Prevalence of alcohol and drugs among car and van drivers killed in road accidents in Norway: an overview from 2001 to 2010

Prevalence of alcohol and drugs among drivers killed in road traffic crashes in Norway during 2011-2020

OBJECTIVE

Driving under the influence of alcohol or drugs is one of the main contributing causes of serious road traffic crashes (RTCs). This study aimed to investigate the involvement of alcohol and drugs in driver fatalities in Norway during 2011-2020 and compare the findings with data from the previous decade.

METHODS

We linked the results of forensic toxicology testing for alcohol and the 17 most commonly used drugs assigned with legal limits with data on fatal road traffic crashes obtained from Statistics Norway and the Norwegian Public Roads Administration.

RESULTS

The number of fatalities had decreased significantly since the previous decade, while the proportion of drivers and riders tested for alcohol and drug use increased. Blood alcohol concentrations at the legal limit or higher were found in 14.4% and psychoactive drugs were detected in 15.8% of the cases; 10.7% tested positive for illicit drugs, and 10.1% for medicinal drugs. The most prevalent illicit drugs were tetrahydrocannabinol (7.9%) and amphetamine/methamphetamine (4.7%), whereas the most prevalent medicinal drugs were clonazepam (3.7%) and diazepam (2.2%).

CONCLUSIONS

There was a marked reduction in the number of motor vehicle drivers killed in RTCs compared with the previous decade, and also a reduction in the prevalence of alcohol. For other substances, there were no marked changes in the prevalence.

Estimate of the magnitude of risky and protective behaviors associated with road traffic injuries in capitals participating in the Life in Traffic Project of Brazil

BACKGROUND

Brazil occupies the fifth position in the ranking of the highest mortality rates due to RTI in the world. With the objective of promoting traffic safety and consequently reducing deaths, Brazil created the Life in Traffic Project (LTP). The main goal of LTP is reducing 50% of RTI deaths, by promoting interventions to tackle risk factors, such as driving under the influence of alcohol and excessive and/or inappropriate speed. Thus, the aim of this study was to estimate the magnitude of risky and protective factors for RTI in capitals participating in the LTP in Brazil. We estimated these factors according to sociodemographic (age group, sex, education, race and, type of road user).

METHODS

A total of 5,922 car drivers and motorcyclists from 14 Brazilian capitals participating in the LTP were interviewed. Data collection was carried out in sobriety checkpoints at night and consisted of the administration of an interview and a breathalyzer test. Risky and protective behaviors associated with RTI were investigated. Covariates of the study were: age, sex, education, race and, type of road user. Poisson multiple regression analysis was used to assess the relationship between variables of interest.

RESULTS

The prevalence of individuals with positive blood alcohol concentration (BAC) was 6.3% and who reported driving after drinking alcohol in the last 30 days was 9.1%. The others risky behaviors reported were: driving at excessive speed on roads of 50 km/h, using a cell phone for calls while driving, using a cell phone to send or read calls while driving, running a red light. Use of seatbelts and helmets showed prevalence above 96,0% Use of seatbelts showed prevalence of 98.6% among car drivers, and helmet use was described by 96.6% of motorcycle drivers. Most risky behaviors were more prevalent in younger age groups (except BAC measurement higher in older participants), in males (except for cell phone use), in participants with higher education level and without a driver's license.

CONCLUSION

Excessive speed and driving under the influence of alcohol, defined as priorities within the LTP, need more consistent interventions, as they still have considerable prevalence in the cities investigated. The factors described such as cell phone usage and passing red traffic lights should also need to be prioritized as a focus on promoting traffic safety.

High-risk motor vehicle drivers engage in more risk behaviors than motorcyclists

Objective: The purpose of this study was to characterize and compare risk behaviors between motorcyclists and motor vehicle drivers who were involved in accidents and required hospitalization. The study focused on patients who were recently involved in motorcycle collisions (MCCs) and motor vehicle collisions (MVCs). Methods: We identified 63 patients involved in MCCs and 39 patients involved in MVCs who were admitted to our level-1 trauma center from April 2014 to September 2015. These 102 patients completed a questionnaire designed to evaluate risky driving behaviors. Pearson’s chi-squared tests and unpaired two-tailed t-tests were used to evaluate categorical and normally distributed continuous variables, respectively. Multivariable linear regression was used to analyze predictors of risk behavior. Significance was set at p < 0.05. Results: When compared to patients involved in an MCC, patients involved in MVCs were more likely to be female (p = 0.007), drive more frequently (p < 0.001), and never perceive the risk of an accident (p = 0.036). MVC patients were more likely to have admitted to substance use on the day of the accident (p = 0.030), historically drive under the influence of drugs (p = 0.031), drive while tired (p < 0.001), drive while text messaging (p < 0.001), and speed while overtaking vehicles (p = 0.011). Overall, MVC patients engaged in more risk behaviors (3.3 ± 1.3 vs. 2.0 ± 1.5; p < 0.001) and were more likely to engage in multiple risk behaviors (p < 0.001). MVCs were associated with increased risk behavior, even after controlling for protective behaviors, driving history, and demographics (p = 0.045). Conclusions: Within our cohort of trauma patients at our institution, motor vehicle drivers were more likely than motorcyclists to engage in any one risk behavior and engage in a higher number of risk behaviors. In addition, motor vehicle drivers perceived their risk of a potential accident as lower than riding a motorcycle. Education initiatives should focus on motor vehicle driver safety interventions that reduce risk behaviors.

The prevalence of alcohol and other drugs in fatal road crashes in Victoria, Australia

BACKGROUND

Driving under the influence of drugs, including alcohol, is a globally recognised risk factor for road traffic crashes. While the prevalence of alcohol and other drugs in fatal road crashes has been examined in other countries, recent data investigating drug driving in fatal Australian crashes are limited. This study aimed to examine how the presence of alcohol and other drugs in fatal road trauma in Victoria has changed over time in different road users.

METHODS

A population-based review of road trauma deaths was performed over the period of 01 July 2006 to 30 June 2016 in Victoria, Australia, using data from the National Coronial Information System (NCIS) and the Victorian State Trauma Registry (VSTR). Drugs were grouped according to type and analysed accordingly. Poisson regression models were used to determine change in incidence rates over the study period.

RESULTS

There were 2287 road traffic fatalities with complete toxicology data (97% of all road traffic fatalities). Alcohol (blood alcohol concentration, BAC) was the most commonly detected drug (>0.001 g/100 mL: 21.1%; >0.05 g/100 mL: 18.4%), followed by opioids (17.3%), THC (13.1%), antidepressants (9.7%), benzodiazepines (8.8%), amphetamine-type stimulants (7.1%), ketamine (3.4%), antipsychotics (0.9%) and cocaine (0.2%). Trends demonstrated changing use over time with specific drugs. Alcohol positive road fatalities declined 9% per year in passenger car/4WD drivers (IRR = 0.91, 95% CI: 0.88-0.95). The incidence of strong opioids (oxycodone, fentanyl, morphine, and methadone) increased 6% per year (IRR = 1.06; 95% CI: 1.02-1.10). Methylamphetamine was detected in 6.6% of cases and showed a yearly increase of 7% (IRR = 1.07; 95% CI: 1.01-1.13). The incidence of THC remained unchanged over the period, observed in 13.1% of cases. Stronger opioids were more commonly detected among pedal cyclists (19.0%) and pedestrians (20.9%) while THC was more commonly detected among motorcyclists (19.8%) and other light vehicle drivers (17.6%).

CONCLUSIONS

A decline in the prevalence of alcohol in fatalities suggests that law enforcement and public health strategies in Australia to address road fatalities and drink-driving may have had a positive effect. However, increases were observed in the incidence of other potentially impairing drugs including opioids and amphetamines, specifically methylamphetamine, indicating a concerning trend in road safety in Victoria that warrants further monitoring.

Alcohol and drug use among road users involved in fatal crashes in Norway

OBJECTIVE

To study the prevalence of alcohol and drugs in biological samples from drivers, motorcycle riders, bicyclists, and pedestrians involved in fatal road traffic crashes (RTCs) during 2016-2018 in Norway, both among fatally injured victims and those who survived fatal RTCs.

METHODS

Anonymous information was extracted from police data. No personal data were recorded.

RESULTS

There were 330 fatal RTCs with 349 killed road users and 384 survivors during the study period; this included 179 passengers who were excluded from the study. In total, 90% of the studied killed road users and 67% of the survivors were investigated for alcohol or drug use by analyzing biological samples. Alcohol or drugs in concentrations above the legal limits were detected in 21% of the analyzed samples. The proportion impaired by alcohol or drugs (blood alcohol concentrations equal to or greater than 0.05%, or drug concentrations above equivalent limits) was highest among killed bicyclists (43%), higher than among killed pedestrians (24%), car and van drivers (28%) and motorcyclists (20%), and significantly higher than among drivers who survived fatal crashes (4%).

CONCLUSIONS

Impairment due to use of alcohol or drugs was often a contributing factor among bicyclists, pedestrians and motor vehicle drivers who died in RTCs. Driving under the influence of alcohol or drugs was more often a contributing factor in cases where the motor vehicle driver was killed than in cases where the driver survived.

A short survival time after last psychiatric hospitalization in drivers with psychotic disorder killed in fatal motor vehicle accidents

BACKGROUND

Research-based evidence on patients with psychotic disorders involved in fatal motor vehicle accidents (FMVA) remains limited. The current study analyzes the characteristics of FMVA drivers, who had been hospitalized due to psychotic disorders within a five-year-time-period prior to their death in traffic accidents.

MATERIAL AND METHODS

Data sources included three national registers: The Finnish Database of Road and Cross-Country Accidents, the Care Register for Health Care and the National Cause of Death Register. The register-linkage was made using personal identity codes, unique for each Finnish citizen. The initial study population consisted of 4930 drivers killed in FMVA in Finland between the years 1990-2011. A total of 94 (1.9%) Finnish drivers had a hospital-diagnosed psychotic disorder made during the five years preceding their FMVA. The psychotic disorders of the study subjects were categorized into: schizophrenia (n = 27, 28.7%), other specified psychoses (n = 39, 41.5%) and unspecified psychoses (n = 28, 29.8%).

RESULTS

About one half of the FMVA drivers with schizophrenia or unspecified psychoses and 41% of those with other specified psychoses had been discharged from psychiatric care within three months prior to their death in traffic accidents.

CONCLUSIONS

Based on our study findings and the lack of concise guidelines for assessing psychotic patients' fitness-to-drive, we recommend a minimum temporary driving restriction of three months for all patients after hospitalization for psychosis.

Driving Under the Influence of Cannabis: A Framework for Future Policy

Marijuana is the most widely consumed illicit substance in the United States, and an increasing number of states have legalized it for both medicinal and recreational purposes. As it becomes more readily available, there will be a concurrent rise in the number of users and, consequently, the number of motor vehicle operators driving under the influence. This article examines the cognitive and psychomotor effects of cannabis, as well as current policy concerning driving under the influence of drugs. The authors performed a MEDLINE search on the epidemiology of cannabis use, its cognitive and psychomotor effects, and policies regarding driving under the influence of drugs. Twenty-eight epidemiological studies, 16 acute cognitive and psychomotor studies, 8 chronic cognitive and psychomotor studies, and pertinent state and federal laws and policies were reviewed. These search results revealed that marijuana use is associated with significant cognitive and psychomotor effects. In addition, the legalization of marijuana varies from state to state, as do the laws pertaining to driving under the influence of drugs. Marijuana is a commonly found illicit substance in motor vehicle operators driving under the influence of drugs. Current evidence shows that blood levels of tetrahydrocannabinol do not correlate well with the level of impairment. In addition, although acute infrequent use of cannabis typically leads to cognitive and psychomotor impairment, this is not consistently the case for chronic heavy use. To establish the framework for driving under the influence of cannabis policy, we must review the current published evidence and examine existing policy at state and federal levels.

The use of medication and alcohol in recreational downhill skiers: Results of a survey including 816 subjects in Tyrol

OBJECTIVE

The aim of this study was to collect data on the medication and alcohol use in recreational downhill skiers.

DESIGN

Cross-sectional study.

METHODS

The study was conducted during the 2014 winter season in different ski resorts in Tyrol, Austria. Participants were asked to complete a brief survey including questions about basic anthropometric data (age, stature, weight) the use of medication (yes/no) and alcohol intake on the skiing day or the day before (yes/no).

RESULTS

In total, 816 persons with an age between 6-87 years were surveyed. In general, 22% of the male and 20% of the female recreational downhill skiers reported the use of medication. In the age group >40 years, half of the respondents were taking medication on a regular basis. 30% of males and 16% of females reported to consume alcohol on the skiing day whereas more than 50% drank alcohol on the evening before skiing the next day. 63% of those under medication concomitantly consumed alcohol.

CONCLUSIONS

The findings confirm a high prevalence of medication use and alcohol consumption in recreational downhill skiers. Even more importantly, 63% of skiers under medication concomitantly consumed alcohol. Considering the fact that only a small amount of alcohol can already affect motor and cognitive skills, it may be strongly assumed that the risk for skiing injuries is increased with alcohol consumption. Side effects of simultaneous intake of drugs and alcohol may include hypotension, vertigo and collapse which are thought to be associated with increased risks of skiing falls and injuries.

Association between speeding and use of alcohol and medicinal and illegal drugs and involvement in road traffic crashes among motor vehicle drivers

OBJECTIVE

The objective of this study was to study the association between self-reported road traffic crashes (RTCs) and recent use of alcohol and medicinal and illicit drug use and self-reported speeding in the previous 2 years.

METHODS

During the period from April 2016 to April 2017, drivers of cars, vans, motorcycles, and mopeds were stopped in a Norwegian roadside survey performed in collaboration with the police. Participation was voluntary and anonymous. The drivers were asked to deliver an oral fluid sample (mixed saliva), which was analyzed for alcohol and 39 illicit and medicinal drugs and metabolites. In addition, data on age, sex, and self-reported speeding tickets and RTCs during the previous 2 years were collected.

RESULTS

A total of 5,031 participants were included in the study, and 4.9% tested positive for the use of one or more illicit or medicinal drugs or alcohol. We found a significant, positive association between the use of cannabis and RTC involvement (odds ratio [OR] = 1.93; 95% confidence interval [CI], 1.05-3.57; P = 0.035) and also between previous speeding tickets and RTC involvement (OR = 1.39; 95% CI, 1.08-1.80; P = 0.012). In addition, older age groups were found to have a significant, negative association with RTC involvement, with ORs equal to or less than 0.49, when using the age group 16-24 as reference.

CONCLUSION

Speeding, as an indicator of risk behavior, and the use of cannabis were associated with previous RTC involvement, whereas increasing age was significantly associated with lower risk. This is consistent with previous studies on RTCs.

The prevalence of alcohol and illicit drug use among injured patients presenting to the emergency department of a national hospital in Tanzania: a prospective cohort study

BACKGROUND

Alcohol and illicit drugs have been found to be major contributing factors leading to severe injuries in a variety of settings. In Tanzania, the use of these substances among injured patients has not been studied. We investigated the prevalence of positive tests for alcohol and illicit drug use among injured patients presenting to the emergency medicine department (ED) of Muhimbili National Hospital (MNH).

METHODS

This was a prospective cohort study of a consecutive sample of patients > 18 years of age presenting to the ED-MNH with injury related complaints in October and November 2015. A structured data sheet was used to record demographic information, mechanism of injury, clinical presentation, alcohol and illicit drug test results, and ED disposition. Alcohol levels and illicit drug use were tested by breathalyser device or swab stick alcohol test and multidrug urine panel, respectively. Patients were followed up for 24 h and 30 days using medical chart reviews and phone calls. Descriptive statistics and relative risk were used to describe the results.

RESULTS

We screened 1011 patients and we enrolled all 143 (14.1%) patients who met inclusion criteria. 123 (86.0%) were male, the median age was 30 years (IQR: 23-36 years). The most frequent mechanism of injury was road traffic accidents (84.6%). 67/143 (46.9%) patients tested positive for alcohol and 44/122 (36.1%) patients tested positive for drugs. 29 (26.1%) tested positive for alcohol and drugs. The most frequently detected illicit drug was marijuana in 30/122 (24.5%) injured patients. 23/53 (43.4%) patients with positive alcohol testing self-reported alcohol use. 3/25 patients with positive illicit drug tests who were able to provide self-reports, self-reported drug use. At 30-day followup, 43 (64.2%) injured patients who tested positive for alcohol had undergone major surgery, 6 (9.0%) had died, and 36 (53.7%) had not yet returned to their baseline.

CONCLUSIONS

The prevalence of alcohol and illicit drugs is very high in patients presenting to the ED-MNH with injury. Further studies are needed to generalise the results in Tanzania. Public health initiatives to decrease drinking and/or illicit drug use and driving should be implemented.

Risk-taking propensity and (un)healthy behavior in Germany

BACKGROUND

Earlier research in South Africa (Szrek et al., 2012) confirmed the one-item Dohmen measure (Dohmen et al., 2011) to be a significant predictor of risky health behavior.

METHODS

The present study investigated the relationship of the Dohmen measure with other measures of risk-taking propensity (e.g., Domain-Specific Risk-Taking scale), and its predictive power for smoking, problematic drinking, problematic car driving, and problematic sexual behavior, in a sample of 63 patients of psychiatric clinics and 102 healthy participants in Germany.

RESULTS

The Dohmen measure was significantly positively related to other involved instruments. It served as predictor of two of the four investigated risky health activities (i.e., smoking, problematic drinking).

CONCLUSIONS

The Dohmen measure seems to be a valid and time efficient instrument to assess general risk-taking propensity, as well as specific propensity for smoking and problematic drinking in Germany.

Driving under the influence of alcohol and drugs in the eastern part of Denmark in 2015 and 2016: Abuse patterns and trends

OBJECTIVES

The objective of this study was to examine the frequency of psychoactive drugs and alcohol in drivers under suspicion of driving under the influence of drugs and alcohol in 2015 and 2016 in the eastern part of Denmark. The trends in the number of traffic cases sent for drug analysis since 2000 and alcohol analysis since 2011 are also discussed.

METHODS

Blood samples from drivers suspected of being under the influence of alcohol and/or medication and/or illicit drugs in 2015 and 2016 were investigated as requested by the police. The blood samples were screened for alcohol and/or tetrahydrocannabinol (THC) alone, for other drugs (covering all drugs, except THC, listed in the Danish list of narcotic drugs), or for THC and other drugs. Age and gender were also recorded. The number of drug traffic cases since 2000 and the number of alcohol cases since 2011 were extracted from our Laboratory Information Management System (LIMS).

RESULTS

In total, 11,493 traffic cases were investigated. Alcohol and/or drugs exceeded the legal limit in 9,657 (84%) cases. Men constituted 95% of the drivers investigated for drugs and 88% of the alcohol cases. The drivers investigated for drugs consisted primarily of young men, whereas drivers investigated for alcohol were older. The frequency was higher for positive alcohol cases above the legal limit (87%) than for drug cases (76%) above the fixed concentration limit. THC (67-69%) was the most frequently detected drug above the legal limit, followed by cocaine (27-28.5%), amphetamine (17%), and clonazepam (6-7%) in both years. Morphine (5.4%), included among the 5 most frequent drugs in 2015, was replaced by methadone (4.6%) in 2016. Few new psychoactive drugs (NPS) were detected. The number of traffic cases sent for drug analysis has increased more than 30-fold since 2000-2006, and the number of traffic cases submitted in 2016 for drug analysis was higher than the number for alcohol analysis; the latter has decreased since 2011.

CONCLUSION

Overall, alcohol was the most frequent compound detected above the legal limit in both years, followed by the well-known illicit drugs THC, cocaine, and amphetamine. NPS were seldom seen. One consequence of the increased focus on drugs in traffic has been an immense increase in drug traffic cases sent for analysis since 2006 in the eastern part of Denmark. Although this survey revealed only minimal changes compared to earlier investigations, surveys like this are invaluable for monitoring abuse patterns and trends in drugged and drunken driving.

The significance of preexisting medical conditions, alcohol/drug use and suicidal behavior for drivers in fatal motor vehicle crashes: a retrospective autopsy study

Driver fatalities in motor vehicle collisions (MVCs) encompass accidents, suicides, and natural deaths when driving. The objective of this study was to determine the significance of pathology and other autopsy findings for drivers in fatal MVCs. Forensic autopsy records of driver fatalities in southeast Norway between 2000 and 2014 were studied retrospectively. Data from individual police and collision investigation reports were also collected and analyzed. In 406 driver fatalities, the male/female ratio was 340/66; 9% died from natural causes, 9% were suicides, 65% were culpable accidental deaths, 14% were nonculpable deaths, and 3% were undetermined deaths. Head injuries and thoracic injuries were the most common causes of death. A seatbelt had been worn in 50% of the fatalities, and its prevalence did not differ between accidental deaths and suicides. Blood levels of alcohol and/or drugs that indicated impairment at the time of the collision were found in 40% (105/262) of all culpable accidental deaths but in 50% (64/127) of drivers aged up to 35 years. Pathology (most often cardiovascular disease) suggestive of sudden incapacitation before the collision was present in 24% (62/264) of drivers who were culpable in the accident and in 70% (46/66) of culpable drivers older than 55 years. A substantial proportion of drivers are killed in accidental collisions that may have occurred as a result of either alcohol/drug impairment or preexisting disease. Suicides and natural deaths both constitute significant proportions of MVC fatalities and may be misclassified unless a full inquest including an autopsy is performed.

Impact of Trauma, Massive Blood Loss and Administration of Resuscitation Fluids on a Person's Blood-Alcohol Concentration and Rate of Ethanol Metabolism

Excessive drinking and drunkenness are tightly linked to many types of intentional and unintentional injuries involving trauma and blood loss, which often necessitate emergency medical intervention. This article considers the impact of trauma, massive blood loss, and the administration of life-saving replacement fluids on a person's blood alcohol concentration (BAC) and rate of ethanol metabolism. Both German and English language journals were reviewed and results from animal experiments, human studies, and actual victims of trauma undergoing life-saving treatment were considered. If trauma-related bleeding occurs when some ingested alcohol remains unabsorbed in the stomach, then under these circumstances continued absorption into portal venous blood is delayed, owing to altered splanchnic circulation. Hemodilution caused by administration of replacement fluids has only minimal effects on a preexisting BAC, because ethanol distributes into the total body water (TBW) compartment, which represents 50-60% of body weight. After hypovolemia there is a transfer of fluids from tissue compartments into the blood, which becomes more like plasma in composition with lower hematocrit and hemoglobin content. Unless the trauma or emergency treatment impedes hepatic blood flow, the rate of ethanol metabolism is not expected to differ from normal values, namely 0.10-0.25 g/L/h (0.01-0.025 g% per h). If ethanol is fully absorbed and distributed in all body fluids and tissues, neither massive blood loss nor administration of resuscitating fluids is expected to have any significant effect on a preexisting BAC or the rate of ethanol metabolism.

Evaluation of measures of impairment in real and simulated driving: Results from a randomized, placebo-controlled study

OBJECTIVE

Standard deviation of lateral position (SDLP) is often the primary outcome in experimental studies on impaired driving. However, other measures may be easier and more practical to obtain and reflect a broader range of driving-related behaviors. We wanted to assess the validity and sensitivity of a range of measures in a driving simulator as well as during real driving and compare these to SDLP.

METHODS

Twenty healthy male volunteers undertook 6 driving trials each, 3 in a regular car on a closed track resembling rural road conditions and 3 in a simulator with an identical driving scenario. Ethanol was used as impairing substance due to its well-characterized effects on driving. The subjects were tested sober and at blood alcohol concentrations (BAC) of approximately 0.5 and 0.9 g/L. We explored dose-response relationships between BAC and a range of driving-related measures, as well as their BAC-dependent effect sizes.

RESULTS

In simulator driving, ethanol intake increased steering wheel reversal frequency, steering wheel movement measures, average speed, standard deviation of speed, and pedal use frequency. At the test track, only steering wheel movement and standard deviation of speed were significantly correlated to BAC. Likewise, reaction to unexpected incidents and observance of red traffic lights were adversely affected by ethanol in the simulator but not at the test track. Whereas SDLP showed a relatively large effect size that was similar in simulated and real driving, all other measures demonstrated smaller effect sizes, with less pronounced BAC effects on the test track than in the simulator.

CONCLUSIONS

The results suggest that the driving-related measures explored in this study are less sensitive to alcohol-mediated driving impairment than SDLP, especially during real (test track) driving. The discrepancy in effect sizes between simulated and real driving may imply low external validity of these measures in simulator studies.

Prevalence of alcohol and drugs among motorcycle riders killed in road crashes in Norway during 2001-2010

The aim of the study was to examine the prevalence of alcohol and drugs in blood samples from motorcycle riders who died in road crashes in Norway from 2001 to 2010. An additional aim was to compare the prevalence of alcohol and drugs in blood samples from fatally injured motorcycle riders and car drivers who died during the same time period. Blood samples from motorcycle riders who died within 24h after the accident (n=207, 63% of all killed riders), were analysed for alcohol, psychoactive drugs (medicinal and illicit drugs). The cut-off concentrations for alcohol and drugs findings in blood samples (i.e., the drug concentrations above which a finding was regarded as positive) were set according to the legislative limits under the Norwegian Road Traffic Act. Results were assessed in relation to age, sex, time of the day and week, and single versus multiple-vehicle accidents. Alcohol or drugs were found in 27.1 percent of all investigated riders. For riders killed in single or multiple-vehicle accidents, alcohol or drugs were found in 44.6 and 15.3 percent, respectively. Alcohol was the most frequently found substance for all age groups and most prevalent in samples from riders below 25 years who died in single-vehicle accidents (45.8 percent). Drugs were most often found among riders between 25 and 34 years (19.6 percent in total and 25.9% for those killed in single-vehicle crashes). The prevalence of alcohol or drugs was highest among riders killed in single-vehicle accidents during weekend days and nights (60.9 and 65.2 percent). Alcohol and drugs were less often found in samples from killed motorcycles riders than in samples from car and van drivers (40.2 percent). For single-vehicle accidents, the total prevalence of alcohol or drugs among killed motorcycles riders and car drivers was 44.6 percent and 63.8 percent, respectively. The same pattern of alcohol and drugs was found among the two groups, except that the prevalence among motorcycle riders was lower compared to car drivers in all age groups and time periods, which may be related to the fact that they are more vulnerable for fatal injury compared to car drivers in similar accidents.

Associations between driving under the influence of alcohol or drugs, speeding and seatbelt use among fatally injured car drivers in Norway

Since 2005, all fatal road traffic crashes in Norway have been analyzed in-depth by multidisciplinary investigation teams organized by the Norwegian Public Roads Administration (NPRA). During the period 2005-2010, 608 drivers of cars or vans were killed in road traffic crashes. Blood samples were collected from 372 (61%) of the drivers and analyzed for alcohol and a large number of psychoactive drugs at the Norwegian Institute of Public Health (NIPH). After coupling the analytical results with the NPRA crash database, 369 drivers with a fatal outcome were identified and included. Alcohol or drug concentrations in blood above the legal limits were found in 39.8% of the drivers who were investigated for alcohol or drug impairment; 33.9% had blood alcohol concentrations above 0.5g/L or concentrations of drugs above the equivalent Norwegian legal impairment limits or concentrations of amphetamines above 200μg/L. Among drivers with a fatal outcome who had been impaired by alcohol or drugs, 64.6% were unbelted and 71.7% were speeding when the crash occurred; whereas 24.2% and 33.2% of the sober drivers were unbelted or speeding, respectively. Statistically significant associations were found between impairment by alcohol or amphetamines and driving unbelted or speeding. Excessive speeding is one of the main reasons for road traffic crashes and together with being unbelted the main reasons for a fatal outcome. This behavior might in many cases be due to increased risk-taking or negligence of safety measures as a result of alcohol or drug use.