Human factors in the causation of road traffic crashes

Impact of distracted driving on safety and traffic flow

Studies have documented a link between distracted driving and diminished safety; however, an association between distracted driving and traffic congestion has not been investigated in depth. The present study examined the behavior of teens and young adults operating a driving simulator while engaged in various distractions (i.e., cell phone, texting, and undistracted) and driving conditions (i.e., free flow, stable flow, and oversaturation). Seventy five participants 16-25 years of age (split into 2 groups: novice drivers and young adults) drove a STISIM simulator three times, each time with one of three randomly presented distractions. Each drive was designed to represent daytime scenery on a 4 lane divided roadway and included three equal roadway portions representing Levels of Service (LOS) A, C, and E as defined in the 2000 Highway Capacity Manual. Participants also completed questionnaires documenting demographics and driving history. Both safety and traffic flow related driving outcomes were considered. A Repeated Measures Multivariate Analysis of Variance was employed to analyze continuous outcome variables and a Generalized Estimate Equation (GEE) Poisson model was used to analyze count variables. Results revealed that, in general more lane deviations and crashes occurred during texting. Distraction (in most cases, text messaging) had a significantly negative impact on traffic flow, such that participants exhibited greater fluctuation in speed, changed lanes significantly fewer times, and took longer to complete the scenario. In turn, more simulated vehicles passed the participant drivers while they were texting or talking on a cell phone than while undistracted. The results indicate that distracted driving, particularly texting, may lead to reduced safety and traffic flow, thus having a negative impact on traffic operations. No significant differences were detected between age groups, suggesting that all drivers, regardless of age, may drive in a manner that impacts safety and traffic flow negatively when distracted.

Acidentes entre motocicletas: análise dos casos ocorridos no estado do Paraná entre julho de 2010 e junho de 2011

Acidentes que ocorrem entre duas motocicletas têm sido esquecidos na imensidão dos acidentes de trânsito no Brasil, carecendo de serem melhor analisados. Este estudo buscou analisar epidemiologicamente os acidentes que ocorrem entre duas motocicletas, comparando com os outros tipos, a partir de dados do estado do Paraná. Foram capturadas informações do sítio eletrônico da Corporação de Bombeiros relativas ao período de um ano (julho/2010 a junho/2011), sobre o número e tipo de acidente, dia da semana, período do dia, número de vítimas, gênero, idade e gravidade das lesões. Ocorrências moto x moto representaram 3,4% do total de acidentes de trânsito registrados e 6,2% dos acidentes envolvendo motocicleta; as vítimas deste tipo de acidente corresponderam, respectivamente, a 4,4% do total de vitimados e a 8,5% daquelas em acidentes com motocicleta. Acidentes ocorridos aos sábado, sexo masculino e idade entre 20 a 29 anos foram mais frequentes neste tipo de eventos. Dentre as dez cidades mais populosas do estado, algumas se destacaram pelo alto índice destes acidentes, que parece guardar relação com o índice de motorização de motos das localidades. Assim, torna-se fundamental a constante avaliação destes índices e a implantação de medidas que visem proporcionar um trânsito mais seguro.

Risk factors for causing road crashes involving cyclists: An application of a quasi-induced exposure method

A quasi-induced exposure approach was applied to the Spanish Register of Traffic Crashes to identify driver- and vehicle-related factors associated with the risk of causing a road crash involving a cyclist in Spain from 1993 to 2009. We analyzed 19,007 collisions between a bicycle and another vehicle in which only one of the drivers committed an infraction, and 13,540 records that included the group of non-infractor cyclists in the above collisions plus cyclists involved in single-bicycle crashes. Adjusted odds ratios were calculated for being responsible for each type of crash for each factor considered. Age from 10 to 19 years, male sex, alcohol or drug consumption and non-helmet use were cyclist-related variables associated with a higher risk of crash, whereas cycling more than 1h increased only the risk of single crashes. Bicycles with brake defects and ridden by two occupants were also at higher risk of involvement in a crash, whereas light defects were associated only with collisions with another vehicle. For drivers of the other vehicle, age more than 60 years, alcohol, not using safety devices and nonprofessional drivers were at higher risk. The risk of colliding with a bicycle was higher for mopeds than for passenger cars.

A spatial generalized ordered response model to examine highway crash injury severity

This paper proposes a flexible econometric structure for injury severity analysis at the level of individual crashes that recognizes the ordinal nature of injury severity categories, allows unobserved heterogeneity in the effects of contributing factors, as well as accommodates spatial dependencies in the injury severity levels experienced in crashes that occur close to one another in space. The modeling framework is applied to analyze the injury severity sustained in crashes occurring on highway road segments in Austin, Texas. The sample is drawn from the Texas Department of Transportation (TxDOT) crash incident files from 2009 and includes a variety of crash characteristics, highway design attributes, driver and vehicle characteristics, and environmental factors. The results from our analysis underscore the value of our proposed model for data fit purposes as well as to accurately estimate variable effects. The most important determinants of injury severity on highways, according to our results, are (1) whether any vehicle occupant is ejected, (2) whether collision type is head-on, (3) whether any vehicle involved in the crash overturned, (4) whether any vehicle occupant is unrestrained by a seat-belt, and (5) whether a commercial truck is involved.

Road traffic safety beliefs and driver behaviors among personality subtypes of drivers in the Norwegian population

OBJECTIVE

To identify personality clusters of drivers in a population-based sample and to examine differences in safety beliefs, driver behaviors, and demographics between these clusters.

METHODS

A mailed self-completion questionnaire survey was conducted in a random sample of Norwegian drivers obtained from the Norwegian Population Registry (n = 1731).

RESULTS

Cluster analysis reflected 4 personality subtypes of drivers. The first cluster consisted of drivers with low normlessness and sensation seeking but high anxiety. The second cluster reported elevated scores on all 3 measured traits, whereas the third cluster had low scores on all traits. The fourth cluster reported low anxiety but high normlessness and sensation seeking. People in the latter cluster reported unsafe road traffic safety beliefs and driver behaviors. These individuals were also more likely to be males and adolescents. People with low normlessness and sensation seeking coupled with high anxiety reported the safest beliefs and behaviors, and this cluster mainly contained females and older individuals.

CONCLUSIONS

Countermeasures aimed to reduce the frequency of road traffic accidents should be targeted to specific personality risk groups. Personality traits may also be used in early identification and intervention among risky drivers.

Police documentation of alcohol involvement in hospitalized injured drivers

OBJECTIVE

Injured drivers with blood alcohol concentration (BAC) above the legal limit are rarely convicted of impaired driving. One explanation is that police may have difficulty recognizing alcohol intoxication in injured drivers. In this study, we compare police documentation of alcohol involvement with BAC measured on arrival at a hospital. Our objectives were to determine how often police document alcohol involvement in injured drivers with BAC ≥ 0.05 percent and identify factors that influence police documentation of alcohol involvement.

METHODS

We included injured drivers (1999-2003) who were admitted to a British Columbia trauma center or treated in the Vancouver General Hospital emergency department. We used probabilistic linkage to obtain police collision reports. Police were considered to have indicated alcohol involvement if (1) police documented that alcohol contributed to the crash, (2) the driver received an administrative sanction for impaired driving, or (3) the driver was criminally convicted of impaired driving. The proportion of drivers for whom police indicated alcohol involvement was determined relative to age, gender, BAC levels, crash severity, and crash characteristics. Multivariate logistic regression was used to identify factors independently associated with police indication of alcohol involvement.

RESULTS

Two thousand four hundred and ten injured drivers (73.5% male) were matched to a police report. Overall, 857 (35.6%) drivers tested positive for alcohol (BAC ≥ 0) and 736/857 (85.9%) of alcohol-positive drivers had a BAC ≥ 0.05 percent (the legal limit in British Columbia). Of the 736 drivers with a BAC > 0.05 percent at time of admission, police indicated alcohol involvement in 530 (72.0%). The criminal code conviction rate for impaired driving was 4.7 percent for drivers with 0.08 percent ≤ BAC < 0.16 percent and 13.6 percent for drivers with BAC > 0.16 percent. The following factors were associated with higher odds of police indicating alcohol involvement: (1) increasing blood alcohol levels, (2) a prior record of impaired driving, (3) involvement in a single-vehicle crash, (4) involvement in a nighttime crash, and (5) traffic violations or unsafe driving actions recorded by police.

CONCLUSIONS

Police recognized and documented alcohol involvement in 72 percent of injured drivers with BAC ≥ 0.05 percent. Police documentation of alcohol involvement was more common at higher BAC levels, in nighttime or single-vehicle crashes, for drivers who committed traffic violations or drove unsafely, and for drivers with a prior record of impaired driving. The low conviction rate of injured impaired drivers does not appear to be due to police inability to recognize alcohol involvement.

Association between cannabis use and non-traffic injuries

BACKGROUND

This study aimed to assess the association between cannabis use and unintended non-fatal injuries other than those caused by road crashes.

METHODS

Cross-sectional data were collected from a nationwide sample of 27,934 subjects surveyed in 2005 in Spain: 14,699 persons aged 15-34 years and 13,235 aged 35-64 years. Logistic regression was used to obtain odds ratios (OR) between patterns of cannabis use and frequency of non-traffic injuries, adjusted for sociodemographic factors and for the use of alcohol, tobacco and other drugs.

RESULTS

Cannabis use in the last 12 months was associated with a higher frequency of injuries (OR=1.4; 95% CI: 1.2-1.7). The OR in older adults (35-64 year age group) was 1.8 and 1.3 in younger people (15-34 year age group). The strongest associations found were between weekly use of cannabis and injuries from knocks and bumps (OR=5.1; 95% CI 2.9-8.9) and those occurring outside work (OR=3.0; 95% CI 1.8-4.9) in the older adult population.

CONCLUSION

Although our analysis did not control for behavioural factors, cannabis use is independently associated with an increased frequency of non-traffic injuries, especially in the older adult population. These associations emphasise the need to carry out longitudinal studies addressing the causal links between cannabis use and unintended injuries.

Impaired knowledge of driving laws is associated with recommended driving cessation in cognitively impaired older adults

Background/Aims

The present study examined if knowledge of driving laws independently predicts on-the-road driving performance among cognitively impaired older adults.

Methods

The current study consisted of retrospective observational analyses on 55 cognitively impaired older adults (77.9 ± 6.4 years) that completed an on-the-road driving evaluation, a 20-item knowledge test of driving laws, and a brief cognitive test battery.

Results

Logistic regression found poorer performance on the knowledge test was significantly associated with greater likelihood of recommended driving cessation beyond important demographic and cognitive variables (p < 0.05).

Conclusion

Cognitively impaired patients’ ability to drive may be related to their knowledge regarding common driving laws, in addition to their current level of cognitive functioning.

Roadway crash risks in recent immigrants

Adult immigrants are sometimes characterized as unsafe drivers and responsible for excess road crashes. We analyzed Canada's largest and most ethnically diverse province to assess whether recent immigrants had an increased risk of involvement as drivers in serious motor vehicle crashes. Overall, the study included 4,238,222 individuals followed for a median duration of 8.0 years. In total, 10,975 individuals were subsequently admitted to hospital as drivers involved in a crash, with a rate per 100,000 significantly lower among recent immigrants compared to long-term residents (158 vs 289, p<0.001). This difference was equal to a 45% relative reduction in the incidence of a crash (odds ratio=0.55, 95% confidence interval 0.52-0.58), persisted after adjustment for baseline characteristics (hazard ratio=0.61, 95% confidence interval 0.58-0.65), extended to extremes of crash severity, and was accentuated during initial years following immigration. These findings suggest that, contrary to popular opinion, recent immigrants are less prone to be drivers in serious motor vehicle crashes.

Psychoactive substance use and the risk of motor vehicle crash injuries in southern Taiwan

The purpose of this study was to examine the association between psychoactive drug use and motor vehicle crash (MVC) injuries requiring hospitalization in southern Taiwan. A case-control study was conducted in southern Taiwan from January 2009 to December 2009. The cases included car or van drivers who were involved in MVCs and required hospitalization. Demographic and trauma-related data were collected from questionnaires and hospital and ambulance records. Urine and/or blood samples were collected on admission. The controls consisted of drivers who were randomly recruited while driving on public roads. Study subjects were interviewed and asked to provide urine samples. All blood and urine samples were tested for alcohol and a number of other legal and illegal drugs. Only those subjects who provided urine and/or blood specimens were included in the study. During the study period, 254 case patients and 254 control drivers were enrolled. The analysis showed an odds ratio (OR) of 3.41 (95% confidence intervals (95% CI), 1.76-6.70; p < 0.001) for persons taking benzodiazepines, and an OR of 3.50 (95% CI, 1.81-6.85; p < 0.001) for those taking alcohol (blood alcohol concentrations (BAC) ≥ 0.8 g/l) with regard to hospitalizations due to MVCs. For persons taking combinations of benzodiazepines and alcohol, the OR increased to 5.12 (95% CI: 1.77-15.91, p < 0.001). This study concluded that drug use among motor vehicle drivers increases the risk of MVCs that require hospitalization. From a public health perspective, the high risk ratios are concerning, and preventive measures are warranted.

An integrated surveillance system of road traffic injuries in the Lazio region of Italy: results of a 5-year study (2001-2005)

Road traffic injuries represent a relevant public-health problem. In the Lazio region of Italy, a surveillance system was activated. The aim of this work is to describe the surveillance system and report the health information in terms of temporal trends for the 5-year period 2001-2005. We identified all emergency department (ED) visits in the emergency database and then linked them with hospital discharges and mortality registry. From the integrated database, we calculated the rates of emergency room visits, of hospital admissions, and of mortality, reporting the temporal trends. Between 2001 and 2005 the rate of ED visits was 3151 per 100,000 inhabitants. Hospitalisation rates showed a significant decreasing trend. The surveillance identified 22% more deaths in the study period than reported by the official statistics. The surveillance revealed a decreasing trend for hospital admissions and a decline in deaths in 2003 concurrent to the introduction of the driver's licence point system.

Manipulation specific effects of mental fatigue: evidence from novelty processing and simulated driving

Mental fatigue has a wide range of effects on cognitive, behavioral, and motivational measures. It can be expected that specific effects in which fatigue becomes manifest is dependent on the nature of fatigue-inducing activity (e.g., level of control and working memory demands). This study examined how fatigue caused by tasks that differ on the level of working memory demands (0-Back, 2-Back) affects brain function (novelty processing, P3a) and performance (driving). Results showed that fatigue did not affect driving performance. Fatigue did reduce P3a amplitude, but only after 2-Back. P3a was also reduced during driving. The effects of fatigue and driving on P3a were additive. In summary, both driving and fatigue reduced P3a amplitude. Driving effects were always present. Fatigue effects on novelty processing were dependent on the cognitive demands of the fatigue-inducing task.

Traffic rule violations of private bus drivers and bus crashes in Sri Lanka: a case-control study

OBJECTIVE

To explore the association between self-reported traffic rule violations of private sector bus drivers and bus crashes in the Kandy district, Sri Lanka.

METHODS

We carried out a case-control study from August to September 2006. Cases were all the private bus drivers registered in the Kandy district and involved in crashes reported to the police between November 2005 and April 2006 (n = 63). We included two control groups: the private bus drivers working on the same routes of the cases (n = 90; matched controls) and the drivers selected randomly from the other routes of the district (n = 111; unmatched controls). We used a self-administered questionnaire to collect data on the self-reported traffic rule violations and analyzed the association between the self-reported traffic rule violations and crashes using logistic regression.

RESULTS

The following variables showed significant associations with private bus crashes: illegal overtaking (matched controls, adjusted odds ratio [AOR] = 14.78, unmatched controls, AOR = 1.04), taking passengers outside the bus bays (matched controls, AOR = 3.96, unmatched controls, AOR = 2.29), and overloading (matched controls, AOR = 10.26, unmatched controls, AOR = 1.93). However, we did not observe an association between high-speed driving and bus crashes matched controls, AOR = 1.22, unmatched controls, AOR = 0.81.

CONCLUSIONS

Traffic rule violations, such as illegal overtaking, overloading, and taking passengers outside the bus bays, are significant risk factors for private bus crashes in Sri Lanka.

Data acquisition, analysis and transmission platform for a Pay-As-You-Drive system

This paper presents a platform used to acquire, analyse and transmit data from a vehicle to a Control Centre as part of a Pay-As-You-Drive system. The aim is to monitor vehicle usage (how much, when, where and how) and, based on this information, assess the associated risk and set an appropriate insurance premium. To determine vehicle usage, the system analyses the driver’s respect for speed limits, driving style (aggressive or non-aggressive), mobile telephone use and the number of vehicle passengers. An electronic system on board the vehicle acquires these data, processes them and transmits them by mobile telephone (GPRS/UMTS) to a Control Centre, at which the insurance company assesses the risk associated with vehicles monitored by the system. The system provides insurance companies and their customers with an enhanced service and could potentially increase responsible driving habits and reduce the number of road accidents.

Identifying at-risk older adult community-dwelling drivers through neuropsychological evaluation

This study examined the predictive validity of widely utilized neuropsychological tests, the Cognitive Behavioral Driving Inventory (CBDI) and the Useful Field of View (UFOV), to predict driving abilities in a community-dwelling older adult population. Thirty-nine older adults were given the test battery and an on-the-road driving test. Results indicated that while performance on both the CBDI and UFOV was significantly predictive of driving performance, neuropsychological tests of executive function, memory, and visual perception were more predictive of on-the-road driving ability. These results suggest that standard neuropsychological assessment may be able to identify mild cognitive impairment as it relates to at-risk driving in a community-dwelling older adult population.

Perceived Self-Efficacy and Risky Driving Behaviors

Les recherches dans le domaine de la santé, et notamment en matière de conduite automobile, attestent que le jugement subjectif du risque (comparatif et absolu) et l’auto-efficacité perçue sont impliqués dans les comportements à risque. Cette étude avait pour objectif d’étudier l’influence de l’auto-efficacité perçue sur le jugement subjectif du risque, évalué au moyen d’une mesure indirecte, et de tester le rôle médiateur de ce facteur entre l’auto-efficacité perçue et les comportements auto-déclarés. Les participants, 90 hommes, lisaient deux scénarii décrivant les deux comportements les plus impliqués dans l’accidentologie: la vitesse et l’alcool au volant. Les résultats ne montrent pas de lien significatif entre l’auto-efficacité perçue et le score de jugement comparatif mais une relation significative avec les deux évaluations absolues du risque (autrui et soi). De plus, le jugement absolu du risque pour soi médiatise partiellement la relation entre auto-efficacité perçue et comportements auto-déclarés relatifs aux deux risques routiers étudiés.

Saving lives in road traffic-ethical aspects

Aim

This article aims at giving an overview of five ethical problem areas relating to traffic safety, thereby providing a general framework for analysing traffic safety from an ethical perspective and encouraging further discussion concerning problems, policies and technology in this area.

Subjects and methods

The problems presented in the article are criminalisation, paternalism, privacy, justice and responsibility, and the reasons for choosing these are the following. First, they are all important areas in moral philosophy. Second, they are fairly general and it should be possible to categorise more specific problems under these headings. Ethical aspects of road traffic have not received the philosophical attention they deserve. Every year, more than 1 million people die globally in traffic accidents, and 20 to 50 million people are injured. Ninety per cent of the road traffic fatalities occur in low- and middle-income countries, where it is a growing problem. Politics, economics, culture and technology affect the number of fatalities and injuries, and the measures used to combat deaths in traffic as well as the role of road traffic should be ethically scrutinised. The topics are analysed and discussed from a moral-philosophical perspective, and the discussion includes both theory and applications.

Results and conclusion

The author concludes with some thoughts on how the ethical discussion can be included in the public debate on how to save lives in road traffic. People in industrialised societies are so used to road traffic that it is almost seen as part of nature. Consequently, we do not acknowledge that we can introduce change and that we can affect the role we have given road traffic and cars. By acknowledging the ethical aspects of road traffic and illuminating the way the choices society makes are ethically charged, it becomes clear that there are alternative ways to design the road traffic system. The most important general conclusion is that discussion concerning these alternative ways of designing the system should be encouraged.

[Evidence-based effectiveness of road safety interventions: a literature review]

INTRODUCTION

Only road safety interventions with scientific evidence supporting their effectiveness should be implemented. The objective of this study was to identify and summarize the available evidence on the effectiveness of road safety interventions in reducing road traffic collisions, injuries and deaths.

METHODOLOGY

All literature reviews published in scientific journals that assessed the effectiveness of one or more road safety interventions and whose outcome measure was road traffic crashes, injuries or fatalities were included. An exhaustive search was performed in scientific literature databases. The interventions were classified according to the evidence of their effectiveness in reducing road traffic injuries (effective interventions, insufficient evidence of effectiveness, ineffective interventions) following the structure of the Haddon matrix.

RESULTS

Fifty-four reviews were included. Effective interventions were found before, during and after the collision, and across all factors: a) the individual: the graduated licensing system (31% road traffic injury reduction); b) the vehicle: electronic stability control system (2 to 41% reduction); c) the infrastructure: area-wide traffic calming (0 to 20%), and d) the social environment: speed cameras (7 to 30%). Certain road safety interventions are ineffective, mostly road safety education, and others require further investigation.

CONCLUSION

The most successful interventions are those that reduce or eliminate the hazard and do not depend on changes in road users' behavior or on their knowledge of road safety issues. Interventions based exclusively on education are ineffective in reducing road traffic injuries.

Increased incidence of traffic accidents in Toxoplasma-infected military drivers and protective effect RhD molecule revealed by a large-scale prospective cohort study

Background

Latent toxoplasmosis, protozoan parasitosis with prevalence rates from 20 to 60% in most populations, is known to impair reaction times in infected subjects, which results, for example, in a higher risk of traffic accidents in subjects with this life-long infection. Two recent studies have reported that RhD-positive subjects, especially RhD heterozygotes, are protected against latent toxoplasmosis-induced impairment of reaction times. In the present study we searched for increased incidence of traffic accidents and for protective effect of RhD positivity in 3890 military drivers.

Methods

Male draftees who attended the Central Military Hospital in Prague for regular entrance psychological examinations between 2000 and 2003 were tested for Toxoplasma infection and RhD phenotype at the beginning of their 1 to1.5-year compulsory military service. Subsequently, the data on Toxoplasma infection and RhD phenotype were matched with those on traffic accidents from military police records and the effects of RhD phenotype and Toxoplasma infection on probability of traffic accident was estimated with logistic regression.

Results

We confirmed, using for the first time a prospective cohort study design, increased risk of traffic accidents in Toxoplasma-infected subjects and demonstrated a strong protective effect of RhD positivity against the risk of traffic accidents posed by latent toxoplasmosis. Our results show that RhD-negative subjects with high titers of anti-Toxoplasma antibodies had a probability of a traffic accident of about 16.7%, i.e. a more than six times higher rate than Toxoplasma-free or RhD-positive subjects.

Conclusion

Our results showed that a common infection by Toxoplasma gondii could have strong impact on the probability of traffic accident in RhD negative subjects. The observed effects could provide not only a clue to the long-standing evolutionary enigma of the origin of RhD polymorphism in humans (the effect of balancing selection), but might also be the missing piece in the puzzle of the physiological function of the RhD molecule.

Alcohol and drugs in fatally and non-fatally injured motor vehicle drivers in northern Sweden

Alcohol and drugs are important risk factors for traffic injuries, a major health problem worldwide. This prospective study investigated the epidemiology and the presence of alcohol and drugs in fatally and hospitalized non-fatally injured drivers of motor vehicles in northern Sweden. During a 2-year study period, blood from fatally and hospitalized non-fatally injured drivers was tested for alcohol and drugs. The study subjects were recruited from well-defined geographical areas with known demographics. Autopsy reports, medical journals, police reports, and toxicological analyses were evaluated. Of the fatally injured, 38% tested positive for alcohol and of the non-fatally 21% tested positive; 7% and 13%, respectively, tested positive for pharmaceuticals with a warning for impaired driving; 9% and 4%, respectively, tested positive for illicit drugs. The most frequently detected pharmaceuticals were benzodiazepines, opiates, and antidepressants. Tetrahydrocannabinol was the most frequently detected illicit substance. No fatally injured women had illegal blood alcohol concentration. The relative proportion of positively tested drivers has increased and was higher than in a similar study 14 years earlier. This finding indicates that alcohol and drugs merit more attention in future traffic safety work.

Teen driver crash risk and associations with smoking and drowsy driving

Motor vehicle crashes are the leading cause of death for young people in the United States. The goal of this study was to identify risk factor profiles of teen and young adult drivers involved in crashes. General demographic and behavioral as well as driving-related factors were considered. Analysis of a nationally representative telephone survey of U.S. young drivers ages 14 to 22 (N=900) conducted in 2005 was restricted to 506 licensed drivers (learners excluded). Statistically significant univariate associations between factors of interest and the primary outcome, crash involvement (ever) as a driver, were identified and included within a multivariate logistic regression model, controlling for potential demographic confounders. Aside from length of licensure, only driving alone while drowsy and being a current smoker were associated with having been in a crash. Gaining a better understanding of these behaviors could enhance the development of more customized interventions for new drivers.

The joint association of average volume of alcohol and binge drinking with hazardous driving behaviour and traffic crashes

BACKGROUND

Previous studies on alcohol-related road safety have not assessed the joint impact of average volume of alcohol and binge drinking.

AIM

To examine the joint and separate association of average volume of alcohol and binge drinking with hazardous driving behaviour and traffic crashes.

METHODS

Data were drawn from telephone interviews conducted in the period 2000-2005, with 12 037 individuals representative of the population aged 18-64 years in the Madrid region, Spain. The threshold between average moderate and heavy volumes was 40 g of alcohol/day in men and 24 g/day in women. Binge drinking was defined as intake of >or= 80 g of alcohol in men and >or= 60 g in women, during any drinking occasion in the preceding 30 days. Individuals were classified into the following categories: (i) non-drinkers; (ii) moderate drinkers with no binge drinking (MDNB); (iii) moderate drinkers with binge drinking (MDB); (iv) heavy drinkers with no binge drinking (HDNB); and (v) heavy drinkers with binge drinking (HDB). Analyses were performed using logistic regression, with adjustment for sex, age and educational level.

FINDINGS

Frequency of inadequate seat-belt use increased progressively across categories of alcohol consumption, with odds ratio (OR) 1 in non-drinkers, 1.19 [95% confidence interval (CI) 1.06-1.33] in MDNB, 1.69 (1.41-2.03) in MDB, 1.68 (1.24-2.29) in HDNB and 2.41 (1.83-3.18) in HDB (P for trend <0.001). Compared with MDNB, alcohol-impaired driving was also more frequent in MDB (OR 7.43; 95% CI: 5.52-10.00), HDNB (OR 7.31; 95% CI: 4.37-12.25) and in HDB (OR 15.50; 95% CI: 10.62-22.61). Lastly, compared with non-drinkers, frequency of traffic crashes increased progressively across categories of alcohol consumption (P for trend=0.028), although it only reached statistical significance in HDB (OR 2.01; 95% CI: 1.00-4.09).

CONCLUSIONS

Self-reported average volume of alcohol and binge drinking are both associated with self-reported hazardous driving behaviour and traffic crashes. The strength of the association is greater when average heavy consumption and binge drinking occur jointly.

Drinking, drugs and driving in Ireland: more evidence for action

OBJECTIVE

To examine the prevalence of drug positivity among drivers suspected of driving under the influence of an intoxicant, and consequently apprehended by the police in Ireland.

DESIGN

2000 specimens were selected for drug analysis, 1000 with results under the limit for alcohol and 1000 over the limit. The limit for alcohol is 80 mg/100 ml in blood and 107 mg/100 ml in urine. Seven drugs/drug classes were examined; amphetamines, methamphetamines, benzodiazapines, cannabinoids, cocaine, opiates and methadone.

RESULTS

331 (33.1%) of the drivers under the legal limit for alcohol tested positive for one or more of the relevant drugs, and the corresponding figures of drivers over the limit was 142 (14.2%; p<0.001). Using weighted analysis, this corresponds to 15.7% (95% confidence interval (CI) 13.5% to 18.1%) of all tested drivers (15.8% in men and 14.5% in women). Among drivers who had minimal blood alcohol levels, 67.9% (95% CI 61.2% to 74.1%) were taking at least one type of drug. The prevalence of taking drugs reduced steadily as alcohol concentrations increased, but still remained as high as 11.1% (95% CI 8.3% to 14.6%) for drivers with blood alcohol concentrations >200 mg/100 ml. Being under the limit for alcohol, stopped in a city area, stopped between 6 am and 4 pm, or 4 pm and 9 pm, and being of a younger age were each independently associated with drug positivity.

CONCLUSIONS

There are immediate implications for the evidential breath alcohol program and for checkpoints; in the event of a nil or low alcohol reading being obtained, a separate blood or urine specimen should be sought for analysis, which is currently non-routine.

A joint econometric analysis of seat belt use and crash-related injury severity

This paper formulates a comprehensive econometric structure that recognizes two important issues in crash-related injury severity analysis. First, the impact of a factor on injury severity may be moderated by various observed and unobserved variables specific to an individual or to a crash. Second, seat belt use is likely to be endogenous to injury severity. That is, it is possible that intrinsically unsafe drivers do not wear seat belts and are the ones likely to be involved in high injury severity crashes because of their unsafe driving habits. The preceding issues are considered in the current research effort through the development of a comprehensive model of seat belt use and injury severity that takes the form of a joint correlated random coefficients binary-ordered response system. To our knowledge, this is the first instance of such a model formulation and application not only in the safety analysis literature, but in the econometrics literature in general. The empirical analysis is based on the 2003 General Estimates System (GES) data base. Several types of variables are considered to explain seat belt use and injury severity levels, including driver characteristics, vehicle characteristics, roadway design attributes, environmental factors, and crash characteristics. The results, in addition to confirming the effects of various explanatory variables, also highlight the importance of (a) considering the moderating effects of unobserved individual/crash-related factors on the determinants of injury severity and (b) seat belt use endogeneity. From a policy standpoint, the results suggest that seat belt non-users, when apprehended in the act, should perhaps be subjected to both a fine (to increase the chances that they wear seat belts) as well as mandatory enrollment in a defensive driving course (to attempt to change their aggressive driving behaviors).

Minimal hepatic encephalopathy: a vehicle for accidents and traffic violations

OBJECTIVES

MHE patients have impairment on driving tests. However, it is unclear whether this impairment is restricted to the testing environment or is associated with increased traffic violations and/or motor vehicle accidents.

METHODS

An anonymous driving history and driving behavior questionnaire (DBQ: self-scored, best score 104), coded according to MHE status, was sent to 200 cirrhotics without overt hepatic encephalopathy and 100 age/education-matched controls. The questionnaire inquired about demographics, alcohol/illegal drug use, and violations/accidents within 1 and 5 yr. The cirrhotics had been divided into those with MHE (MHE+), without MHE (MHE-), and those not tested for MHE because of psychoactive drug use, on a previous study.

RESULTS

Cirrhotics versus controls had similar driving duration, alcohol/illegal drug use but significantly higher percentage with violations within both 1 and 5 yr (25%vs 4%[5 yr]), 13%vs 2%[(1 yr]), accidents (17%vs 4%[5 yr]), 9%vs 1%[1 yr]), and both (34%vs 7%[5 yr], 18%vs 3%[1 yr]). MHE+ cirrhotics had significantly higher percentage with violations (36%[5 yr], 21%[1 yr]), accidents (33%[5 yr]), 17%[1 yr]), and both (53%[5 yr], 33%[1 yr]) versus other cirrhotics. DBQ score was significantly lower in cirrhotics than controls (92 vs 99). Within cirrhotics, DBQ score was highest in MHE-versus other groups. MHE+ status was the only risk factor (odds ratios: 4.2-7.6) for violations and for accidents on multivariate logistic regression.

CONCLUSIONS

Cirrhotics have a higher self-reported occurrence of violations and accidents compared to controls. MHE+ a is strong predictor for violations and accidents. Prospective studies investigating the effect of MHE treatment on violations and accidents are warranted.

Patterns of injuries and motor-vehicle traffic accidents in Athens

The extremely high cost of motor-vehicle accidents in public health leads to the necessity of a better injury data collection in the Accident and Emergency Hospital Departments. The 'Asclepeion' of Voula Hospital covers the southeastern suburban areas of the greater Athens area (1,000,000 population). The aim of this study is to present information on the pattern of injuries in Athens, in order to understand the magnitude of the problem and develop rational prevention programmes. Specially trained health visitors of the Emergency Department Injury Surveillance System (EDISS) interviewed in person every injured victim who was brought into the Emergency Service of the 'Asclepeion' of Voula Hospital. The study was performed during a 3-year period, from 1996 to 1998; 4564 persons were interviewed. Traffic accidents were more frequent on weekdays with a seasonal peak in July and among young Greeks (aged 25 - 34 years). The usual type of injuries seen in vehicle-accident victims were cerebral contusion and concussion, while in motorcycle-accident victims, head contusion and fractures. The most common reasons for the accident were excessive speed, poor condition of road, inattention, abstraction or drowsiness and drug effects. A total of 29.8% of motorcycle drivers and 5.7% of motorcycle passengers wore a helmet and 26.3% of car drivers and 14.1% of car passengers were using seatbelts. The identification of road traffic injury patterns can contribute to the development of injury prevention measures and guide rational preventive interventions that can reduce the incidence of these injuries. The EDISS system established at 'Asclepeion' of Voula Emergency Service can provide useful and accurate information about this serious and multidimensional problem of Greek Public Health.

Comparison between two quasi-induced exposure methods for studying risk factors for road crashes

This study was designed to compare estimates from two quasi-induced exposure methods of the effects of driver- and vehicle-related conditions on the risk of causing a road crash for drivers of vehicles with four or more wheels. From the Spanish register of road crashes with victims, the authors selected, for 1993-2002, all 755,329 drivers of >or=4-wheeled vehicles involved in single-vehicle crashes or in two-vehicle collisions in which only one of the drivers was considered responsible. Multinomial and logistic regression models were used to obtain the odds ratio for each driver- and vehicle-related variable. Construction of these models was based on the assumptions of classical quasi-induced exposure methods and on the method (a paired-by-collision analysis of responsible and nonresponsible drivers) proposed by Perneger and Smith (Am J Epidemiol 1991;134:1138-45). The main driver-dependent conditions for any type of crash were psychophysical circumstances (alcohol use and sleepiness). The effect of most driver- and vehicle-related characteristics was higher for single-vehicle crashes than for two-vehicle collisions. Furthermore, both classical and paired-by-collision analyses yielded similar estimates and can be considered equally useful alternatives for assessing the effect of driver and vehicle characteristics on the risk of causing a collision between two vehicles.

Driver dependent factors and the risk of causing a collision for two wheeled motor vehicles

OBJECTIVE

To assess the effect of driver dependent factors on the risk of causing a collision for two wheeled motor vehicles (TWMVs).

DESIGN

Case control study.

SETTING

Spain, from 1993 to 2002.

SUBJECTS

All drivers of TWMVs involved in the 181 551 collisions between two vehicles recorded in the Spanish registry which did not involve pedestrians, and in which at least one of the vehicles was a TWMV and only one driver had committed a driving infraction. The infractor and non-infractor drivers constituted the case and control groups, respectively.

MAIN OUTCOME MEASURES

Logistic regression analyses were used to obtain crude and adjusted odds ratio estimates for each of the driver related factors recorded in the registry (age, sex, nationality, psychophysical factors, and speeding infractions, among others).

RESULTS

Inappropriate speed was the variable with the greatest influence on the risk of causing a collision, followed by excessive speed and driving under the influence of alcohol. Younger and older drivers, foreign drivers, and driving without a valid license were also associated with a higher risk of causing a collision. In contrast, helmet use, female sex, and longer time in possession of a driving license were associated with a lower risk.

CONCLUSIONS

Although the main driver dependent factors related to the risk of causing a collision for a TWMV were similar to those documented for four wheeled vehicles, several differences in the pattern of associations support the need to study moped and motorcycle crashes separately from crashes involving other types of vehicles.

Sleepiness/fatigue and distraction/inattention as factors for fatal versus nonfatal commercial motor vehicle driver injuries

A retrospective population-based case-control study was conducted to determine whether driver sleepiness/fatigue and inattention/distraction increase the likelihood that a commercial motor vehicle collision (CVC) will be fatal. Cases were identified as CVC drivers who died (fatal) and controls were drivers who survived (nonfatal) an injury collision using the Kentucky Collision Report Analysis for Safer Highways (CRASH) electronic database from 1998-2002. Cases and controls were matched on unit type and roadway type. Conditional logistic regression was performed. Driver sleepiness/fatigue, distraction/inattention, age of 51 years of age and older, and nonuse of safety belts increase the odds that a CVC will be fatal. Primary safety belt law enactment and enforcement for all states, commercial vehicle driver education addressing fatigue and distraction and other approaches including decreased hours-of-service, rest breaks and policy changes, etc. may decrease the probability that a CVC will be fatal.

The neural correlates of driving performance identified using positron emission tomography

Driving is a complex behavior involving multiple cognitive domains. To identify neural correlates of driving performance, [15O]H2O positron emission tomography was performed using a simulated driving task. Compared with the resting condition, simulated driving increased regional cerebral blood flow (rCBF) in the cerebellum, occipital, and parietal cortices. Correlations between rCBF and measurements of driving performance were evaluated during simulated driving. Interestingly, rCBF in the thalamus, midbrain, and cerebellum were positively correlated with time required to complete the course and rCBF in the posterior cingulate gyrus was positively correlated with number of crashes during the task. These brain regions may thus play roles in the maintenance of driving performance.

Psychoactive substance use and the risk of motor vehicle accidents

The driving performance is easily impaired as a consequence of the use of alcohol and/or licit and illicit drugs. However, the role of drugs other than alcohol in motor vehicle accidents has not been well established. The objective of this study was to estimate the association between psychoactive drug use and motor vehicle accidents requiring hospitalisation. A prospective observational case-control study was conducted in the Tilburg region of The Netherlands from May 2000 to August 2001. Cases were car or van drivers involved in road crashes needing hospitalisation. Demographic and trauma related data was collected from hospital and ambulance records. Urine and/or blood samples were collected on admission. Controls were drivers recruited at random while driving on public roads. Sampling was conducted by researchers, in close collaboration with the Tilburg police, covering different days of the week and times of the day. Respondents were interviewed and asked for a urine sample. If no urine sample could be collected, a blood sample was requested. All blood and urine samples were tested for alcohol and a number of licit and illicit drugs. The main outcome measures were odds ratios (OR) for injury crash associated with single or multiple use of several drugs by drivers. The risk for road trauma was increased for single use of benzodiazepines (adjusted OR 5.1 (95% Cl: 1.8-14.0)) and alcohol (blood alcohol concentrations of 0.50-0.79 g/l, adjusted OR 5.5 (95% Cl: 1.3-23.2) and >or=0.8 g/l, adjusted OR 15.5 (95% Cl: 7.1-33.9)). High relative risks were estimated for drivers using combinations of drugs (adjusted OR 6.1 (95% Cl: 2.6-14.1)) and those using a combination of drugs and alcohol (OR 112.2 (95% Cl: 14.1-892)). Increased risks, although not statistically significantly, were assessed for drivers using amphetamines, cocaine, or opiates. No increased risk for road trauma was found for drivers exposed to cannabis. The study concludes that drug use, especially alcohol, benzodiazepines and multiple drug use and drug-alcohol combinations, among vehicle drivers increases the risk for a road trauma accident requiring hospitalisation.

Eating behavior and other distracting behaviors while driving among patients with eating disorders

The current study sought to better characterize eating behavior, binge-eating behavior, and other potentially problematic, distracting behaviors while driving in patients with eating disorders. Forty patients with eating disorders who reported eating in their car at least once per week were included. Thirty subjects with eating disorders reported binge-eating while driving. A surprisingly high number of subjects reported engaging in a variety of distracting behaviors, including changing clothes, reading, applying make-up, and combing/brushing their hair while driving. Potentially problematic behaviors such as binge-eating while driving should be inquired about during assessment, and if found should be addressed in treatment planning.

Association of main driver-dependent risk factors with the risk of causing a vehicle collision in Spain, 1990-1999

PURPOSE

To assess the strength of association of main driver-dependent risk factors with the risk of causing a collision between vehicles in Spain, from 1990 to 1999.

METHODS

The data for this paired-by-collision, case-control study were obtained from the Spanish Dirección General de Tráfico traffic crash database. The study included all 220284 collisions involving two or more vehicles with four or more wheels, in which only one of the drivers involved committed an infraction. Infractor drivers comprised the case group; noninfractor drivers involved in the same collision were their corresponding paired controls.

RESULTS

All driver-dependent factors were associated with the risk of causing a collision. The highest adjusted odds ratio estimates were obtained for sleepiness (64.35; CI, 45.12-91.79), inappropriate speed (28.33; CI, 26.37-30.44), and driving under the influence of alcohol with a positive breath test (22.32; CI, 19.64-25.37). An increase in the number of years in possession of a driving license showed a protective effect, albeit the strength of the effect decreased as age increased.

CONCLUSIONS

Our results emphasize the urgent need to implement strategies aimed mainly at controlling speeding, sleepiness, and alcohol consumption before driving-the main driver-dependent risk factors for causing a vehicle collision.

Behavioral, demographic, and prior morbidity risk factors for accidental death among men: a case-control study of soldiers

BACKGROUND

In the United States, the leading cause of death for young men is unintentional injury. The experience of the U.S. Army, because it comprises mostly young men, provides insights into factors associated with risk of accidental death. Between 1990 and 1998, accidents accounted for more than half of all deaths of men on active duty in the U.S. Army.

METHODS

All men on active duty in the U.S. Army who died in an accident between 1990 and 1998 were included in the study. For each accidental death case, four randomly selected controls were also included, matched on gender and contemporaneous military service.

RESULTS

In multivariate analyses, accidental death victims were more likely to be unmarried, limited to a high school education, in combat-specific occupations, veterans of a recent deployment, and previously hospitalized for an "injury/poisoning," "mental disorder," or "sign/symptom/ill-defined condition." Of behaviors reported on routine health risk assessments, the strongest predictor of a subsequent fatal accident was motorcycle use while the most excess deaths were attributable to consuming more than five alcoholic drinks per week.

CONCLUSIONS

There are characteristics, experiences, and behaviors that predict accidental death risk. The findings may inform safety and health promotion programs aimed at young adults.

Increased risk of traffic accidents in subjects with latent toxoplasmosis: a retrospective case-control study

BACKGROUND

The parasite Toxoplasma gondii infects 30-60% of humans worldwide. Latent toxoplasmosis, i.e., the life-long presence of Toxoplasma cysts in neural and muscular tissues, leads to prolongation of reaction times in infected subjects. It is not know, however, whether the changes observed in laboratory influence the performance of subjects in real-life situations.

METHODS

The seroprevalence of latent toxoplasmosis in subjects involved in traffic accidents (N=146) and in the general population living in the same area (N=446) was compared by a Mantel-Haenszel test for age-stratified data. Correlation between relative risk of traffic accident and a level of anti-Toxoplasma antibody titre was evaluated with the Cochran-Armitage test for trend.

RESULTS

A higher seroprevalence was found in the traffic accident set than in the general population (Chi2MH=21.45, p<0.0001). The value of the odds ratio (OR) suggests that subjects with latent toxoplasmosis had a 2.65 (C.I.95= 1.764.01) times higher risk of an accident than the toxoplasmosis-negative subjects. The OR significantly increased with level of anti-Toxoplasma antibody titre (p<0.0001), being low (OR=1.86, C.I.95=1.14-3.03) for the 99 subjects with low antibody titres (8 and 16), higher (OR=4.78, C.I.95=2.39-9.59) for the 37 subjects with moderate titres (32 and 64), and very high (OR=16.03, C.I.95=1.89-135.66) for the 6 subjects with titres higher than 64.

CONCLUSION

The subjects with latent toxoplasmosis have significantly increased risk of traffic accidents than the noninfected subjects. Relative risk of traffic accidents decreases with the duration of infection. These results suggest that 'asymptomatic' acquired toxoplasmosis might in fact represent a serious and highly underestimated public health as well as economic problem.