Teen driver crash risk and associations with smoking and drowsy driving

Understanding the drowsy driving crash patterns from correspondence regression analysis

Drowsy driving-related crashes have been a key concern in transportation safety. In Louisiana, 14% (1,758 out of 12,512) of police-reported drowsy driving-related crashes during 2015-2019 resulted in injury (fatal, severe, or moderate). Amid the calls for action against drowsy driving by national agencies, it is of paramount importance to explore the key reportable attributes of drowsy driving behaviors and their potential association with crash severity.

METHOD

This study used 5-years (2015-2019) of crash data and utilized the correspondence regression analysis method to identify the key collective associations of attributes in drowsy driving-related crashes and interpretable patterns based on injury levels.

RESULTS

Several drowsy driving-related crash patterns were identified through crash clusters - afternoon fatigue crashes by middle-aged female drivers on urban multilane curves, crossover crashes by young drivers on low-speed roadways, crashes by male drivers during dark rainy conditions, pickup truck crashes in manufacturing/industrial areas, late-night crashes in business and residential districts, and heavy truck crashes on elevated curves. Several attributes - scattered residential areas indicating rural areas, multiple passengers, and older drivers (aged more than 65 years) - showed a strong association with fatal and severe injury crashes.

PRACTICAL APPLICATIONS

The findings of this study are expected to help researchers, planners, and policymakers in understanding and developing strategic mitigation measures to prevent drowsy driving.

How Tired is Too Tired to Drive? A Systematic Review Assessing the Use of Prior Sleep Duration to Detect Driving Impairment

Driver fatigue is a contributory factor in approximately 20% of vehicle crashes. While other causal factors (eg, drink-driving) have decreased in recent decades due to increased public education strategies and punitive measures, similar decreases have not been seen in fatigue-related crashes. Fatigued driving could be managed in a similar way to drink-driving, with an established point (ie, amount of prior sleep) after which drivers are "deemed impaired". This systematic review aimed to provide an evidence-base for the concept of deemed impairment and to identify how much prior sleep may be required to drive safely. Four online databases were searched (PubMed, Web of Science, Scopus, Embase). Eligibility requirements included a) measurement of prior sleep duration and b) driving performance indicators (eg, lane deviation) and/or outcomes (eg, crash likelihood). After screening 1940 unique records, a total of 61 studies were included. Included studies were categorised as having experimental/quasi-experimental (n = 21), naturalistic (n = 3), longitudinal (n = 1), case-control (n = 11), or cross-sectional (n = 25) designs. Findings suggest that after either 6 or 7 hours of prior sleep, a modest level of impairment is generally seen compared with after ≥ 8 hours of prior sleep (ie, well rested), depending on the test used. Crash likelihood appears to be ~30% greater after 6 or 7 hours of prior sleep, as compared to individuals who are well rested. After one night of either 4 or 5 hours of sleep, there are large decrements to driving performance and approximately double the likelihood of a crash when compared with well-rested individuals. When considering the scientific evidence, it appears that there is a notable decrease in driving performance (and associated increase in crash likelihood) when less than 5h prior sleep is obtained. This is a critical first step in establishing community standards regarding the amount of sleep required to drive safely.

Drowsy Driving, Sleep Duration, and Chronotype in Adolescents

OBJECTIVE

To determine whether self-reported drowsy driving was associated with an evening chronotype, a biologically-based difference in circadian sleep-wake timing, and shorter school-night sleep duration in a sample of high school drivers.

STUDY DESIGN

Cross-sectional observational data were obtained from an online survey in spring 2015 of 431 drivers, age 15.5-18.7 years, attending Fairfax County (Virginia) Public schools. Drowsy driving was defined as having ever "driven a car or motor vehicle while feeling drowsy" in the last year. School-night sleep duration was calculated from school-night bedtime and wake time. Those with scores in the lower and upper tertiles of the Morningness-Eveningness Scale for Children were designated as having an evening or morning chronotype, respectively.

RESULTS

Among survey respondents, 63.1% drove at least several times a week and 47.6% reported drowsy driving. The covariate-adjusted prevalence of drowsy driving was 13.9% (95% CI 3.0%-24.9%) higher in students who slept <7 hours on school-nights than in those who slept 8 or more hours. Compared with those with a morning chronotype, the adjusted prevalence of drowsy driving was 15.2% (95% CI 4.5%-25.9%) higher among those with an evening chronotype.

CONCLUSION

Among adolescent drivers, both an evening chronotype and shorter school-night sleep duration were associated with more frequent reports of drowsy driving. Interventions to improve the timing and duration of nighttime sleep in adolescents may reduce the occurrence of drowsy driving.

Smoking Patterns and Willingness to Quit: A Cross-sectional Study in Al Ain City, UAE

Background:

Tobacco use is the major cause of preventable morbidity and mortality. The main objectives of this study were to identify smokers willing to participate in quit smoking campaigns using social media and to identify smoking habits of everyday smokers in Al Ain City, United Arab Emirates (UAE).

Research Design and Methods:

Everyday smokers from Al Ain city of the UAE were surveyed in different locations of the city including malls and specialized tobacco-selling shops. They were interviewed using a semi-structured survey and the information was recorded by one assessor. The information gathered included type and frequency of tobacco use, smoking history and habits, quitting history, desire to quit, and the preferred communication platform.

Result:

A total of 412 regular adult smokers were interviewed in which the majority (95%) reported first smoking at or before the age of 28 years. Participants were mainly UAE nationals (33.7%), Egyptians (14.1%), Syrians (12.9%), and Jordanians (10.9%). Manufactured cigarettes were the main form of tobacco consumption (59.5%), and smoking was mainly solitary (56.3%) and at home (26.3%) and coffee shops (24.9%). The majority of interviewed subjects (76.7%; 95% confidence interval [CI]: 72.4%–80.5%) expressed their interest to quit smoking in the future and 55.3% (95% CI: 50.5%–60.2%) were ready to get involved immediately in a smoking cessation program. Of those, 80.3% (95% CI: 74.6%–84.9%) preferred WhatsApp for receiving smoking cessation motivational education.

Conclusion:

The majority of smokers started at younger ages, which warrant the age of smoking restriction to be raised to 29 years instead of 18 years by the health authority. Everyday smokers were aware of the potentially hazardous effects of tobacco smoking and many were willing to accept help to quit smoking that involves the use of WhatsApp.

Association between Smoking and Unintentional Injuries among Korean Adults

Using a cross-sectional representative national survey, we evaluated the relationship between cigarette smoking and unintentional injuries among Korean adults. We used data from the 2009 Korean Community Health Survey. Smoking status was defined as never smokers, ex-smokers, and current smokers. Current smokers were categorized into light daily smokers (1–10 cigarettes/day), moderate daily smokers (11–20 cigarettes/day), or heavy daily smokers (≥21 cigarettes/day). We used the Poisson regression model with a robust variance estimation to estimate prevalence rate ratios (PRR) and corresponding 95% confidence interval (95% CI). After adjusting for demographic characteristics, socioeconomic variables, lifestyle variables, and health status variables, former smokers (PRR, 1.19, 95% CI 1.11–1.28), light daily smokers (PRR 1.22, 95% CI 1.13–1.32), moderate daily smokers (PRR 1.33, 95% CI 1.24–1.42), and heavy daily smokers (PRR 1.40, 95% CI 1.25–1.57) had an increased risk for unintentional injuries compared with non-smokers. In conclusion, cigarette smoking is associated with unintentional injuries in a dose-response manner in Korean adults. The findings suggest that community smoking cessation programs may reduce morbidity and mortality from unintentional injuries.

Does Cigarette Smoking Increase Traffic Accident Death During 20 Years Follow-up in Japan? The Ibaraki Prefectural Health Study

Background

Annually, more than 1.2 million deaths due to road traffic accidents occur worldwide. Although previous studies have examined the association between cigarette smoking and injury death, the mortality outcome often included non-traffic accident-related deaths. This study aimed to examine the association between cigarette smoking and traffic accident death.

Methods

We conducted a prospective cohort study using data from the Ibaraki Prefectural Health Study conducted from 1993 through 2013. The cohort included 97,078 adults (33,138 men and 63,940 women) living in Ibaraki Prefecture who were aged 40–79 years at an annual health checkup in 1993. We divided participants into four smoking status groups: non-smokers, ex-smokers, and current smokers who smoked <20 and ≥20 cigarettes per day. Hazard ratios (HRs) of traffic accident death were calculated using a Cox proportional hazards model.

Results

During 20 years of follow-up, the average person-years of follow-up were 16.8 and 18.2 in men and women, respectively. Among men, after adjusting for age and alcohol intake, HRs for traffic accident death among current smokers of <20 cigarettes/day and ≥20 cigarettes/day compared to non-smokers were 1.32 (95% confidence interval [CI], 0.79–2.20) and 1.54 (95% CI, 0.99–2.39), respectively. In contrast, among women, we found no association between smoking status and traffic accident deaths.

Conclusion

In this prospective cohort study, we found a positive association, though marginally significant, between smoking and traffic accident death among men in Japan. Among women, because of the smaller number of deaths among smokers, adequate estimation could not be obtained.

Is there a link between motor vehicle collisions and being a cigarette smoker in Canada? Analysis of survey data from Ontario from 2002 to 2014

OBJECTIVE

Although most research on drugs and driving has focused on the use of alcohol and cannabis, research that has been conducted on cigarette smoking and collisions has found that smokers have an increased collision involvement. Studies dating from 1967 through 2013 have shown a crude relative risk of about 1.5 among smokers compared to nonsmokers. In Canada, the association between smoking and collisions has not been recently investigated. Studies that have examined the association between smoking and collisions often did not control for all confounding factors, such as alcohol use and driving exposure, which have been associated with increased collision rates. Additionally, a number of these studies were examined in countries and at times when prevalence of smoking was much higher than is currently the case in Canada. The purpose of this research is to examine the association between self-reported current smoking and past-year collision involvement, controlling for confounding factors, in a large representative sample of adult drivers in Ontario, Canada, from 2002 and 2014.

METHOD

Data are based on the Centre for Addiction and Mental Health (CAMH) Monitor, an ongoing, rolling telephone survey of Ontario adults that provides epidemiological surveillance of indicators related to alcohol, tobacco, and other drug use, as well as physical and mental health. The survey uses random-digit-dialing methods via Computer-Assisted Telephone Interview, with response rates over 50%.

RESULTS

Prevalence of self-reported collision involvement within the past year for 2002-2014 was 8.6% among those who currently smoke compared to 6.5% of nonsmokers. Logistic regression analysis, controlling for the potential confounding effects of sociodemographics, driving exposure measures, drinking frequency, and hazardous alcohol use, found that the overall odds for collision involvement in the preceding year among current smokers for 2002-2014 was 1.27 (95% confidence interval [CI], 1.06-1.53) times that of nonsmokers.

CONCLUSIONS

These findings indicate that despite a substantial reduction in overall prevalence of smoking in Canada, smokers still have a significantly increased odds of collision involvement, even when controlling for alcohol and exposure. Additionally, the results are consistent with the increased odds/risks of motor vehicle collisions found in other countries.

The association of measures of the serotonin system, personality, alcohol use, and smoking with risk-taking traffic behavior in adolescents in a longitudinal study

Studies on the neurobiological basis of risk-taking behavior have most often focused on the serotonin system. The promoter region of the gene encoding the serotonin transporter contains a polymorphic site (5-HTTLPR) that is important for the transcriptional activity, and studies have demonstrated its association with brain activity and behavior. Another molecular mechanism that reflects the capacity of the central serotonin system is the activity of the enzyme monoamine oxidase (MAO) as measured in platelets. The purpose of the present study was to examine how measures of the serotonin system (platelet MAO activity and the 5-HTTLPR polymorphism), personality variables, alcohol use and smoking are associated with risk-taking traffic behavior in schoolchildren through late adolescence. The younger cohort of the longitudinal Estonian Children Personality Behaviour and Health Study (originally n = 583) filled in questionnaires about personality traits, smoking status, alcohol use and traffic behavior at age 15 and 18 years. From venous blood samples, platelet MAO activity was measured radioenzymatically and 5-HTTLPR was genotyped. During late adolescence, subjects with lower platelet MAO activity were more likely to belong to the high-risk traffic behavior group. Male 5-HTTLPRs'-allele carriers were more likely to belong to the high-risk traffic behavior group compared to the l'/l' homozygotes. Other variables predicting risk group were alcohol use, smoking and Maladaptive impulsivity.The results suggest that lower capacity of the serotoninergic system is associated with more risky traffic behavior during late adolescence, but possibly by different mechanisms in boys and girls.

Relationships Between Smoking and Sleep Problems in Black and White Adolescents

Study Objectives

The relationship between sleeping and smoking during adolescence remains unclear and is likely complex. We aim to evaluate the longitudinal reciprocal associations between sleep problems, sleep duration, and smoking among non-Hispanic white (NHW) and non-Hispanic black (NHB) youth.

Design

Prospective cohort study.

Setting

NEXT Generation Health Study.

Participants

A national sample (N = 1394) of NHB and NHW 10th graders were surveyed annually between 2009 (Wave 1) and 2012 (Wave 3).

Interventions

N/A.

Measurements and Results

Past 30-day smoking, chronic difficulty falling asleep, recent difficulty falling asleep, difficulty staying asleep, and weekday and weekend sleep duration were measured at each wave. Using structural equation models, we observed significant autocorrelations over time for sleep problems and sleep duration. We found significant reciprocal, prospective relationships between smoking and sleep problems. The strengths of the relationships differed by race, with a stronger association between sleep problems and subsequent smoking for NHB than NHW youth. Conversely, a stronger association between smoking and subsequent sleep problems for NHW than NHB youth was observed. These association were independent of demographics, snoring or sleep apnea, body mass index, depressive symptoms, alcohol use, and soda consumption.

Conclusions

Reciprocal and prospective relationships exist for youth smoking and sleep problems and duration in both NHW and NHB youth. Further research is needed to unravel the complex relationship between the direct effects of nicotine, lifestyle choices that may link smoking and sleep problems, and racial differences.

Asleep at the Wheel-The Road to Addressing Drowsy Driving

Drowsy driving is a dangerous behavior that leads to thousands of deaths and injuries each year. It is also a controllable factor for drivers. Drivers are capable of modifying this behavior if given sufficient information and motivation. Our goal is to establish a comprehensive and strategic effort to end drowsy driving crashes and deaths. This article highlights some of the conclusions of a unique recent meeting of sleep experts and highway safety professionals and describes the first steps the community has taken and plans to take in the future to address this issue.

Risk of Motor Vehicle Accidents Related to Sleepiness at the Wheel: A Systematic Review and Meta-Analysis

Study Objectives

Sleepiness at the wheel is widely believed to be a cause of motor vehicle accidents. Nevertheless, a systematic review of studies investigating this relationship has not yet been published. The objective of this study was to quantify the relationship between sleepiness at the wheel and motor vehicle accidents.

Methods

A systematic review was performed using Medline, Scopus, and ISI Web of Science. The outcome measure of interest was motor vehicle accident defined as involving four- or two-wheeled vehicles in road traffic, professional and nonprofessional drivers, with or without objective consequences. The exposure was sleepiness at the wheel defined as self-reported sleepiness at the wheel. Studies were included if they provided adjusted risk estimates of motor vehicle accidents related to sleepiness at the wheel. Risk estimates and 95% confidence intervals (95% CIs) were extracted and pooled as odds ratios (ORs) using a random-effect model. Heterogeneity was quantified using Q statistics and the I2 index. The potential causes of heterogeneity were investigated using meta-regressions.

Results

Ten cross-sectional studies (51,520 participants), six case-control studies (4904 participants), and one cohort study (13,674 participants) were included. Sleepiness at the wheel was associated with an increased risk of motor vehicle accidents (pooled OR 2.51 [95% CI 1.87; 3.39]). A significant heterogeneity was found between the individual risk estimates (Q = 93.21; I2 = 83%).

Conclusions

Sleepiness at the wheel increases the risk of motor vehicle accidents and should be considered when investigating fitness to drive. Further studies are required to explore the nature of this relationship.

Systematic review registration number

PROSPERO 2015 CRD42015024805.

Delaying Middle School and High School Start Times Promotes Student Health and Performance: An American Academy of Sleep Medicine Position Statement

ABSTRACT

During adolescence, internal circadian rhythms and biological sleep drive change to result in later sleep and wake times. As a result of these changes, early middle school and high school start times curtail sleep, hamper a student's preparedness to learn, negatively impact physical and mental health, and impair driving safety. Furthermore, a growing body of evidence shows that delaying school start times positively impacts student achievement, health, and safety. Public awareness of the hazards of early school start times and the benefits of later start times are largely unappreciated. As a result, the American Academy of Sleep Medicine is calling on communities, school boards, and educational institutions to implement start times of 8:30 AM or later for middle schools and high schools to ensure that every student arrives at school healthy, awake, alert, and ready to learn.

Relationships Between Smoking and Sleep Problems in Black and White Adolescents

Study Objectives

The relationship between sleeping and smoking during adolescence remains unclear and is likely complex. We aim to evaluate the longitudinal reciprocal associations between sleep problems, sleep duration, and smoking among non-Hispanic white (NHW) and non-Hispanic black (NHB) youth.

Design

Prospective cohort study.

Setting

NEXT Generation Health Study.

Participants

A national sample (N = 1394) of NHB and NHW 10th graders were surveyed annually between 2009 (Wave 1) and 2012 (Wave 3).

Interventions

N/A.

Measurements and Results

Past 30-day smoking, chronic difficulty falling asleep, recent difficulty falling asleep, difficulty staying asleep, and weekday and weekend sleep duration were measured at each wave. Using structural equation models, we observed significant autocorrelations over time for sleep problems and sleep duration. We found significant reciprocal, prospective relationships between smoking and sleep problems. The strengths of the relationships differed by race, with a stronger association between sleep problems and subsequent smoking for NHB than NHW youth. Conversely, a stronger association between smoking and subsequent sleep problems for NHW than NHB youth was observed. These association were independent of demographics, snoring or sleep apnea, body mass index, depressive symptoms, alcohol use, and soda consumption.

Conclusions

Reciprocal and prospective relationships exist for youth smoking and sleep problems and duration in both NHW and NHB youth. Further research is needed to unravel the complex relationship between the direct effects of nicotine, lifestyle choices that may link smoking and sleep problems, and racial differences.

Traffic accidents involving fatigue driving and their extent of casualties

The rapid progress of motorization has increased the number of traffic-related casualties. Although fatigue driving is a major cause of traffic accidents, the public remains not rather aware of its potential harmfulness. Fatigue driving has been termed as a "silent killer." Thus, a thorough study of traffic accidents and the risk factors associated with fatigue-related casualties is of utmost importance. In this study, we analyze traffic accident data for the period 2006-2010 in Guangdong Province, China. The study data were extracted from the traffic accident database of China's Public Security Department. A logistic regression model is used to assess the effect of driver characteristics, type of vehicles, road conditions, and environmental factors on fatigue-related traffic accident occurrence and severity. On the one hand, male drivers, trucks, driving during midnight to dawn, and morning rush hours are identified as risk factors of fatigue-related crashes but do not necessarily result in severe casualties. Driving at night without street-lights contributes to fatigue-related crashes and severe casualties. On the other hand, while factors such as less experienced drivers, unsafe vehicle status, slippery roads, driving at night with street-lights, and weekends do not have significant effect on fatigue-related crashes, yet accidents associated with these factors are likely to have severe casualties. The empirical results of the present study have important policy implications on the reduction of fatigue-related crashes as well as their severity.

The driver, the road, the rules … and the rest? A systems-based approach to young driver road safety

The persistent overrepresentation of young drivers in road crashes is universally recognised. A multitude of factors influencing their behaviour and safety have been identified through methods including crash analyses, simulated and naturalistic driving studies, and self-report measures. Across the globe numerous, diverse, countermeasures have been implemented; the design of the vast majority of these has been informed by a driver-centric approach. An alternative approach gaining popularity in transport safety is the systems approach which considers not only the characteristics of the individual, but also the decisions and actions of other actors within the road transport system, along with the interactions amongst them. This paper argues that for substantial improvements to be made in young driver road safety, what has been learnt from driver-centric research needs to be integrated into a systems approach, thus providing a holistic appraisal of the young driver road safety problem. Only then will more effective opportunities and avenues for intervention be realised.

Insufficient sleep in adolescents and young adults: an update on causes and consequences

Chronic sleep loss and associated sleepiness and daytime impairments in adolescence are a serious threat to the academic success, health, and safety of our nation's youth and an important public health issue. Understanding the extent and potential short- and long-term repercussions of sleep restriction, as well as the unhealthy sleep practices and environmental factors that contribute to sleep loss in adolescents, is key in setting public policies to mitigate these effects and in counseling patients and families in the clinical setting. This report reviews the current literature on sleep patterns in adolescents, factors contributing to chronic sleep loss (ie, electronic media use, caffeine consumption), and health-related consequences, such as depression, increased obesity risk, and higher rates of drowsy driving accidents. The report also discusses the potential role of later school start times as a means of reducing adolescent sleepiness.

"I drove after drinking alcohol" and other risky driving behaviours reported by young novice drivers

BACKGROUND

Volitional risky driving behaviours such as drink- and drug-driving (i.e. substance-impaired driving) and speeding contribute to the overrepresentation of young novice drivers in road crash fatalities, and crash risk is greatest during the first year of independent driving in particular.

AIMS

To explore the: (1) self-reported compliance of drivers with road rules regarding substance-impaired driving and other risky driving behaviours (e.g., speeding, driving while tired), one year after progression from a Learner to a Provisional (intermediate) licence; and (2) interrelationships between substance-impaired driving and other risky driving behaviours (e.g., crashes, offences, and Police avoidance).

METHODS

Drivers (n=1076; 319 males) aged 18-20 years were surveyed regarding their sociodemographics (age, gender) and self-reported driving behaviours including crashes, offences, Police avoidance, and driving intentions.

RESULTS

A relatively small proportion of participants reported driving after taking drugs (6.3% of males, 1.3% of females) and drinking alcohol (18.5% of males, 11.8% of females). In comparison, a considerable proportion of participants reported at least occasionally exceeding speed limits (86.7% of novices), and risky behaviours like driving when tired (83.6% of novices). Substance-impaired driving was associated with avoiding Police, speeding, risky driving intentions, and self-reported crashes and offences. Forty-three percent of respondents who drove after taking drugs also reported alcohol-impaired driving.

DISCUSSION AND CONCLUSIONS

Behaviours of concern include drink driving, speeding, novice driving errors such as misjudging the speed of oncoming vehicles, violations of graduated driver licensing passenger restrictions, driving tired, driving faster if in a bad mood, and active punishment avoidance. Given the interrelationships between the risky driving behaviours, a deeper understanding of influential factors is required to inform targeted and general countermeasure implementation and evaluation during this critical driving period. Notwithstanding this, a combination of enforcement, education, and engineering efforts appear necessary to improve the road safety of the young novice driver, and for the drink-driving young novice driver in particular.

School start times for adolescents

The American Academy of Pediatrics recognizes insufficient sleep in adolescents as an important public health issue that significantly affects the health and safety, as well as the academic success, of our nation's middle and high school students. Although a number of factors, including biological changes in sleep associated with puberty, lifestyle choices, and academic demands, negatively affect middle and high school students' ability to obtain sufficient sleep, the evidence strongly implicates earlier school start times (ie, before 8:30 am) as a key modifiable contributor to insufficient sleep, as well as circadian rhythm disruption, in this population. Furthermore, a substantial body of research has now demonstrated that delaying school start times is an effective countermeasure to chronic sleep loss and has a wide range of potential benefits to students with regard to physical and mental health, safety, and academic achievement. The American Academy of Pediatrics strongly supports the efforts of school districts to optimize sleep in students and urges high schools and middle schools to aim for start times that allow students the opportunity to achieve optimal levels of sleep (8.5-9.5 hours) and to improve physical (eg, reduced obesity risk) and mental (eg, lower rates of depression) health, safety (eg, drowsy driving crashes), academic performance, and quality of life.

Adolescence, attention allocation, and driving safety

Motor vehicle crashes are the leading source of morbidity and mortality in adolescents in the United States and the developed world. Inadequate allocation of attention to the driving task and to driving hazards are important sources of adolescent crashes. We review major explanations for these attention failures with particular focus on the roles that brain immaturity and lack of driving experience play in causing attention problems. The review suggests that the potential for overcoming inexperience and immaturity with training to improve attention to both the driving task and hazards is substantial. Nevertheless, there are large individual differences in both attentional abilities and risky driving tendencies that pose challenges to novice driver policies. Research that can provide evidence-based direction for such policies is urgently needed.

Young novice driver subtypes: relationship to driving violations, errors and lapses

The present study aimed to identify, in a large Italian sample of young, novice drivers, specific subtypes of drivers on the basis of combinations of self-reported personality traits (i.e., driving anger, anxiety, angry hostility, excitement-seeking, altruism, normlessness and driving locus of control) and to evaluate their high-risk driving behaviors not only in terms of traffic rule violations and risk-taking behaviors, but also in terms of driving errors and lapses as measured by the Manchester Driver Behavior Questionnaire. Participants were 1008 high school students between the ages of 18 and 23 years, with valid driver's licenses. On the basis of a cluster analysis of the personality variables, three easily interpretable driver subgroups were identified (risky drivers, worried drivers and careful drivers) that differed on self-reported accident involvement, attitudes toward traffic safety and risk perception, as well as on driving violations, errors, and lapses. The inclusion of internal and external driving locus of control, variables not previously considered in similar cluster studies, provided a relevant contribution to the final cluster solution. Further, the use of the Driving Behavior Questionnaire permitted the differentiation between deliberate deviations from safe driving practices and mistakes due to misjudgments or lapses in attention. This distinction was critical for understanding the behavior of each of the three identified subgroups of drivers, and for planning interventions to promote safe driving.

The use of conspicuity aids by cyclists and risk of crashes involving other road users: a protocol for a population based case-control study

Background

Regular cycling has been shown to improve health and has a role in tackling the threats posed by obesity and inactivity. Cycle collisions, particularly those involving motorised vehicles, can lead to significant mortality and morbidity and are currently a barrier to wider uptake of cycling. There is evidence that the conspicuity of cyclists is a factor in many injury collisions. Low-cost, easy to use retro-reflective and fluorescent clothing and accessories ('conspicuity aids') are available. Their effectiveness in reducing cycling collisions is unknown. The study is designed to investigate the relationship between the use of conspicuity aids and risk of collision or evasion crashes for utility and commuter cyclists in the UK.

Methods/Design

A matched case-control study is proposed. Cases are adult commuter and utility cyclists involved in a crash resulting from a collision or attempted evasion of a collision with another road user recruited at a UK emergency department. Controls are commuter and utility cyclists matched by journey purpose, time and day of travel and geographical area recruited at public and private cycle parking sites. Data on the use of conspicuity aids, crash circumstances, demographics, cycling experience, safety equipment use, journey characteristics and route will be collected using self-completed questionnaires and maps. Conditional logistic regression will be used to calculate adjusted odds ratios and 95% confidence intervals of the risk of a crash when using any item of fluorescent or reflective clothing or equipment.

Discussion

This study will provide information on the effectiveness of conspicuity aids in reducing the risk of injury to cyclists resulting from crashes involving other road users.

Adolescent and young adult crash risk: sensation seeking, substance use propensity and substance use behaviors

In a national youth sample, the propensity to use substances was more strongly related to motor vehicle crashes than use of any specific substance studied (cigarette, alcohol, marijuana). Substance use propensity was associated with sensation seeking, suggesting that increased crash risk for these youth is likely a result of general risk-taking tendencies.