Road accidents caused by sleepy drivers: Update of a Norwegian survey

The current study tests, updates and expands a model of factors associated with sleepy driving, originally based on a 1997 survey of accident-involved Norwegian drivers (Sagberg, F., 1999. Road accidents caused by drivers falling asleep. Accident Analysis & Prevention 31, 639–649). The aim is to establish a robust model to inform measures to tackle sleepy driving. The original questions on (i) tiredness-related accidents and (ii) incidents of sleep behind the wheel in the last 12 months were again posed in 2003 and 2008, in independent surveys of Norwegian drivers involved in accidents reported to a large insurance company. According to those drivers at-fault for the accident, tiredness or sleepiness behind the wheel contributed to between 1.9 and 3.9 per cent of all types of accident reported to the insurance company across these years. Accident-involved drivers not at fault for the accident reported a reduction in the incidence of sleep behind the wheel for the preceding year, decreasing from 8.3 per cent in 1997 to 2.9 per cent in 2008. The reasons for this are not clear. According to logistic regression analysis of survey responses, the following factors were robustly associated with road accidents involving sleepy driving: driving off the road; good road conditions; longer distance driven since the start of the trip; and fewer years with a driving licence. The following factors are consistently associated with reports of sleep behind the wheel, whether or not it leads to an accident: being male; driving further per year; being younger; and having sleep-related health problems. Taken together these findings suggest that young, inexperienced male drivers who drive long distances may be a suitable target for road safety campaigns aimed at tackling sleepy driving.     

Factors associated with falling asleep at the wheel among long-distance truck drivers

Data on the prevalence and hypothesized predictors of falling asleep while driving were gathered through face-to-face interviews with 593 long-distance truck drivers randomly selected at public and private rest areas and routine roadside truck safety inspections. Hypothesized predictor variables related to drivers' typical work and rest patterns, extent of daytime and night-time drowsiness, symptoms of sleep disorder, measures of driving exposure, and demographic characteristics. A sizeable proportion of long-distance truck drivers reported falling asleep at the wheel of the truck: 47.1% of the survey respondents had ever fallen asleep at the wheel of a truck, and 25.4% had fallen asleep at the wheel in the past year. Factor analysis reduced the large set of predictors to six underlying, independent factors: greater daytime sleepiness; more arduous schedules, with more hours of work and fewer hours off-duty; older, more experienced drivers; shorter, poorer sleep on road; symptoms of sleep disorder; and greater tendency to night-time drowsy driving. Based on multivariate logistic regression, all six factors were predictive of self-reported falling asleep at the wheel. Falling asleep was also associated with not having been alerted by driving over shoulder rumble strips. The results suggest that countermeasures that limit drivers' work hours and enable drivers to get adequate rest and that identify drivers with sleep disorders are appropriate methods to reduce sleepiness-related driving by truck drivers.     

Fatal traffic accidents among trailer truck drivers and accident causes as viewed by other truck drivers

Causality factors, the responsibility of the driver and driver fatigue-related factors were studied in fatal two-vehicle accidents where a trailer truck driver was involved during the period of 1991-1997 (n = 337). In addition, 251 long-haul truck drivers were surveyed in order to study their views regarding contributing factors in accidents involving trucks and the development of possible countermeasure against driver fatigue. Trailer truck drivers were principally responsible for 16% of all the accidents. Younger driver age and driving during evening hours were significant predictors of being principally responsible. In addition, the probability of being principally responsible for the accident increased by a factor of over three if the driver had a chronic illness. Prolonged driving preceding the accident, accident history or traffic offence history did not have a significant effect. Only 2% of the drivers were estimated to have fallen asleep while driving just prior to the accident, and altogether 4% of the drivers had been tired prior to the accident. Of the drivers 13% had however, been driving over 10 h preceding the accident (which has been criminally punishably in Finland since 1995 under the EC regulation) but no individual factors had a significant effect in predicting prolonged driving. The surveyed views regarding causes of truck accidents correspond well with the accident analysis. Accidents were viewed as being most often caused by other road users and driver fatigue was viewed to be no more than the fifth (out of eight) common cause of accidents. The probability of viewing fatigue as a more common cause increased significantly if the driver had experienced fatigue-related problems while driving. However, nearly half of the surveyed truck drivers expressed a negative view towards developing a technological countermeasure against driver fatigue. The negative view was not related to personal experiences of fatigue-related problems while driving.     

Driver risk factors for sleep-related crashes

A population-based case-control study was carried out to examine driver risk factors for sleep-related motor vehicle crashes. Cases included 312 drivers involved in recent North Carolina crashes and identified on police reports as asleep at the time of the crash and 155 drivers identified as fatigued. Controls were 529 drivers also involved in recent crashes but not identified as asleep or fatigued, and 407 drivers not involved in recent crashes. All drivers were contacted for brief telephone interviews. Results showed that drivers in sleep-related crashes were more likely to work multiple jobs, night shifts, or other unusual work schedules. They averaged fewer hours sleep per night, reported poorer quality sleep, were less likely to feel they got enough sleep, were sleepier during the day, drove more often late at night, and had more prior instances of drowsy driving. Compared to drivers in non-sleep-related crashes, they had been driving for longer times, been awake more hours, slept fewer hours the night before, and were more likely to have used soporific medications. Knowledge of specific risk factors for sleep-related crashes is an important first step in reducing the thousands of deaths and injuries each year in the US attributed to drowsy driving.     

The contributions of sleep-related risk factors to diurnal car accidents

This study was intended to estimate the presence and number of individual sleep-related risk factors in a sample of diurnal car accidents and to analyze the extent to which these risk factors tended to be more represented in diurnal accidents involving only one vehicle, involving young drivers or occurring on non-urban roads. Two hundred fifty-three drivers involved in diurnal accidents were interviewed immediately after the accidents to assess their sleepiness-related personal conditions and the circumstances prior to the accident (i.e., individual sleep-related risk factors), such as poor sleep, changes in habitual sleeping patterns, prolonged wakefulness, self-reported acute sleepiness and daytime sleepiness, night-shift jobs and insomnia.     

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 2 h 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 200 s 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.     

Fatal accidents at railway level crossings in Great Britain 1946-2009

This paper investigates fatal accidents and fatalities at level crossings in Great Britain over the 64-year period 1946–2009. The numbers of fatal accidents and fatalities per year fell by about 65% in the first half of that period, but since then have remained more or less constant at about 11 fatal accidents and 12 fatalities per year. At the same time other types of railway fatalities have fallen, so level crossings represent a growing proportion of the total. Nevertheless, Britain's level crossing safety performance remains good by international standards.The paper classifies level crossings into three types: railway-controlled, automatic, and passive. The safety performance of the three types of crossings has been very different. Railway-controlled crossings are the best-performing crossing type, with falling fatal accident rates. Automatic crossings have higher accident rates per crossing than railway controlled or passive crossings, and the accident rates have not decreased. Passive crossings are by far the most numerous, but many have low usage by road users. Their fatal accident rate has remained remarkably constant over the whole period at about 0.9 fatal accidents per 1000 crossings per year.A principal reason why fatal accidents and fatalities have not fallen in the second half of the period as they did in the first half is the increase in the number of automatic crossings, replacing the safer railway controlled crossings on some public roads. However, it does not follow that this replacement was a mistake, because automatic crossings have advantages over controlled crossings in reducing delays to road users and in not needing staff.Based on the trends for each type of crossing and for pedestrian and non-pedestrian accidents separately, in 2009 a mean of about 5% of fatal accidents were at railway controlled crossings, 52% were at automatic crossings, and 43% were at passive crossings. Fatalities had similar proportions. About 60% of fatalities were to pedestrians.A simple comparison of automatic railway level crossings and signalised road intersections found that in 2005 the numbers of fatalities per 1000 crossings or intersections were similar.     

Novice drivers' accidents and violations--a failure on higher or lower hierarchical levels of driving behaviour

The study compared accident and offence rates of 28 500 novice drivers in Finland. The purpose was to study differences in accident and offence rates between male and female novice drivers of different age. The drivers reported in a mailed questionnaire, how many accidents they had been involved in and how much they had driven during their whole driving career. All the drivers had a driving experience of 6–18 months. Information about offences for a 2-year period was obtained from an official register of drivers' licences. The drivers were classified into three age brackets: 18–20, 21–30 and 31–50 years. The effect of driving experience was controlled by dividing the drivers into different mileage brackets. The data was analysed and the results were discussed in the framework of the hierarchical model of driving behaviour. Young novice drivers and especially young male drivers showed more problems connected to the higher hierarchical levels of driving behaviour than middle-aged novice drivers. The number of accidents and offences was highest among the young males and their accidents took place more often at night than female or older drivers' accidents. Female drivers showed more problems connected to the lower hierarchical levels of driving behaviour, e.g. problems in vehicle handling skills. Ways of measuring accident risk of different driver groups were also discussed, as well as the usefulness and reliability of self-reports in accident studies.     

Sleep debt,sleepiness and accidents among males in the general population and male professional drivers

Men from the general population and male professional lorry and bus drivers were surveyed with regard to sleep habits and motor vehicle and other types of accidents. A random sample of 4000 men in the general population of Dalarna County in mid-Sweden were mailed a questionnaire and served as referents. A total of 1389 male professional lorry and bus drivers from this county responded to the same questionnaire. A total of 161 of the drivers also underwent a sleep study in their homes.The proportion of total accidents was higher among the professional drivers as compared with the males in the population, P=0.03. Reports on traffic accidents were the same in both groups, but the professional drivers reported more accidents at leisure compared with referents, P<0.0001. Accidents of any kind, traffic accidents included, among those affected by both snoring and apneas, were not reported more in either of the groups. At the sleep study, 17% of those examined received the diagnosis of obstructive sleep-apnea syndrome (OSAS).The professional drivers reported proportionally more sleep debt than the referents, P<0.001. Among referents, traffic accidents at leisure, traffic accidents while commuting and accidents at work increased in proportion to sleep debt (P<0.001, 0.006 and 0.002, respectively). The finding that self-perceived sleep debt may have an adverse effect on males in the general population and male professional drivers concerning accident likelihood should have an impact on prevention. These results stress the need to educate the general population on the importance of complying with our biological need of sleep.     

Car drivers' attitudes towards motorcyclists: a survey

Motorcyclists are over-represented in UK traffic accident statistics. Many car–motorcycle accidents are however due to the inappropriate actions of car drivers. It is predicted that car drivers at risk of collision with motorcycles have divergent attitudes and beliefs about motorcyclists compared to safer drivers, which may lead to a deficient mental model guiding their interactions with motorcyclists. To assess car drivers’ attitudes towards motorcyclists, a survey was undertaken. Respondents filled in 26 general and motorcycle-related items and the 24 items of the reduced Driver Behaviour Questionnaire. Compared to an experienced dual driver group (who both drive cars and ride motorcycles), all other drivers showed divergent beliefs and attitudes. Four factors were extracted from the motorcycle items: negative attitudes, empathic attitudes, awareness of perceptual problems, and spatial understanding. Car drivers with a moderate amount of experience (between 2 and 10 years driving) held the most negative views and reported the most violations. The results have lead to several suggestions for interventions aimed at decreasing the divergence between drivers’ perceptions of motorcyclists, and the perceptions of experienced dual drivers.     

Characteristics of motor vehicle accidents resulting in spinal cord injury

The majority of cases of spinal cord injury (SCI) occur during car crashes. Yet, relatively little is known about the precise accident factors involved. The present study investigated 30 cases of SCI in automobile drivers that occurred in a series of 91 spinal cord injuries. A matched control group was also studied. SCI drivers were not different from controls in terms of mortality, number of rollover crashes, alcohol use, citations for contributing human factors, nighttime accidents, or unfavorable weather and road conditions. However, SCI drivers less frequently used restraints. Results are discussed in terms of preventive measures, specifically, those concerning restraint use, alcohol use, and driving behavior.     

Exploring the effects of lifestyle, sleep factors and driving behaviors on sleep-related road risk: A study of Greek drivers

Purpose

The present study explored the effect of various lifestyle patterns and sleep-related factors on the sleep-related road risk. Sleep-related factors included daytime sleepiness, drowsy driving and quality/quantify of sleep.

Methods

A sample of 1366 non-professional drivers aged 19–65 was selected from the broader Athens area of Greece, using stratified random sampling. The questionnaire solicited information on the participants’ socio-demographic characteristics, driving background, lifestyle patterns, sleep quality and quantity, daytime sleepiness, drowsy driving behavior and sleep-related road risk.

Results

Sleep-related road risk was affected by gender, quantity of night sleep and drowsy driving behavior. Drowsy driving behavior was shown to be related to gender, daytime sleepiness, sleep quality and the lifestyle of “amusement”. Daytime sleepiness was correlated with sleep quality and the lifestyles of “amusement” and “sport”. Finally, sleep quality and quantity were significantly affected by the lifestyles of “amusement” and “yuppies-workaholic”.

Conclusion

The current study has identified a number of risk factors in sleep-related crash risk in the general population of drivers. By raising public awareness the health and safety community can play an important role in reducing, if not preventing, the consequences of this public health problem.     

Convicted of fatigued driving: Who, why and how?

Fatigue is a major cause of road traffic accidents. However, due to the blurred concept of fatigue and the lack of reliable testing devices (cf. the breath analyzer for alcohol levels), it is extremely difficult to incorporate fatigue in operationalized terms into either traffic or criminal law. Even though the Finnish Road Traffic Act explicitly forbids driving while tired, it is done only on a general level among other factors (sickness, etc.) that impair a driver's fitness to drive (Article 63). The present study was done to investigate the circumstances of fatigue driving offenses. From the Finnish Vehicle Administration driver record database we extracted all drivers (N = 768) punished under Article 63 from 2004-2005. Of these drivers, 90.4% committed a fatigue-related traffic offense. Accidents, predominantly single vehicle, were the most common (92.5%) consequence of fatigued driving. Although fatigue-related accidents are thought to be serious, our data shows that most of the accidents (81.6%) did not involve personal injuries. Almost every twentieth driver was punished because his vehicle was drifting on the road. The presence of alcohol or drugs was noted in 13% of the cases. Only 3.1% of the punished drivers officially denied being tired or falling asleep. Young men (≤35 yrs) represented 50% of all punished drivers. Time of day and seasonal effects were clear in this data. This study shows that even without a reliable fatigue detector and unambiguous criteria for recognizing the contribution of fatigue to accident causation, Finnish police and the courts punish a significant number of drivers every year on the basis of fatigue.     

The traffic behaviour of elderly male automobile drivers in Gothenburg,Sweden

406 drivers over 60 years of age with automobile licences issued in Gothenburg, Sweden, were asked by a questionnaire about their driving habits in 1971. 126 drivers around 40 years of age have constituted a comparison group. A large proportion of the older drivers declared that they no longer drove their cars. More than half the number of drivers over 75 years of age and a quarter of the drivers between 65 and 69 years of age had given up driving voluntarily because of age and illness. Self-selection thus seems to be one of several factors of great importance when judging the traffic safety risks of elderly drivers. The annual distance driven by the older driver groups was shorter than in the younger age-group. The older drivers used their cars for other purposes than younger drivers and they also avoided driving in darkness, on icy roads, and in unknown cities to a far greater extent than younger drivers. The total number of accidents and offences during the older drivers' whole life-span as drivers was lower than the corresponding figures in the younger age-group. In our opinion this may depend on the shorter annual distance driven by the older drivers, the change in traffic density in the investigation area, but also to a great extent on the older drivers awareness of their reduced capacity. Their accident and offence rate during a three-year-period is quite similar to the rate in the comparison group.     

Predicting at-fault car accidents of older drivers

Considerable research shows car accidents are difficult to predict using screening tests. The objective of this exploratory study is to determine whether detailed accident analysis taking into account the specific accident type might enhance the predictive power of a standardised road test and a set of selected neuropsychological tests. Moreover, this study addresses the validity and reliability of performance-based driving evaluation. The sample consisted of 84 older drivers between 65 and 96 years of age who were referred for a fitness-to-drive evaluation. Using discriminant analyses, the subjects were classified as drivers with and without at-fault accidents. We compared the accuracy of neuropsychological tests and a road test for postdicting all accidents, accidents classified into two categories and accidents classified into four different categories. The percentages of correctly classified subject were highest at the level of the most detailed classification. These results suggest that, although accident prediction is difficult, the predictability of car accidents by neurocognitive measurements and a road test increases when the kind of accident is specified.     

Perception of the risk of an accident by young and older drivers

Young drivers are significantly overrepresented among all drivers involved in traffic accidents and fatalities. Excessive risk taking by young drivers appears to be largely responsible for this disproportionate involvement. This excessive risk taking could be due to being more willing to take risks than older drivers are, failing to perceive hazardous situations as being as dangerous as older drivers do or both causes. This paper reports the results of a study which attempted to determine whether misperception of risk could be an explanation for the high rates of traffic accidents among youth by testing whether young drivers perceive driving to be less hazardous than do older drivers. Three different methods of estimating the risk of accident involvement were used to compare risk estimates of young and older drivers. The methods included general questions about accident involvement, rating the riskiness of ten specific driving situations illustrated in still photographs, and rating the riskiness of fifteen videotaped driving situations. Young drivers perceived their own chances of an accident to be significantly lower than those of both their peers and older male drivers, while older male drivers saw their chances of accident involvement as comparable to those of their male peers and less than those of young male drivers. These findings lend support to the thesis that young male drivers are overrepresented in traffic accidents at least in part because they fail to perceive specific driving situations as being as risky as older drivers perceive them.     

Driving strategies among younger and older drivers when encountering children

Results are presented of a study into how drivers say they behave and how they actually behave in traffic situations in which children are involved. An analysis was made of the most important types of encounters in which drivers become involved in accidents with children. On the basis of accident surveys and psychological theories on information processing, it was assessed by means of a questionnaire what knowledge drivers have concerning their own behavior in these situations, as well as their expectations about typical child behavior. Actual behavior of drivers in these situations was investigated by assessing video recordings of their behavior in driving a one hour standard track through residential areas. From the questionnaire it appeared that younger drivers reported more frequently dangerous behavior than older drivers. The recordings showed that younger drivers also behaved more dangerously during child encounters. This result could not be explained by differences in speed, but could by the fact that younger drivers detected the children less frequently than older drivers. Implications for the contents of mass media campaigns and their evaluation are discussed.     

The effect on accident risk of a change in driver education in Denmark.

Driver education in Denmark was changed radically in 1986. An evaluation study was undertaken to see whether the new education concept had had any effect on the development in accidents. In an earlier part of the study, it was found that after the change in education the number of accidents involving 18-19-year-olds in the official statistics had decreased more than that involving mature drivers. This fact could not solely be attributed to changes in population size, changes in exposure, mild winters in the period after the change, etc. It seemed, therefore, reasonable to attribute the effect to the changes in driver education. In the present study, two groups of new car drivers trained according to the old and new programs respectively--were followed-up with four questionnaires through their first 5.5 years as drivers. The decrease in accidents found in the official statistics was also found for the drivers in the questionnaire study. The decrease is mainly concentrated in the 1st year of driving, and is found in multiple-vehicle accidents and manoeuvring accidents. The number of single-vehicle accidents did not change. Those who received training which satisfied a number of the basic requirements in the new education program, had a lower accident risk than those whose education did not meet these requirements. This can be seen as an indication that the decrease in accidents is explainable, at least in part, by changes in driver education.     

Women drivers' behaviour, socio-demographic characteristics and accidents.

The purpose of this study was to examine factors which affect driving behaviour and accident rates in women in Australia. Two groups of women (aged 18-23 and 45-50 years) participating in the Australian Longitudinal Study on Women's Health, completed a mailed questionnaire on driver behaviour and road accidents. Self reported accident rates in the last 3 years were 1.87 per 100,000 km for the young drivers (n = 1199) and 0.59 per 100,000 km for the mid-age drivers (n = 1564); most accidents involved damage only, not injury. Mean scores for lapses obtained using the Driver Behaviour Questionnaire, were similar in the two age groups and similar to those found in other studies. In contrast, scores for errors and violations for the young women were higher than for the mid-age group and previous reports using the same instruments. Riskier driving behaviour among young women was associated with stress and habitual alcohol consumption. In the mid-age group, poorer driver behaviour scores were related to higher levels of education, feeling rushed, higher habitual alcohol consumption and lower life satisfaction scores. Accident rates in both groups were significantly related to lapses. Women born in non-English speaking countries had significantly higher risk of accidents compared to Australian-born women: relative risk = 3.40, 95% confidence interval (1.93, 5.98) for the young drivers; relative risk = 1.77, 95% confidence interval (1.11, 2.83) for mid-age drivers. These findings support the need for road safety campaigns targeted at young women to reduce dangerous driving practices, such as speeding, 'tail gating' and overtaking on the inside. There is also a need for further research to understand how lifestyle characteristics are associated with higher risk of accidents and to explore factors which might account for the higher risk for women drivers who were born overseas.