Antilock brakes and the risk of driver injury in a crash: a case-control study

While antilock brakes can improve steering and reduce stopping distance in some test situations, there is little evidence that they reduce the risk of crash-related injury. We sought to estimate the association between presence of antilock brakes and the risk of driver injury. We conducted a case-control study using claims data from the Insurance Corporation of British Columbia, Canada, for passenger vehicles insured during July 1, 2003, to June 30, 2004. Cases were 5000 vehicles with a driver crash injury during the study period. Controls were 49,994 vehicles insured at the mid-point of the study interval. The adjusted risk ratio for a crash with driver injury in a vehicle with antilock brakes was 1.06 (95% confidence interval, 0.95-1.17), compared with a vehicle without antilock brakes. If this estimated association is causal, antilock brakes do not prevent crash-related driver injuries.     

Drug use and fatal motor vehicle crashes: A case-control study

Drugged driving is a serious safety concern, but its role in motor vehicle crashes has not been adequately studied. Using a case-control design, the authors assessed the association between drug use and fatal crash risk. Cases (n = 737) were drivers who were involved in fatal motor vehicle crashes in the continental United States during specific time periods in 2007, and controls (n = 7719) were participants of the 2007 National Roadside Survey of Alcohol and Drug Use by Drivers. Overall, 31.9% of the cases and 13.7% of the controls tested positive for at least one non-alcohol drug. The estimated odds ratios of fatal crash involvement associated with specific drug categories were 1.83 [95% confidence interval (CI): 1.39, 2.39] for marijuana, 3.03 (95% CI: 2.00, 4.48) for narcotics, 3.57 (95% CI: 2.63, 4.76) for stimulants, and 4.83 (95% CI: 3.18, 7.21) for depressants. Drivers who tested positive for both alcohol and drugs were at substantially heightened risk relative to those using neither alcohol nor drugs (Odds Ratio = 23.24; 95% CI: 17.79, 30.28). These results indicate that drug use is associated with a significantly increased risk of fatal crash involvement, particularly when used in combination with alcohol.     

Alcohol, psychoactive drugs and fatal road traffic accidents in Norway: a case-control study

A case–control study was conducted on 204 drivers fatally injured in road traffic accidents in south-eastern Norway during the period 2003–2008. Cases from single vehicle accidents (N = 68) were assessed separately. As controls, 10 540 drivers selected in a roadside survey in the same geographical area during 2005–2006 were used. Blood samples were collected from the cases and oral fluid (saliva) samples from the controls. Samples were analysed for alcohol, amphetamines, cannabis, cocaine, opioid analgesics, hypnotics, sedatives and a muscle relaxant; altogether 22 psychoactive substances. Equivalent cutoff concentrations for blood and oral fluid were used. The risk for fatal injury in a road traffic accident was estimated using logistic regression adjusting for gender, age, season of the year, and time of the week. The odds for involvement in fatal road traffic accidents for different substances or combination of substances were in increasing order: single drug < multiple drugs < alcohol only < alcohol + drugs. For single substance use: medicinal drug or THC < amphetamine/methamphetamine < alcohol. For most substances, higher ORs were found when studying drivers involved in single vehicle accidents than for those involved in multiple vehicle accidents, but confidence intervals were wider.     

Alcohol, illicit and non-illicit psychoactive drug use and road traffic injury in Thailand: A case-control study

The objective of this study was to determine the relationship between alcohol use, psychoactive drug use and road traffic injury (RTI). A case-control study was conducted among drivers in Bangkok, Thailand. Two hundred cases and 849 controls were enrolled between February and November 2006. Cases who sustained a RTI were matched with four controls recruited from petrol stations within a 1-km radius of the reported crash site of the case.A positive alcohol breath test (≥50 mg/dl), and positive tests for the presence of illicit (amphetamine, cocaine, marijuana) and non-illicit psychoactive drugs (antihistamine, benzodiazepine, antidepressants), using gas chromatography/mass spectrometry (GC/MS) were documented as primary measures.There were significantly higher odds of an alcohol breath test ≥50 mg/dl (adjusted odds ratio (OR) 63.6 (95% CI: 25.5-158.9)), illicit psychoactive drugs (adjusted OR 3.4 (95% CI: 1.7-6.6)) and non-illicit psychoactive drug (adjusted OR 3.1 (95% CI: 1.5-6.3)) among cases than controls.Even though driving under the influence of psychoactive drugs has been significantly linked to RTI, its contribution to road safety is much lower than driving under the influence of alcohol. With limited resources, the priority for RTI prevention should be given to control of driving under the influence of alcohol.     

Car insurance and the risk of car crash injury

Despite speculation about the role of vehicle insurance in road traffic accidents, there is little research estimating the direction or extent of the risk relationship. Data from the Auckland Car Crash Injury Study (1998–1999) were used to examine the association between driving an uninsured motor vehicle and car crash injury. Cases were all cars involved in crashes in which at least one occupant was hospitalized or killed anywhere in the Auckland region. Controls were 588 drivers of randomly selected cars on Auckland roads. Participants completed a structured interview. Uninsured drivers had significantly greater odds of car crash injury compared to insured drivers after adjustment for age, sex, level of education, and driving exposure (odds ratio 4.77, 95% confidence interval 2.94–7.75). The causal mechanism for insurance and car crash injury is not easily determined. Although we examined the effects of multiple potential confounders in our analysis including socioeconomic status and risk-taking behaviours, both of which have been previously observed to be associated with both insurance status and car crash injury, residual confounding may partly explain this association. The estimated proportion of drivers who are uninsured is between 5 and 15% in developed countries, representing a significant public health problem worthy of further investigation.     

Driver health and crash involvement: a case-control study

The study investigates the relative crash involvement risk associated with diagnosed medical conditions, subjective symptoms and the use of some medicines based on self-report questionnaires from 4448 crash-involved drivers. Whereas many previous studies of medical conditions and crash risk have focussed exclusively on elderly drivers, this study included drivers of all ages. Relative risk for each health condition was estimated by comparing drivers with and without the condition, regarding the odds of being at fault for the crash. Statistical significance was tested by a logistic regression analysis for each condition with crash culpability as the dependent variable. Relative risks were expressed as odds ratios (OR) adjusted for age and annual driving distance. The analyses identified the following significant risk factors: non-medicated diabetes (OR=3.08), a history of myocardial infarction (OR=1.77), using glasses when driving (OR=1.26), myopia (OR=1.22), sleep onset insomnia (OR=1.87), frequent tiredness (OR=1.36), anxiety (OR=3.15), feeling depressed (OR=2.43) and taking antidepressants (OR=1.70). In addition, there was a relatively large and nearly significant relative risk for drivers who had suffered a stroke (OR=1.93). For some additional conditions the crude odds ratios were significant, but failed to reach significance after correction for age and annual driving distance.     

Economic development's effect on road transport-related mortality among different types of road users: a cross-sectional international study

The relationship between a country's stage of economic development and its motor vehicle crash (MVC) mortality rate is not defined for different road users. This paper presents a cross-sectional regression analysis of recent national mortality in 44 countries using death certificate data provided by the World Health Organization. For five types of road users, MVC mortality is expressed as deaths per 100,000 people and per 1000 motor vehicles. Economic development is measured as gross national income (GNI) per capita in U.S. dollars and as motor vehicles per 1000 people. Results showed overall MVC mortality peaked among low-income countries at about US$ 2000 GNI per capita and at about 100 motor vehicles per 1000 people. Overall mortality declined at higher national incomes up to about US$ 24,000. Most changes in MVC mortality associated with economic development were explained by changes in rates among nonmotorized travelers, especially pedestrians. Overall MVC rates were lowest when pedestrian exposure was low because there were few motor vehicles or few pedestrians, and were highest during a critical transition to motorized travel, when many pedestrians and other vulnerable road users vied for use of the roadways with many motor vehicles.     

The relationship between alcohol consumption patterns and car, work, sports and home accidents for different age groups

The purpose of this study was to examine the relationship between alcohol consumption patterns and car, work, sports and home accidents for different age groups. A secondary analysis of data from a randomized household survey of 10385 Canadians was conducted. Overall, alcohol consumption patterns were significantly associated with car collisions, work and sports accidents for younger age groups (i.e. 15-24 and 25-34), but this relationship was not significant for the older age groups.     

A small area study of motor vehicle crash fatalities in Alberta,Canada

This study examined the small area variation in motor vehicle crash fatality rates in the province of Alberta, Canada. Motor vehicle crash fatality rates per 100000 population (1995-1997, inclusive) were determined for five geographic areas in the province. The rates showed substantial, statistically significant variation across areas, with fatality rates lowest in the urban areas of Calgary and Edmonton, and highest in the rural areas (south, central, and northern Alberta). Examination of area-level predictors-population density, impaired driving citation rates, education level, unemployment levels, and ethnicity-showed that population density and impaired driving rates were associated with motor vehicle crash fatality rates. There was a five-fold difference in annual motor vehicle crash fatality rates between rural (22.9/100000) and urban areas (4.4/100000), whereas annual impaired driving rates were around 1.8% in rural areas, compared with 0.6% in urban areas. Because of multicollinearity problems, it was not possible to estimate a multivariable Poisson regression model. In conclusion, rural areas in the province of Alberta demonstrate a significantly higher motor vehicle crash fatality rate, compared with urban areas.     

Individual and occupational factors related to fatal occupational injuries: a case-control study

This study has been designed in order to identify factors increasing the risk of a fatal outcome when occupational accidents occur. The aim is to provide further evidence for the design and implementation of preventive measures in occupational settings. The Spanish Ministry of Labour registry of occupational injuries causing absence from work includes information on individual and occupational characteristics of injured workers and events. Registered fatal occupational injuries in 2001 (n = 539) were compared to a sample of non-fatal injuries in the same year (n = 3493). Risks for a fatal result of occupational injuries, adjusted by individual and occupational factors significantly associated, were obtained through logistic regression models. Compared to non-fatal injuries, fatal occupational injuries were mostly produced by trapping or by natural causes, mostly related to elevation and transport devices and power generators, and injured parts of body more frequently affected were head, multiple parts or internal organs. Adjusted analyses showed increased risk of fatality after an occupational injury for males (adjusted odds ratio aOR = 10.92; 95%CI 4.80–24.84) and temporary workers (aOR = 5.18; 95%CI 2.63–10.18), and the risk increased with age and with advancing hour of the work shift (p for trends <0.01). Injuries taking place out of the usual occupational setting (aOR = 2.85, 95%CI 2.27–3.59), or carrying out atypical tasks (aOR = 2.08; 95%CI 1.27–3.39) showed increased risks of a fatal result too, as occupational accidents in agricultural or construction companies. These data can help to select and define priorities for programmes aimed to prevent fatal consequences of occupational injuries.     

A case-control study of child bicycle injuries: relationship of risk to exposure

In order to assess the relationship of the risk of injury requiring hospital attendance in children riding bicycles to sociodemographic factors and to measures of exposure, a population-based case-control study is being undertaken in a large area of suburban Melbourne, Australia. Particular attention is given to the measurement of individual exposure in several dimensions. Analysis of interim data from 109 cases and 118 controls shows that 51% of injuries occurred while the child was playing rather than making a trip on the bicycle and only 22% involved another vehicle. Boys used bicycles more commonly than girls but there was minimal evidence of an increased risk of injury in boys, adjusting for exposure. There was no evidence for an age trend in injury risk, but children from families in the lowest income category were at significantly increased risk. Exposure measures showed complex patterns of association with injury risk. Estimated time spent riding was more closely associated with risk than distance travelled, with an odds ratio of 2.2 (95% confidence interval 1.1–4.2) for children riding for more than 3 hours per week compared to children riding less than 1 hour. Riding more than 5 km on the sidewalk was also associated with increased risk (odds ratio 3.1, 95% CI 1.1–8.5). The elevated risk associated with sidewalk riding may be due to difficulties in negotiating uneven surfaces. The case-control study provides an ideal design for this type of investigation but valid and reliable measurement of exposure is difficult.     

Alcohol consumption as an incremental factor in health care costs for traffic accident victims: Evidence in a medium sized Colombian city

Objectives

Identify the possibility that alcohol consumption represents an incremental factor in healthcare costs of patients involved in traffic accidents.

Methods

Data of people admitted into three major health institutions from an intermediate city in Colombia was collected. Socio-demographic characteristics, health care costs and alcohol consumption levels by breath alcohol concentration (BrAC) methodology were identified. Generalized linear models were applied to investigate whether alcohol consumption acts as an incremental factor for healthcare costs.

Results

The average cost of healthcare was 878 USD. In general, there are differences between health care costs for patients with positive blood alcohol level compared with those who had negative levels. Univariate analysis shows that the average cost of care can be 2.26 times higher (95% CI: 1.20–4.23), and after controlling for patient characteristics, alcohol consumption represents an incremental factor of almost 1.66 times (95% CI: 1.05–2.62).

Conclusions

Alcohol is identified as a possible factor associated with the increased use of direct health care resources. The estimates show the need to implement and enhance prevention programs against alcohol consumption among citizens, in order to mitigate the impact that traffic accidents have on their health status. The law enforcement to help reduce driving under the influence of alcoholic beverages could help to diminish the economic and social impacts of this problem.     

An exposure based study of crash and injury rates in a cohort of transport and recreational cyclists in New South Wales,Australia

This paper examines self-reported prospectively collected data from 2038 adult transport and recreational cyclists from New South Wales (Australia) to determine exposure-based incident crash and injury rates. During 25,971 days of cycling, 198 crashes were reported, comprising approximately equal numbers of falls and collisions. The overall crash rate was 0.290 (95% CI, 0.264–0.319) per 1000 km or 6.06 (95% CI, 5.52–6.65) per 1000 h of travel. The rate of crashes causing any injury (self-treated, or medically attended without overnight hospital stay) was 0.148 (95% CI, 0.133–0.164) per 1000 km or 3.09 (95% CI, 2.79-3.43) per 1000 h of travel. The rate of crashes causing a medically attended injury (without overnight hospital stay) was 0.023 (95% CI, 0.020–0.027) per 1000 km or 0.49 (95% CI, 0.43-0.56) per 1000 h of travel. No injuries requiring an overnight stay in hospital were reported on days meeting the inclusion criteria. After adjustment for exposure in hours, or for the risks associated with different infrastructure utilisation, the rates of crashes and medically attended injuries were found to be greater for females than males, less experienced than more experienced cyclists, and for those who rode mainly for transport rather than mainly for recreation. Comparison of estimated crash and injury rates on different infrastructure types were limited by the small number of events, however findings suggest that the separation of cyclists from motorised traffic is by itself not sufficient to ensure safe cycling.     

The use of electronic pharmacy data to investigate prescribed medications and fatal motor vehicle crashes in a military population, 2002-2006

The authors examined the association between prescribed medications and fatal motor vehicle crashes (MVCs) in an active duty military population between 2002 and 2006. Using a case-control design, MVC deaths were ascertained using a military mortality registry, and an integrated health system database provided information on health system eligibility, pharmacy transactions, and medical encounters. Cases and controls were matched on comparable observation time outside periods of deployment. Among selected categories, only one, antidepressant medications, was an independent predictor of fatal MVC (odds ratio, 3.19; 95% confidence interval, 1.01-10.07). Male gender, Black race, enlisted rank, service branch (Navy and Marine Corps), and selected co-morbidities were also independent predictors. Unexpectedly, the odds of younger age quartiles (<27 years) and history of deployment were reduced for MVC cases. Although results need to be considered in the context of data limitations, the association between prescribed antidepressants and fatal MVC may reflect unmeasured co-morbidities, such as combined effects of prescribed and over-the-counter medications and/or alcohol or other substance abuse. Younger individuals, representing new military accessions in training or returning from deployment with serious injuries, may have fewer opportunities to operate vehicles, or targeted efforts to reduce MVC following deployment may be showing a positive effect.     

Characteristics,cycling patterns,and crash and injury experiences at baseline of a cohort of transport and recreational cyclists in New South Wales,Australia

This paper examines self-reported retrospective data for a 12 month period from 2038 adult cyclists from New South Wales (Australia), and compares cyclists according to whether they self-identify as riding mainly for transport or mainly for recreation. Statistically significant differences were found in the demographic characteristics, cycling patterns, and crash experiences between these two groups of cyclists. Transport cyclists tended to be younger, travel more days per week, and within morning and evening peak hours than recreational cyclists; recreational cyclists were more likely to identify fitness as a purpose for cycling. The proportion of cyclists experiencing a crash or crash-related injury in the previous 12 months was similar for transport and recreational cyclists, but there were differences in crash types and location which likely reflect different cycling environments. Heterogeneity within transport and recreational cyclists was also found, based on self-reported riding intensity. An understanding of the different cycling patterns and experiences of various types of cyclists is useful to inform road safety, transport and health promotion policy.     

Cause, effect and regression in road safety: A case study

Researchers use various ways to determine what change in safety is caused by some treatment. One way is to fit regression equations to cross-section data. Can this work? Another way is to do a before-after study. Is this better? I examine these questions in the setting of a case study. The treated units are rail-highway grade crossings, the treatment is the replacement of ‘crossbucks’ by ‘flashers’, and as evidence serve published papers and reports.The results of regression studies are all over the place. Still, one cannot be sure whether this is a sign that the regression failed to capture cause and effect or a sign that the effect of this treatment depends strongly on the conditions in which it is applied. As different regressions use different variables, they cannot corroborate or negate each other's results. This is deeply troubling.The results of before-after studies, in this case, are very consistent. Unfortunately the results do not apply to specific conditions and are therefore of limited practical use. In this respect crash modification functions derived from regressions would have an inherent advantage over those from before-after studies provided they captured cause and effect. There is, at present, little ground for the belief that they do.     

Road crash involvement and professional status: a prospective study using the French Gazel cohort

OBJECTIVES: To assess professional status (PS) differences in the risk of road crash involvement (RCI) (irrespective of crash severity), and to examine the underlying mechanism by evaluating the role of exposure to road risk (ERR). METHOD: A total of 15,271 subjects selected from the French GAZEL cohort were studied. A proportional hazard model for recurrent events was used to calculate the relative risks (RR) of RCI associated with PS. The associations between RCI and PS were investigated by adjusting for ERR (kilometers travelled and risk behaviors on the road). RESULTS: In all, 1890 RCI were reported. Managers have greater crude RCI risk than unskilled workers (male, RR=1.30; female, RR=1.44). This difference was no longer statistically significant when adjusting for factors describing the drivers' behaviors. Female managers' risks were also insignificant when adjusted for vehicle kilometers travelled (VKT). Managers seemed at lower risk of injury when involved in a crash. CONCLUSION: Socially advantaged subjects have the greatest RCI risk. Qualitative and quantitative ERR factors explain these disparities. These results highlight the importance to focus on ERR when studying the effect of an individual characteristic on RCI. They also highlight the importance to analyse separately the "RCI" and the "susceptibility to injury".     

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 1 h 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.     

Association of cyclists’ age and sex with risk of involvement in a crash before and after adjustment for cycling exposure

This study aimed to estimate the association of cyclists’ age and sex with the risk of being involved in a crash with and without adjustment for their amount of exposure. We used the distribution of the entire population and cyclists (total and non-responsible) involved in road crashes in Spain between 1993 and 2009 held by the Spanish National Institute of Statistics and the Spanish General Traffic Directorate to calculate rates of exposure and involvement in a crash. Males aged 45–49 years were used as the reference category to obtain exposure rate ratios (ERR) and unadjusted crash rate ratios (URR). We then used these values in decomposition analysis to calculate crash rate ratios adjusted for exposure (ARR). The pattern of ARR was substantially different from URR. In both sexes the highest values were observed in the youngest age groups, and the values decreased as age increased except for a slight increase in the oldest age groups. In males, a slight increase in the lowest and highest age categories was observed for crashes resulting in severe injury or death, and a decrease was observed for the youngest cyclists who were wearing a helmet. The large differences between age and sex groups in the risk of involvement in a cycling crash are strongly dependent on differences in their exposure rates. Taking exposure rates into account, cyclists younger than 30 years and older than 65 years of age had the highest risk of being involved in a crash.