The involvement of drugs in drivers of motor vehicles killed in Australian road traffic crashes

A multi-center case-control study was conducted on 3398 fatally-injured drivers to assess the effect of alcohol and drug use on the likelihood of them being culpable. Crashes investigated were from three Australian states (Victoria, New South Wales and Western Australia). The control group of drug- and alcohol-free drivers comprised 50.1% of the study population. A previously validated method of responsibility analysis was used to classify drivers as either culpable or non-culpable. Cases in which the driver "contributed" to the crash (n=188) were excluded. Logistic regression was used to examine the association of key attributes such as age, gender, type of crash and drug use on the likelihood of culpability. Drivers positive to psychotropic drugs were significantly more likely to be culpable than drug-free drivers. Drivers with Delta(9)-tetrahydrocannabinol (THC) in their blood had a significantly higher likelihood of being culpable than drug-free drivers (odds ratio (OR) 2.7, 95% CI 1.02-7.0). For drivers with blood THC concentrations of 5 ng/ml or higher the odds ratio was greater and more statistically significant (OR 6.6, 95% CI 1.5-28.0). The estimated odds ratio is greater than that for drivers with a blood alcohol concentration (BAC) of 0.10-0.15% (OR 3.7, 95% CI 1.5-9.1). A significantly stronger positive association with culpability was seen with drivers positive to THC and with BAC > or =0.05% compared with BAC > or =0.05 alone (OR 2.9, 95% CI 1.1-7.7). Strong associations were also seen for stimulants, particularly in truck drivers. There were non-significant, weakly positive associations of opiates and benzodiazepines with culpability. Drivers positive to any psychoactive drug were significantly more likely to be culpable (OR 1.8, 95% CI 1.3-2.4). Gender differences were not significant, but differences were apparent with age. Drivers showing the highest culpability rates were in the under 25 and over 65 age groups.     

Analysis of factors associated with injury severity in crashes involving young New Zealand drivers

Young people are a risk to themselves and other road users, as motor vehicle crashes are the leading cause of their death. A thorough understanding of the most important factors associated with injury severity in crashes involving young drivers is important for designing well-targeted restrictive measures within youth-oriented road safety programs. The current study estimates discrete choice models of injury severity of crashes involving young drivers conditional on these crashes having occurred. The analysis examined a comprehensive set of single-vehicle and two-vehicle crashes involving at least one 15–24 year-old driver in New Zealand between 2002 and 2011 that resulted in minor, serious or fatal injuries. A mixed logit model accounting for heterogeneity and heteroscedasticity in the propensity to injury severity outcomes and for correlation between serious and fatal injuries proved a better fit than a binary and a generalized ordered logit. Results show that the young drivers’ behavior, the presence of passengers and the involvement of vulnerable road users were the most relevant factors associated with higher injury severity in both single-vehicle and two-vehicle crashes. Seatbelt non-use, inexperience and alcohol use were the deadliest behavioral factors in single-vehicle crashes, while fatigue, reckless driving and seatbelt non-use were the deadliest factors in two-vehicle crashes. The presence of passengers in the young drivers’ vehicle, and in particular a combination of males and females, dramatically increased the probability of serious and fatal injuries. The involvement of vulnerable road users, in particular on rural highways and open roads, considerably amplified the probability of higher crash injury severity.     

Costs of alcohol-related crashes: New Zealand estimates and suggested measures for use internationally

This paper presents policy-oriented measures of alcohol-related crash incidence and costs in New Zealand (N.Z.). Costs of crashes, where alcohol probably was a contributing factor were computed from official crash costs and police-reported crash/injury counts adjusted for under-reporting of crashes and of alcohol involvement. Alcohol-related crashes cost an estimated $1.2 billion in N.Z. in 1996. They equate to an estimated $0.75 per drink consumed, $17.80 per km driven above the legal limit of 0.08, and $1100 per heavy drinker. People other than the drinkers, who caused the crashes, paid half the costs. An estimated one in 90 drunk-driving trips resulted in a crash (and often a drunk driving conviction) while one in 375 crash-free drunk driving trips also resulted in a drunk-driving conviction. Ten measures of alcohol-related crash incidence and costs are recommended for international use. They include number of alcohol-related deaths and injuries; innocent victims and children harmed in crashes caused by drinkers; annual costs and costs paid by people other than the drinker who caused the crash; crash costs per drink consumed, per heavy drinker, per kilometer driven drunk versus sober; probabilities of crash and of drunk-driving conviction.     

Characteristics of traffic crashes in Maryland (1996-1998): differences among the youngest drivers

Motor vehicle crashes (MVCs) are the leading cause of death among teenagers in the US. The present study examines how crash rates and crash characteristics differed among drivers aged 16-21 in the state of Maryland from 1996 to 1998. The results show that, based on police reports. the youngest drivers have the highest rate of MVCs per licensed driver and per annual miles driven. Furthermore, crash characteristics suggest that inexperience rather than risky driving may account for the differing rates. Drivers closer to the age of 16 had their crashes under the safest conditions: during the day in clear weather while drinking less.     

The influence of driver distraction on the severity of injuries sustained by teenage drivers and their passengers

Studies show that teenage drivers are at a higher risk for crashes. Opportunities to engage in technology and non-technology based distractions appear to be a particular concern among this age group. An ordered logit model was developed to predict the likelihood of a severe injury for these drivers and their passenger using a national crash database (the 2003, U.S. DOT-General Estimate System [GES]). As one would expect, speeding substantially increases the likelihood of severe injuries for teenage drivers and their passengers. The results of the analysis also reveal that teenage drivers have an increased likelihood of more severe injuries if distracted by a cell phone or by passengers than if the source of distraction was related to in-vehicle devices or if the driver was inattentive. Additionally, passengers of teenage drivers are more likely to sustain severe injuries when their driver is distracted by devices or passengers than with a non-distracted or inattentive driver. This supports the previous literature on teenage drivers and extends our understanding of injuries for this age group related to distraction-related crashes.     

The influence of road curvature on fatal crashes in New Zealand

Bends in roads can cause crashes but a recent study in the UK found that areas with mostly curved roads had lower crash rates than areas with straighter roads. This present study aimed to replicate the previous research in a different country. Variations in the number of fatal road crashes occurring between 1996 and 2005 in 73 territorial local authorities across New Zealand were modelled against possible predictors. The predictors were traffic flow, population counts and characteristics, car use, socio-economic deprivation, climate, altitude and road characteristics including four measures of average road curvature. The best predictors of the number of fatal crashes on urban roads, rural state highways and other rural roads were traffic flow, speed limitation and socio-economic deprivation. Holding significant factors constant, there was no evidence that TLAs with the most curved roads had more crashes than elsewhere. Fatal crashes on urban roads were significantly and negatively related to two measures of road curvature: the ratio of road length to straight distance and the cumulative angle turned per kilometre. Weaker negative associations on rural state highways could have occurred by chance. These results offer limited support to the suggestion that frequently occurring road bends might be protective.     

Declines in fatal crashes of older drivers: changes in crash risk and survivability

Objectives

Previous research has found that older driver fatal crash involvement rates per licensed driver declined substantially in the United States during 1997–2006 and declined much faster than the rate for middle-age drivers. The current study examined whether the larger-than-expected decline for older drivers extended to nonfatal crashes and whether the decline in fatal crash risk reflects lower likelihood of crashing or an improvement in survivability of the crashes that occur.

Methods

Trends in the rates of passenger vehicle crash involvements per 100,000 licensed drivers for drivers 70 and older (older drivers) were compared with trends for drivers ages 35–54 (middle-age drivers). Fatal crash information was obtained from the Fatality Analysis Reporting System for years 1997–2008, and nonfatal crash information was obtained from 13 states with good reporting information for years 1997–2005. Analysis of covariance models compared trends in annual crash rates for older drivers relative to rates for middle-age drivers. Differences in crash survivability were measured in terms of the odds of fatality given a crash each year, and the historical trends for older versus middle-age drivers were compared.

Results

Fatal crash involvement rates declined for older and middle-age drivers during 1997–2008 (1997–2005 for the 13 state subsample), but the decline for drivers 70 and older far exceeded the decline for drivers ages 35–54 (37 versus 23 percent, nationally; 22 versus 1 percent, 13 states). Nonfatal injury crash involvement rates showed similarly larger-than-expected declines for older drivers in the 13 state subsample, but the differences were smaller and not statistically significant (27 percent reduction for older drivers versus 16 percent for middle-age drivers). Property-damage-only crash involvement rates declined for older drivers (10 percent) but increased for middle-age drivers (1 percent). In 1997, older drivers were 3.5 times more likely than middle-age drivers to die in police-reported crashes (6.2 versus 1.8 deaths per 1000 crashes), but this difference was reduced during the 9-year study period to 2.9 times, as the rate of older drivers dying in a crash declined (5.5 deaths per 1000 crashes in 2005) and the death risk remained relatively stable for middle-age drivers.

Conclusions

Contrary to expectations based on increased licensure and travel by older drivers, their fatal crash risk has declined during the past decade and has declined at a faster rate than for middle-age drivers. The decreased risk for older drivers appears to extend not only to nonfatal injury crashes but also to property-damage-only crashes, at least as reported to police in the 13 states included in the nonfatal injury analysis. Although insurance collision data suggest that overall crash risk of older drivers may not be changing relative to middle-age drivers, the current analysis indicates that the reduced fatality risk of older drivers reflects both less likelihood of being involved in a police-reported crash and greater likelihood that they will survive when they do crash.     

The roles of exposure and speed in road safety analysis

Speed is a determining factor in road safety analysis. It is generally believed that an increase in speed harms road safety. However, it can also be argued that driving at high speed reduces the length of time exposure and thus the likelihood of a crash. It is therefore critical to clarify the roles that exposure and speed play in road safety analysis. This study evaluates the relationship between speed and crash risk with respect to distance and time exposure, using disaggregated crash and speed data collected from 112 road segments in Hong Kong. A joint probability model based on a full Bayesian method is applied simultaneously to model crash occurrence and crash severity. In addition, we consider the explanatory variables, including road design, weather conditions, and temporal distribution, in the proposed crash prediction model. The results indicate that average speed plays a significant role in crash risk, despite opposing correlations with respect to distance and time exposure; the correlation between speed and crash risk is positive when distance exposure is considered, but negative when time exposure is used. However, in both cases, speed is positively associated with the injury severity.     

The effects of vehicle model and driver behavior on risk

We study the dependence of risk on vehicle type and especially on vehicle model. Here, risk is measured by the number of driver fatalities per year per million vehicles registered. We analyze both the risk to the drivers of each vehicle model and the risk the vehicle model imposes on drivers of other vehicles with which it crashes. The "combined risk" associated with each vehicle model is simply the sum of the risk-to-drivers in all kinds of crashes and the risk-to-drivers-of-other-vehicles in two-vehicle crashes. We find that most car models are as safe to their drivers as most sport utility vehicles (SUVs); the increased risk of a rollover in a SUV roughly balances the higher risk for cars that collide with SUVs and pickup trucks. We find that SUVs and to a greater extent pickup trucks, impose much greater risks than cars on drivers of other vehicles; and these risks increase with increasing pickup size. The higher aggressivity of SUVs and pickups makes their combined risk higher than that of almost all cars. Effects of light truck design on their risk are revealed by the analysis of specific models: new unibody (or "crossover") SUVs appear, in preliminary analysis, to have much lower risks than the most popular truck-based SUVs. Much has been made in the past about the high risk of low-mass cars in certain kinds of collisions. We find there are other plausible explanations for this pattern of risk, which suggests that mass may not be fundamental to safety. While not conclusive, this is potentially important because improvement in fuel economy is a major goal for designers of new vehicles. We find that accounting for the most risky drivers, young males and the elderly, does not change our general results. Similarly, we find with California data that the high risk of rural driving and the high level of rural driving by pickups does not increase the risk-to-drivers of pickups relative to that for cars. However, other more subtle differences in drivers and the driving environment by vehicle type may affect our results.     

Odds of fault and factors for out-of-state drivers in crashes in four states of the USA

Drivers outside their country of residence are at a safety disadvantage when compared to native counterparts. This research aimed to (1) investigate if out-of-state drivers in the United States experienced the same vulnerabilities as foreign drivers, and (2) examine the relations of out-of-state crashes to various human and environmental factors. Crash data from Florida, Maine, Minnesota, and Nevada was analyzed to model fault using logistic regressions. Univariate regressions showed that out-of-state drivers had increased odds of fault, ranging from 17% to 92%, for a single-vehicle crash compared to in-state drivers in all states except Florida, where there was no difference between groups. Odds were elevated for out-of-state drivers in two-vehicle crashes by 3% to 19% in all states except Florida and Minnesota, where, again, there was no difference between groups. Human and environmental factors such as age, sex, driving conditions, and seasons were examined with multivariate regressions for in- and out-of-state groups separately, and their odds ratios were compared. For single-vehicle crashes age, sex, road grade, surface condition, light conditions, and day of week were factors that increased at least one of the two groups’ odds of fault in all states. Sex, surface condition, and light conditions increased the odds of fault for at least one of the groups in two-vehicle crashes in all four states. Factors that consistently increased odds of fault for both single- and two-vehicle crashes were males, non-vehicle owners, curves, and inclement weather. Although there were several factors in each state that increased odds of fault for out-of-state drivers, no factors consistently increased odds of fault for out-of-state drivers across all four states.     

Analysis of injury severity of drivers involved in single- and two-vehicle crashes on highways in Ontario

This study analyzes driver's injury severity in single- and two-vehicle crashes and compares the effects of explanatory variables among various types of crashes. The study identified factors affecting injury severity and their effects on severity levels using 5-year crash records for provincial highways in Ontario, Canada. Considering heteroscedasticity in the effects of explanatory variables on injury severity, the heteroscedastic ordered logit (HOL) models were developed for single- and two-vehicle crashes separately. The results of the models show that there exists heteroscedasticity for young drivers (≤30), safety equipment and ejection in the single-vehicle crash model, and female drivers, safety equipment and head-on collision in the two-vehicle crash models. The results also show that young car drivers have opposite effects between single-car and car–car crashes, and sideswipe crashes have opposite effects between car–car and truck–truck crashes. The study demonstrates that separate HOL models for single-vehicle and different types of two-vehicle crashes can identify differential effects of factors on driver's injury severity.     

Spatial analysis of fatal and injury crashes in Pennsylvania

Using injury and fatal crash data for Pennsylvania for 1996-2000, full Bayes (FB) hierarchical models (with spatial and temporal effects and space-time interactions) are compared to traditional negative binomial (NB) estimates of annual county-level crash frequency. Covariates include socio-demographics, weather conditions, transportation infrastructure and amount of travel. FB hierarchical models are generally consistent with the NB estimates. Counties with a higher percentage of the population under poverty level, higher percentage of their population in age groups 0-14, 15-24, and over 64 and those with increased road mileage and road density have significantly increased crash risk. Total precipitation is significant and positive in the NB models, but not significant with FB. Spatial correlation, time trend, and space-time interactions are significant in the FB injury crash models. County-level FB models reveal the existence of spatial correlation in crash data and provide a mechanism to quantify, and reduce the effect of, this correlation. Addressing spatial correlation is likely to be even more important in road segment and intersection-level crash models, where spatial correlation is likely to be even more pronounced.     

Distribution and characteristics of road traffic crashes in the Chaoyang District of Beijing, China

In many developing urban settings, economic growth and motorization are coupled with increasing rates of road traffic injuries (RTIs). By highlighting typical sites and circumstances at/in which car crashes occur, more specific targets for prevention can be identified. The study is based on police data for a 1-year period and covers the Chaoyang District, the biggest district of Beijing City. Focus is placed on crash patterns and their distribution by types of road and areas. Both fatal and non-fatal crashes are considered (n=754). In the main, the crashes occurred in relatively favorable driving circumstances (e.g., sunny weather, flat and straight roads, asphalted roads, and good traffic signals and road markings). They were also quite evenly distributed over time of day, day of week and season. Five crash patterns were highlighted, of which three were strongly associated with specific areas and four with specific types of road. The study supports the idea that type of road and RTI severity or pattern are closely related. It contributes to the development of context-relevant prevention measures aimed at reducing road crashes and minimizing their consequences and also supports safe planning of the road traffic environment.     

The use of videos in road safety training: Cognitive and emotional effects

The aim of the study was to evaluate the use of videos in educational programs for improving road safety. Particularly, we evaluated the cognitive and emotional effects of viewing videos taken from cameras placed along Italian highways and showing car crashes or traffic flow images.     

An exploratory study of the relationship between road rage and crash experience in a representative sample of US drivers

The phenomenon of road rage has been frequently discussed but infrequently examined. Using a representative sample of 1382 US adult drivers, who were interviewed in a 1998 telephone survey, exploratory analyses examined the relationship between self-reported measures of road rage, generally hazardous driving behaviors, and crash experience. Regarding specific road rage behaviors, most respondents reported having engaged in verbal expressions of annoyance; however only 2.45% reported ever having been involved in direct confrontation with another car or driver. After controlling for gender, age. driving frequency, annual miles driven and verbal expression, an angry/threatening driving subscale of road rage was significantly associated with hazardous driving behaviors that included frequency of driving over the legal blood alcohol limit, receipt of tickets in the past year. and habitually exceeding the speed limit as well as crash experience. However, the verbal/frustration expression subscale was not associated with crash experience or hazardous driving indicators, except for number of tickets, after controlling for other crash-related factors such as gender and age. Direct confrontation by deliberately hitting another car or leaving the car to argue with and/or injure another driver was rarely reported. Results suggest that angry/threatening driving is related to crash involvement; however, after controlling for exposure and angry/threatening and hazardous driving the relationship of milder expressions of frustration while driving and crash involvement was not significant.     

The prevalence of alcohol, cannabinoids, benzodiazepines and stimulants amongst injured drivers and their role in driver culpability: part ii: the relationship between drug prevalence and drug concentration, and driver culpability

Blood samples from 2,500 injured drivers were analysed for alcohol, cannabinoids (measured by the presence of THC), benzodiazepines and stimulants. The relationship between the prevalence and concentration of drugs and the culpability of the driver was examined using an objective method for assessing culpability. There were no significant differences between males and females with respect to culpability. However, there was a relationship between age and culpability: drivers under 26 years and over 60 years were more likely to be culpable. Drivers who tested positive for alcohol only, benzodiazepines only and the combinations of alcohol and THC and alcohol and benzodiazepines were significantly more likely to be culpable for the crash compared with the drug-free group. Conversely, a lower percentage of drivers who only tested positive for THC were culpable for the crash compared with drug-free drivers. This difference was not statistically significant. For car drivers in single-vehicle crashes, the majority of drivers were judged culpable irrespective of drug use. In multiple-vehicle crashes, car drivers testing positive for alcohol only or benzodiazepines only were more likely to be culpable for the crash compared with drug-free drivers. For motorcycle riders in both single- and multiple-vehicle crashes, there were no significant differences between the drug-positive and drug-free groups. A higher percentage of drug-free riders in multiple-vehicle crashes were culpable compared with riders who only tested positive for THC, but this difference was not statistically significant. There was a significant concentration-dependent relationship between alcohol and culpability: as blood alcohol concentration increased, so did the percentage of culpable drivers. When THC was used alone, there was no significant increase in culpability. For those drivers with benzodiazepines at therapeutic concentrations and above, there was a significant increase in culpability. The relationship between stimulants and culpability was not significant, although a higher proportion of stimulant-positive drivers were culpable compared with drug-free drivers. The combinations of alcohol and THC, and alcohol and benzodiazepines also produced a significant increase in culpability, but this increase was not significantly greater than that produced by alcohol alone.     

Personality subtypes of young moped drivers, their relationship to risk-taking behavior and involvement in road crashes in an Austrian sample

Objective

This study aimed to identify subtypes of young moped drivers and analyze how these subtypes are involved in risk preferences and road crashes.

Design

A group of Austrian teenage moped drivers (213, 28% girls) completed an online questionnaire about moped usage, injuries, driving style, inattention, impulsivity, and personality according to the Five-Factor Model of Personality and Cloninger's model of personality.

Results

A cluster analysis yielded four types of moped drivers. One type was characterized by a high level of neuroticism, the second type was characterized by a risky personality and a risky driving style, the third type had a more cautious driving style, and the fourth type was characterized by a risky personality and high levels on inattention and impulsivity.

Conclusions

Our conclusions suggest that young moped drivers should not be perceived as a homogenous group, according to measures of injury prevention and intervention.     

The prevalence of alcohol, cannabinoids, benzodiazepines and stimulants amongst injured drivers and their role in driver culpability: part i: the prevalence of drug use in drive the drug-positive group

Blood samples from 2,500 injured drivers were analysed for alcohol, cannabinnoids, benzodiazepines and stimulants. Overall, three-quarters of drivers tested negative for drugs. Alcohol was the most frequently detected drug. Cannabinoids were also detected at high rates, but the majority of drivers tested positive for THC-acid, the inactive metabolite of THC. Benzodiazepines and stimulants were detected at low rates, and detection rates for combinations of drugs were also low. Males were more likely to test positive for drugs, especially alcohol and THC, whereas females were more likely to test positive for benzodiazepines. A similar proportion of car drivers and motorcycle riders tested positive for drugs, although riders were more likely to test positive for THC. Single-vehicle crashes were particularly associated with alcohol for both car driver and riders, and for riders, multiple-vehicle crashes were particularly associated with THC.