Single-bicycle crashes: An in-depth analysis of self-reported crashes and estimation of attributable hospital cost.

Cyclists' awareness of their risk of single-bicycle crashes is limited. Thus, knowledge of the most common contributory factors of single-bicycle crashes is required. Similarly, single-bicycle crashes and their costs to society are under-recognized by the public. The aim of this study was to conduct an analysis of single-bicycle crashes occurring in a cohort of cyclists in Denmark and supplement it with estimation of some attributable costs of single-bicycle crashes among all injured cyclists during one year treated in a hospital or emergency room in Denmark. We conducted a one-year follow-up of 6,793 active cyclists (mean age: 45.8 years) encountering 349 single-bicycle crashes (single-bicycle crash rate: 55 per 1,000 person-years). An in-depth analysis of the crashes suggested that daily winter road maintenance is crucial in colder climates and that the current cyclist infrastructure design gives rise to many single-bicycle crashes. Further analysis of the co-occurrence of the factors contributing to the crashes indicated that when the weather is warmer, the factors pertaining to the individual cyclist (and not the road authorities) dominate. The risk of sustaining a more severe injury (i.e. other than light bruises) once in a single-bicycle crash was 18 %. However, for cyclists above 50 years, this risk doubled compared with their younger counterparts, wholly due to a 4.7 times higher risk during the warm season. Among cyclists treated in hospital or emergency room, we estimated the attributable hospital cost of single-bicycle crashes at €1,701 and the attributable cost of municipality care at €417 in the first year after the injury (2019 prices). In cyclists aged 18-60 years and treated in hospital or emergency room, the estimated attributable risk of sickness benefit was 5.2 percentage points in the first year after the injury. We concluded that to increase cyclist safety, the road authorities should improve winter road maintenance and redesign cyclist infrastructure.

Updated estimates of the relationship between speed and road safety at the aggregate and individual levels.

Recent studies of the relationship between the speed of traffic and road safety, stated as the number of fatalities and the number of injury accidents, are reviewed and their results synthesised by means of meta-analysis. All studies were based on data fully or partly for years after 2000. Previously proposed models of the relationship between the speed of traffic and road safety, including the Power Model and an Exponential Model, are supported. Summary estimates of coefficients show that the relationship between speed and road safety remains strong. The Power Model and the Exponential Model both fit the data very well. The relationship between speed and road safety is the same at the individual driver level as at the aggregate level referring to the mean speed of traffic.

Understanding traffic crash under-reporting: Linking police and medical records to individual and crash characteristics.

OBJECTIVE: This study aligns to the body of research dedicated to estimating the underreporting of road crash injuries and adds the perspective of understanding individual and crash factors contributing to the decision to report a crash to the police, the hospital, or both. METHOD: This study focuses on road crash injuries that occurred in the province of Funen, Denmark, between 2003 and 2007 and were registered in the police, the hospital, or both authorities. Underreporting rates are computed with the capture-recapture method, and the probability for road crash injuries in police records to appear in hospital records (and vice versa) is estimated with joint binary logit models. RESULTS: The capture-recapture analysis shows high underreporting rates of road crash injuries in Denmark and the growth of underreporting not only with the decrease in injury severity but also with the involvement of cyclists (reporting rates of about 14% for serious injuries and 7% for slight injuries) and motorcyclists (reporting rates of about 35% for serious injuries and 10% for slight injuries). Model estimates show that the likelihood of appearing in both data sets is positively related to helmet and seat belt use, number of motor vehicles involved, alcohol involvement, higher speed limit, and females being injured. CONCLUSIONS: This study adds significantly to the literature about underreporting by recognizing that understanding the heterogeneity in the reporting rate of road crashes may lead to devising policy measures aimed at increasing the reporting rate by targeting specific road user groups (e.g., males, young road users) or specific situational factors (e.g., slight injuries, arm injuries, leg injuries, weekend).

Effectiveness of electronic stability control on single-vehicle accidents.

OBJECTIVE: This study aims at evaluating the effectiveness of electronic stability control (ESC) on single-vehicle injury accidents while controlling for a number of confounders influencing the accident risk. METHODS: Using police-registered injury accidents from 2004 to 2011 in Denmark with cars manufactured in the period 1998 to 2011 and the principle of induced exposure, 2 measures of the effectiveness of ESC were calculated: The crude odds ratio and the adjusted odds ratio, the latter by means of logistic regression. The logistic regression controlled for a number of confounding factors, of which the following were significant. For the driver: Age, gender, driving experience, valid driving license, and seat belt use. For the vehicle: Year of registration, weight, and ESC. For the accident surroundings: Visibility, light, and location. Finally, for the road: Speed limit, surface, and section characteristics. RESULTS: The present study calculated the crude odds ratio for ESC-equipped cars of getting in a single-vehicle injury accident as 0.40 (95% confidence interval [CI], 0.34-0.47) and the adjusted odds ratio as 0.69 (95% CI, 0.54-0.88). No difference was found in the effectiveness of ESC across the injury severity categories (slight, severe, and fatal). CONCLUSIONS: In line with previous results, this study concludes that ESC reduces the risk for single-vehicle injury accidents by 31% when controlling for various confounding factors related to the driver, the car, and the accident surroundings. Furthermore, it is concluded that it is important to control for human factors (at a minimum age and gender) in analyses where evaluations of this type are performed.

Risk of severe driver injury by driving with psychoactive substances.

Driving with alcohol and other psychoactive substances imposes an increased risk of severe injury accidents. In a population-based case-control design, the relative risks of severe driver injury (MAIS≥2) by driving with ten substance groups were approximated by odds ratios (alcohol, amphetamines, benzoylecgonine, cocaine, cannabis, illicit opiates, benzodiazepines and Z-drugs, i.e. zolpidem and zopiclone, medicinal opioids, alcohol-drug combinations and drug-drug combinations). Data from six countries were included in the study: Belgium, Denmark, Finland, Italy, Lithuania and the Netherlands. Case samples (N=2490) were collected from severely injured drivers of passenger cars or vans in selected hospitals in various regions of the countries. Control samples (N=15,832) were sampled in a uniform sampling scheme stratified according to country, time, road type and season. Relative risks were approximated by odds ratios and calculated by logistic regression. The estimates were adjusted for age, gender and country. The highest risk of the driver being severely injured was associated with driving positive for high concentrations of alcohol (≥0.8 g/L), alone or in combination with other psychoactive substances. For alcohol, risk increased exponentially with blood alcohol concentration (BAC). The second most risky category contained various drug-drug combinations, amphetamines and medicinal opioids. Medium increased risk was associated with medium sized BACs (at or above 0.5 g/L, below 0.8 g/L) and benzoylecgonine. The least risky drug seemed to be cannabis and benzodiazepines and Z-drugs. For male drivers, the risk of being severely injured by driving with any of the psychoactive substances was about 65% of that of female drivers. For each of the substance groups there was a decrease in the risk of severe driver injury with increasing age. It is concluded that among psychoactive substances alcohol still poses the largest problem in terms of driver risk of getting injured.

Analyzing the relationship between car generation and severity of motor-vehicle crashes in Denmark.

While the number of fatalities on Danish roads has decreased in the last 40 years, research has not investigated the contribution of legislation changes, enforcement measures, technological enhancements, infrastructural improvements and human factors to this reduction. In the context of a Danish car market with remarkably high registration tax that causes potential buyers to hold longer onto old cars, the relationship between technological enhancements of vehicles and severity of crashes requires particular attention. The current study investigated the relationship between car generation (i.e., car's first registration year) and injury severity sustained by car drivers involved in accidents in Denmark between 2004 and 2010. A generalized ordered logit model was estimated while controlling for several characteristics of the crash, the vehicle and the persons involved, and a sensitivity analysis was performed to assess the effect of car generation on drivers' injury severity. Results illustrate that newer car generations are associated to significantly lower probability of injury and fatality, and that replacing older cars with newer ones introduces significant and not to be overlooked benefits for both population and society.

Random and systematic errors in case-control studies calculating the injury risk of driving under the influence of psychoactive substances.

Between 2006 and 2010, six population based case-control studies were conducted as part of the European research-project DRUID (DRiving Under the Influence of Drugs, alcohol and medicines). The aim of these case-control studies was to calculate odds ratios indicating the relative risk of serious injury in car crashes. The calculated odds ratios in these studies showed large variations, despite the use of uniform guidelines for the study designs. The main objective of the present article is to provide insight into the presence of random and systematic errors in the six DRUID case-control studies. Relevant information was gathered from the DRUID-reports for eleven indicators for errors. The results showed that differences between the odds ratios in the DRUID case-control studies may indeed be (partially) explained by random and systematic errors. Selection bias and errors due to small sample sizes and cell counts were the most frequently observed errors in the six DRUID case-control studies. Therefore, it is recommended that epidemiological studies that assess the risk of psychoactive substances in traffic pay specific attention to avoid these potential sources of random and systematic errors. The list of indicators that was identified in this study is useful both as guidance for systematic reviews and meta-analyses and for future epidemiological studies in the field of driving under the influence to minimize sources of errors already at the start of the study.

Alcohol and drugs in seriously injured drivers in six European countries.

The objective of this study was to determine the presence of alcohol and drugs in drivers severely injured in traffic crashes in six European countries. Data were collected from 2492 seriously injured drivers of cars and vans in Belgium, Denmark, Finland, Italy, Lithuania, and the Netherlands, between 2007 and 2010. Toxicological analysis was performed with chromatographic techniques on whole blood for 23 substances. The percentage of drivers positive for at least one psychoactive substance ranged between 28% (Lithuania) and 53% (Belgium). Alcohol (≥0.1 g/L) was the most common finding with the highest percentage in Belgium (42.5%). Among the alcohol-positive drivers, 90.5% had a blood alcohol count (BAC) ≥0.5 g/L and 65.7% had a BAC ≥1.3 g/L. Benzodiazepines (0.0-10.2%) and medicinal opioids (0.5-7.8%) were the most prevailing medicinal drugs, but half of the concentrations were lower than therapeutic. Cannabis (0.5-7.6%) was the most prevailing illicit drug. Alcohol was found in combination with drugs in 2.3-13.2% of the drivers. Drug combinations were found in 0.5-4.3% of the drivers. This study confirms the high prevalence of psychoactive substances in injured drivers, but we observed large differences between the participating countries. Alcohol was the most common finding, followed by cannabis and benzodiazepines. Notable are the many drivers having a BAC ≥ 1.3 g/L. The majority of the substances were found in combination with another psychoactive substance, mostly alcohol. The high prevalence of high BACs and combinations (compared to roadside surveys) suggest that those drivers are most at risk and that preventive actions should target them preferentially.

Trends in drink driving accidents and convictions in Denmark.

OBJECTIVE: The objective of this article is to describe the long-term trends in injury accidents involving drink drivers and in drink driving convictions in Denmark. The article also identifies drink drivers' characteristics useful for targeted countermeasures. METHOD: Accident-involved drink drivers have been divided into subgroups by age and gender. The database of convicted drivers has been linked to databases with information about age, gender, and various socio-demographic variables, such as education and employment. Per capita rates have been used to describe the changes in the road safety variables and in the criminal convictions variables during the study period. RESULTS: In the past four decades there has been a sharp reduction in the per capita rate of Danish male drink drivers involved in injury accidents for all age groups, with the slope of the curve significantly lower in recent years. Although this rate reduction is much more marked for male drivers aged 18-24 compared to all other age groups, their rate is still around three times higher than for those aged 25-64. Danish male convicted drink drivers, including those who were involved in accidents, are mainly drivers with only primary school education or workers, unemployed drivers, and drivers who use their car for work. CONCLUSION: Strategies against drink driving should bear in mind that a differentiation between men and women and young people and middle-aged people is necessary, that education and occupation play an important role, that drink driving may be related to the workplace, and that enforcement activities towards young drivers should be concentrated on weekends.

Cyclists' perception of risk in roundabouts.

Converting an intersection into a roundabout improves motor vehicle safety, but a similar safety effect is not found for car-bicycle collisions. Very little is known about the reasons behind these collisions. In this study a first step towards an understanding of the reasons behind these collisions is taken. The study focuses on cyclists' perceived risk in specific situations, factors influencing the perception of risk and cyclists' knowledge about traffic rules regulating the interaction between road users in roundabouts. One thousand and nineteen cyclists aged 18-85 participated in the study. Data were collected using structured interviews conducted in five Danish roundabouts. Underestimation of risk and lack of knowledge about relevant traffic rules may contribute to car-bicycle collisions in roundabouts. Cyclists prefer road designs with a clear regulation of road user behaviour. A need to increase knowledge about traffic rules regulating road user behaviour in roundabouts is identified.

The effect of roundabout design features on cyclist accident rate.

Roundabouts are known to result in fewer traffic accidents than traditional intersections. However, this is to a lesser degree true for bicycles than for vehicles. In this paper, we aimed at establishing statistical relationships through Poisson regression and logistic regression analyses between yearly rate of cyclist accidents on one hand and roundabout geometry, age and traffic volume (vehicles and cyclists) on the other. We related all roundabout cyclist accidents recorded by the hospital emergency department of the town of Odense, Denmark, through the years 1999-2003 (N=171) to various geometric features, age and traffic volume of all roundabouts on the Danish island of Funen (N=88). Cyclist and vehicle volumes turned out to be significant predictors in most of our models-the higher the volumes, the more accidents. Moreover, potential vehicle speed was a significant predictor, and so was age of the roundabout-older roundabouts related to more accidents and higher accident probability. Excluding 48 single cyclist accidents strengthened the relationship between accidents on one hand and vehicle and cyclist volume and potential vehicle speed on the other. This stresses the significance of speed and traffic volume for traffic accidents with more than one partner involved. The 48 single cyclist accidents were significantly related to the traffic volume of cyclists only. Due to our limited number of observations, the models should be regarded as indicative.

Extent and variations in mobile phone use among drivers of heavy vehicles in Denmark.

A substantial body of research has shown that use of mobile phones while driving can impair driving performance and increase the risk of being involved in accidents. Similarly, mobile phone use seems to be an increasing activity thus representing a relevant traffic safety issue. This paper investigates the extent and variations in mobile phone use among drivers of heavy vehicles in Denmark. The data was collected through written questionnaires and had a response rate of 58%. It was found that more than 99% of the drivers used mobile phones while driving. Despite a prohibition of hand-held mobile phone use while driving 31% of the drivers reported to do so. Analysis of the variations in usage found a positive significant relationship between driving hours and phone use. A negative linear effect was found between age and phone use. Similarly, a positive significant association was found between the number of stops and the amount of phone use. 0.5% reported that their use of mobile phones had contributed to an accident, while 6% had experienced their mobile phone use causing a dangerous situation. However, 66% reported experiencing dangerous situations because of others road users' mobile phone use. Various implications of the findings are discussed particularly in relation to the drivers with high exposure.

Factors affecting the phase-out of pesticide use in public areas in Denmark.

That pesticide use in public areas in Denmark has been significantly reduced during the period 1995 to 2002 is shown when comparing three surveys carried out by the Danish Forest and Landscape Research Institute (DFLRI) with funding from the Danish Environmental Protection Agency. During that period, the total registered public use of pesticides was reduced from 28.8 tonnes active ingredients to 6.3 tonnes, corresponding to a 78% reduction. In 2002, the Danish counties and state institutions had reduced their total pesticide use by 80% and 73%, respectively, compared to 1995 figures. Similarly, the Danish municipalities reduced their use by 83% from 1995 to 2002. Surveys of municipal pesticide use carried out in 1995, 2000 and 2002 have been used as the basis for determining the factors that have influenced municipal reductions of pesticide use. The 2000 and 2002 trends can be explained partly on the basis of the figures for 1995 use. The trend for 2002 can also be partially explained by the political parties in power in the municipalities during the phase-out period. The models used account for up to 30% of the total variations, meaning that the pesticide use of individual municipalities is very much influenced by other, non-definable factors such as tradition.