

Previous research has found that only older drivers with low annual driving mileages had a heightened crash risk relative to other age groups. These drivers tend to drive mainly in urban areas, where the prevalence of complex traffic situations increases crash risk. However it might also be that some drivers may have reduced their driving due to perceived or actual declines in driving fitness.