Drink driving and traffic accidents in young people

The relationship between drink driving behaviours and rates of traffic accidents was analysed in a birth cohort of 907 New Zealand young people studied to the age of 21. Drink driving was significantly (P<0.0001) related to active traffic accidents in which the driver’s behaviour contributed to the accident but was not related to passive accidents in which driver behaviours did not contribute to the accident (P>0.15). Those engaging in high rates of drink driving had rates of active traffic accidents that were 2.6 times higher than those who did not drink and drive. Further analysis suggested that much of this association was explained by confounding factors (and notably driver behaviour) that were associated with both drink driving and accident rates. After adjustment for confounding factors, those engaging in high rates of drink driving had rates of active accidents that were 1.5 (P<0.01) times higher than those who did not drink and drive. It is concluded that although the study findings support the view that the regulation of drink driving behaviour amongst young people is likely to contribute to a reduction in traffic accidents, to be fully effective attempts at regulation of drink driving also need to be accompanied by a similar level of investment in regulating other aspects of risky or illegal driving behaviour amongst young people.     

Identifying factors that predict persistent driving after drinking,unsafe driving after drinking,and driving after using cannabis among young adults

The main aim of this study was to identify adolescent/young adulthood factors that predicted persistent driving after drinking, persistent unsafe driving after drinking, and persistent cannabis use and driving among young adults. It was a longitudinal study of a birth cohort (n=933, 474 males and 459 females) and was based on data collected at ages 15, 18, 21 and 26 years. At each of these ages members of the cohort attended the research unit for a personal interview by a trained interviewer, using a standardised questionnaire. For this study, the data for the outcome measures (persistent driving after drinking, persistent unsafe driving after drinking, and persistent driving after using cannabis) were obtained at ages 21 and 26 years. The main explanatory measures were collected at ages 15, 18, 21 years and included demographic factors (academic qualifications, employment, parenting); personality measures; mental health measures (substance use, cannabis dependence, alcohol dependence, depression); anti-social behaviour (juvenile arrest, aggressive behaviour, court convictions); early driving behaviour and experiences (car and motorcycle licences, traffic crashes).The analyses were conducted by gender. The results showed that females who persisted in driving after drinking (13%, n=61) were more likely than the others to have a motorcycle licence at 18. The males who persisted in driving after drinking (28%, n=135) were more likely than the other males to have some school academic qualifications and to be employed at age 26. Compared to the other males, those who persisted in unsafe driving after drinking (4%, n=17) were more likely to be aggressive at 18 and alcohol dependent at 21. Only six (1%) females persisted in unsafe driving after drinking so regression analyses were not conducted for this group. For persistent driving after using cannabis, the univariate analyses showed that females who persisted with this behaviour tended to have high substance use at 18, cannabis dependence at 21, police contact as a juvenile, and to be a parent at 21. For this group, because of the small numbers (3%, n=13) multivariate analyses were not appropriate. For the males who persisted in driving after using cannabis (14%, n=68) a wide range of variables were significant at the univariate stage. The multivariate analysis showed that the most important factors were dependence on cannabis at 21, at least one traffic conviction before 21, a non traffic conviction before 18, and low constraint at 18. CONCLUSION: These results show different characteristics were associated with persistence in each of these outcome behaviours. This indicates that different approaches would be required if intervention programmes were to be developed to target these behaviours.     

Is driving under the influence of cannabis becoming a greater risk to driver safety than drink driving? Findings from a longitudinal study

The present study examined the associations driving under the influence of (a) cannabis and (b) alcohol, and motor vehicle collisions during, in a longitudinal study of a New Zealand birth cohort (n=936). Participants reported significantly (p<.0001) greater rates of driving under the influence of cannabis than driving under the influence of alcohol during ages 21-25. Also, there were statistically significant bivariate associations between increasing levels of both: (a) driving under the influence of cannabis and (b) self-reported driving under the influence of alcohol, and increased risks of active motor vehicle collisions (p<.0001). These associations were adjusted for potentially confounding factors including average distance driven and self-reported risky driving behaviours. After adjustment, the associations between driving under the influence of cannabis and motor vehicle collisions remained marginally significant (p=.064), whereas adjustment for confounding factors reduced the association between driving under the influence of alcohol and motor vehicle collisions to statistical non-significance (p>.70). The results of the present study suggest that, for some populations, the risks of driving under the influence of cannabis may now be greater than the risks of driving under the influence of alcohol.     

A study of driver experience and vehicle familiarity in accidents

A separate study was performed as part of a major accident investigation project to (1) test the hypothesis that drivers of vehicles involved in investigated accidents had less driving experience than the general driving population, and (2) test the hypothesis that accident involved drivers were less familiar with their vehicles than the general driving population. A Kolmogorov-Smirnov one-tail test was employed to evaluate the differences in the distributions of driver experience and vehicle familiarity between the “accident sample” and a “control sample.” Results indicated that drivers involved in the investigated accidents had less driving experience in general and had less driving experience with the accident vehicles than drivers in the general population. These effects are discussed briefly and further studies are suggested.     

Novice drivers' accidents and violations--a failure on higher or lower hierarchical levels of driving behaviour

The study compared accident and offence rates of 28 500 novice drivers in Finland. The purpose was to study differences in accident and offence rates between male and female novice drivers of different age. The drivers reported in a mailed questionnaire, how many accidents they had been involved in and how much they had driven during their whole driving career. All the drivers had a driving experience of 6–18 months. Information about offences for a 2-year period was obtained from an official register of drivers' licences. The drivers were classified into three age brackets: 18–20, 21–30 and 31–50 years. The effect of driving experience was controlled by dividing the drivers into different mileage brackets. The data was analysed and the results were discussed in the framework of the hierarchical model of driving behaviour. Young novice drivers and especially young male drivers showed more problems connected to the higher hierarchical levels of driving behaviour than middle-aged novice drivers. The number of accidents and offences was highest among the young males and their accidents took place more often at night than female or older drivers' accidents. Female drivers showed more problems connected to the lower hierarchical levels of driving behaviour, e.g. problems in vehicle handling skills. Ways of measuring accident risk of different driver groups were also discussed, as well as the usefulness and reliability of self-reports in accident studies.     

Annual mileage, driving violations, and accident involvement in relation to drivers' sex, age, and level of education.

The paper presents results of some analyses on a Dutch database that contains disaggregated data on both the traffic system input variables of the driver population (characteristics of drivers, including their annual mileage) and the output variables of the driver population in terms of habitual driving behaviour (operationalised in number of fines) and accident involvement. Accidents increased as annual mileage increased. A relationship between violations and accidents turned out to exist in different classes of annual mileage. Moreover, multivariate analyses showed that--corrected for annual mileage--male and female drivers do not differ in accident involvement; younger drivers have the highest rate of accidents and level of education is not related to accident involvement.     

Voluntary risk taking and skill deficits in young driver accidents in the UK

In absolute terms, young drivers have three to four times as many accidents per year as older drivers; and even allowing for their relative numbers in the population, their accident involvement is about 2.5 times higher than older drivers. A sample of 3437 accident reports was considered, including 1296 in detail, from midland police forces in the UK, involving drivers aged 17-25, and covering the years 1994-1996 inclusive. Four types of accident were identified as being of particular concern due to their high frequency: 'cross-flow'-turns; rear-end shunts; loss of control on bends; and accidents in darkness. (The term 'cross-flow' is used in relation to turns to denote an intersection accident where a driver is turning across the path of oncoming traffic, i.e., left turns in the US and continental Europe, but right turns in the UK and other countries where driving on the left side of the road is the norm.) An examination of driver risk taking behaviours as revealed in police interviews gave an insight into some of the motivational factors underlying young driver behaviour. Young driver accidents of all types are found to be frequently the result of 'risk taking' factors as opposed to 'skill deficit' factors. It had previously been thought that one of the main problems that young drivers have is in the area of specific skills needed in the driving task. However, it appears that a large percentage of their accidents are purely the result of two or three failures resulting from voluntary risk taking behaviour, rather than skill deficits per se. It is shown that specific groups of young drivers can even be considered as above average in driving skills, but simultaneously have a higher accident involvement due to their voluntary decisions to take risks.     

Identifying predictors of persistent non-alcohol or drug-related risky driving behaviours among a cohort of young adults

This study sought to identify adolescent risk factors that predicted persistent risky driving behaviours among young adults. It was part of a longitudinal study of a birth cohort (474 males and 459 females). The potential predictors were self-reported data obtained at ages 15, 18, 21 years (academic qualifications, personality, mental health, anti-social behaviour and driving behaviour). The risky driving behaviour outcomes were obtained at ages 21 and 26 years and included driving fast for thrills, taking deliberate risks for fun, excessive speed, dangerous overtaking, and close following (tailgating). Persistent risky drivers were defined as those who often, or fairly often engaged in a behaviour at both ages. A minority of males and very few females were classified as persistent risky drivers. Among the males, the factors that predicted at least one, or more of the outcomes were the personality trait of low constraint (i.e. low scores for control, harm avoidance, and traditionalism), aggressive behaviour, and cannabis dependence. These are characteristics to be borne in mind when developing programmes for young drivers that aim to deter the development of persistent risky driving behaviour.     

基于驾驶模拟实验的驾驶员气质与驾驶行为关系研究

目的本文研究驾驶员气质差异与驾驶行为之间的关系。方法随机抽取21名驾驶员参与驾驶模拟实验,获取受试者的气质与驾驶行为数据,再利用统计分析软件对实验数据进行统计分析。结果不同气质类型驾驶员的驾驶行为存在着明显的差异,胆汁质驾驶员的操纵行为安全性较差,有事故倾向性特征;粘液质驾驶员的操纵行为安全性较好,是四类驾驶员中最适合做驾驶员的气质类型。结论通过驾驶员气质测评可以预测驾驶员的驾驶操纵行为,评价驾驶员的安全驾驶水平,可为驾驶员的甄选、培训提供一定的依据。     

Personality and behavioral predictors of traffic accidents: testing a contextual mediated model

A contextual mediated model was proposed to distinguish the distal (i.e. personality factors) and proximal (i.e. aberrant driving behaviors) factors in predicting traffic accident involvement. Turkish professional drivers (N=295) answered a questionnaire including various measures of personality factors, driver behaviors, and accident history. Results of the latent variable analysis with LISREL indicated that latent variables in the distal context (i.e. psychological symptoms, sensation seeking, and aggression) predicted at least one of the proximal elements (i.e. aberrant behaviors, dysfunctional drinking, and preferred speed) with relatively high path coefficients. While aberrant driver behaviors yielded a direct effect on accident involvement, psychological symptoms yielded an indirect effect mediated by driver behaviors. Further analyses revealed that personality factors had an impact on road accidents via their effects on actual driving-related behaviors although the path coefficients in predicting accidents were relatively weaker than those predicting risky driving behaviors and habits. Results were discussed considering the implications for classifying the accident correlates in a contextual framework and binominal-poisson distribution of self-reported accidents.     

The traffic behaviour of elderly male automobile drivers in Gothenburg,Sweden

406 drivers over 60 years of age with automobile licences issued in Gothenburg, Sweden, were asked by a questionnaire about their driving habits in 1971. 126 drivers around 40 years of age have constituted a comparison group. A large proportion of the older drivers declared that they no longer drove their cars. More than half the number of drivers over 75 years of age and a quarter of the drivers between 65 and 69 years of age had given up driving voluntarily because of age and illness. Self-selection thus seems to be one of several factors of great importance when judging the traffic safety risks of elderly drivers. The annual distance driven by the older driver groups was shorter than in the younger age-group. The older drivers used their cars for other purposes than younger drivers and they also avoided driving in darkness, on icy roads, and in unknown cities to a far greater extent than younger drivers. The total number of accidents and offences during the older drivers' whole life-span as drivers was lower than the corresponding figures in the younger age-group. In our opinion this may depend on the shorter annual distance driven by the older drivers, the change in traffic density in the investigation area, but also to a great extent on the older drivers awareness of their reduced capacity. Their accident and offence rate during a three-year-period is quite similar to the rate in the comparison group.     

Has the difference in accident patterns between male and female drivers changed between 1984 and 2000?

The motorcar accident pattern of culpable young (18-25 years old) and middle-aged (35-55 years old) male and female drivers was studied in Finland. The aim was to see whether the difference in accident patterns between males and females has remained constant or whether it has changed over a 16-year period. Two different sets of traffic accident data were used. The first set of data covered all motorcar accidents for which damages were paid between 1987 and 2000, a total of 140802 accidents. The second set of data covered all fatal motor vehicle accidents in Finland during the time period between 1984 and 2000, a total of 2401 accidents. The results are analysed and discussed in the framework of a four-level hierarchical model of driving behaviour [Keskinen, E., 1996. Why do young drivers have more accidents? In: Junge, F., Fahrerinnen (Eds.), Young Drivers (in German and in English). Berichte der Bundesanstalt für Strabetaenwesen, Mensch und Sicherheit, Heft M 52, Bergisch Gladbach, Germany; Hatakka, M., Keskinen, E., Gregersen, N.P., Glad, A., Hernetkoski, K., 2002. From control of the vehicle to personal self-control; broadening the perspectives to driver education. Transportation Res. Part F 5 (3), 201-215]. Female drivers had proportionally more accidents that were connected to vehicle manoeuvring and control of traffic situations, e.g. reversing and loss-of-control accidents in a sober state and when not speeding. Male drivers, and especially young male drivers, had proportionally more accidents connected to higher levels of driving behaviour like motives for driving and attitudes. Factors that characterised these accidents were speeding and alcohol consumption. Male drivers also had previous traffic offences more often than female drivers. The study concludes that the difference in accident patterns between male and female drivers has remained constant, i.e. the accident pattern of female drivers was as dissimilar to the accident pattern of male drivers in the year 2000 as in the middle of the 1980s.     

Looked-but-failed-to-see-errors in traffic

Danish studies of traffic accidents at priority intersections have shown a particular type of accidents. In these accidents a car driver supposed to give way has collided with a bicycle rider on the priority road. Often the involved car drivers have maintained that they did not see the bicycle until immediately before the collision even though the bicycle must have been clearly visible.

Similar types of accidents have been the subject of studies elsewhere. In literature they are labelled “looked-but-failed-to-see”, because it seems clear that in many cases the car drivers have actually been looking in the direction where the other parties were but have not seen (i.e. perceived the presence of) the other road user. This paper describes two studies approaching this problem.

One study is based on 10 self-reported near accidents. It does show that “looked-but-failed-to-see” events do occur, especially for well experienced drivers. The other study based on Gap Acceptance shows that the car driver acceptance of gaps towards cyclists depends on whether or not another car is present. Hypotheses for driver perception and for accident countermeasures are discussed.     

Driver celeration behaviour and accidents – an analysis

A theory of changes in speed of a vehicle (termed ‘celerations’) as an overall measure of driver behaviour regarding the control of the vehicle, and as a predictor of traffic accidents, is described. The driver behaviours that result in speed changes of vehicles are speed, close following, braking and steering control actions. Assuming that all speed change indicates risk, several testable predictions follow. The most important of these is that there is a positive association between drivers’ celeration sum and their accidents. Formulas for the measurement of celeration and the association with crashes are presented, as well as methodological principles for this. Relevant literature is reviewed, as well as the tests of various hypotheses undertaken so far. The suggested way of measuring driver behaviour and predicting accident involvement would be useful in many kinds of studies of driver behaviour, and also for testing and screening purposes and especially for large-scale monitoring of professional drivers.     

Fatal traffic accidents among trailer truck drivers and accident causes as viewed by other truck drivers

Causality factors, the responsibility of the driver and driver fatigue-related factors were studied in fatal two-vehicle accidents where a trailer truck driver was involved during the period of 1991-1997 (n = 337). In addition, 251 long-haul truck drivers were surveyed in order to study their views regarding contributing factors in accidents involving trucks and the development of possible countermeasure against driver fatigue. Trailer truck drivers were principally responsible for 16% of all the accidents. Younger driver age and driving during evening hours were significant predictors of being principally responsible. In addition, the probability of being principally responsible for the accident increased by a factor of over three if the driver had a chronic illness. Prolonged driving preceding the accident, accident history or traffic offence history did not have a significant effect. Only 2% of the drivers were estimated to have fallen asleep while driving just prior to the accident, and altogether 4% of the drivers had been tired prior to the accident. Of the drivers 13% had however, been driving over 10 h preceding the accident (which has been criminally punishably in Finland since 1995 under the EC regulation) but no individual factors had a significant effect in predicting prolonged driving. The surveyed views regarding causes of truck accidents correspond well with the accident analysis. Accidents were viewed as being most often caused by other road users and driver fatigue was viewed to be no more than the fifth (out of eight) common cause of accidents. The probability of viewing fatigue as a more common cause increased significantly if the driver had experienced fatigue-related problems while driving. However, nearly half of the surveyed truck drivers expressed a negative view towards developing a technological countermeasure against driver fatigue. The negative view was not related to personal experiences of fatigue-related problems while driving.     

Characteristics of rear-end accidents at signalized intersections using multiple logistic regression model

Multi-vehicle rear-end accidents constitute a substantial portion of the accidents occurring at signalized intersections. To examine the accident characteristics, this study utilized the 2001 Florida traffic accident data to investigate the accident propensity for different vehicle roles (striking or struck) that are involved in the accidents and identify the significant risk factors related to the traffic environment, the driver characteristics, and the vehicle types. The Quasi-induced exposure concept and the multiple logistic regression technique are used to perform this analysis. The results showed that seven road environment factors (number of lanes, divided/undivided highway, accident time, road surface condition, highway character, urban/rural, and speed limit), five factors related to striking role (vehicle type, driver age, alcohol/drug use, driver residence, and gender), and four factors related to struck role (vehicle type, driver age, driver residence, and gender) are significantly associated with the risk of rear-end accidents. Furthermore, the logistic regression technique confirmed several significant interaction effects between those risk factors.     

Young driver accidents in the UK: the influence of age, experience, and time of day

Young drivers, especially males, have relatively more accidents than other drivers. Young driver accidents also have somewhat different characteristics to those of other drivers; they include single vehicle accidents involving loss of control; excess speed for conditions; accidents during darkness; accidents on single carriageway rural roads; and accidents while making cross-flow turns (i.e. turning right in the UK, equivalent to a left turn in the US and continental Europe). A sample of over 3000 accident cases was considered from midland British police forces, involving drivers aged 17-25 years, and covering a two year period. Four types of accident were analysed: right-turns; rear-end shunts; loss of control on curves; and accidents in darkness. Loss of control on curves and accidents in darkness were found to be a particular problem for younger drivers. It was found that cross-flow turn accidents showed the quickest improvement with increasing driver experience, whereas accidents occurring in darkness with no street lighting showed the slowest rate of improvement. 'Time of day' analyses suggested that the problems of accidents in darkness are not a matter of visibility, but a consequence of the way young drivers use the roads at night. There appears to be a large number of accidents associated with voluntary risk-taking behaviours of young drivers in 'recreational' driving.     

Epidemiology of traffic accidents in a Swedish municipality

Total population injury surveillance was done in an area with a population of over 41,000. All traffic accidents (N = 632) occurring within a 12-month period and requiring medical care were noted, giving a ratio of 15.3 per 1,000. They involved cyclists (38.3%), pillion passengers on cycles (1.9%), pedestrians (29.3%), motorcar drivers (7.8%), motorcar passengers (3.6%), passengers entering or leaving a vehicle (7.3%), mopedists (6.8%), motorcyclists (3.5%), and “others” (1.6%). Children and teenagers predominated in the cycle group; 55% of the males were aged 0–15 years compared with 41% of the females. Women were involved in 65% of the pedestrian accidents; 69% were aged 50 years or more. Of the accidents involving women aged over 50 years, 61% occurred in icy or snowy conditions. The police statistics were incomplete and accounted for only 23% of the total number of people reported injured by the health authorities. In some respects, the accident pattern in the present study differed from that in other comparable studies. The difference is especially great concerning the incidence of traffic accidents, the proportion of young persons involved in cycle accidents, and the number of accidents caused by motorcar drivers who developed sudden illness whilst driving.     

Driver age, car mass and accident exposure— A synthesis of available data

The tendency of younger drivers to be more likely than older drivers to drive smaller cars has been an important consideration in a number of prior investigations of the relation between car size and traffic safety. The purpose of the present study is to quantify this effect on a firmer basis than hitherto by fitting data from seven independent sources to a unified general model. More specifically, when the exposure measures “per unit distance of travel” or “per registered car” are used in studies of car mass effects on traffic safety, the exposure information often does not contain the variable driver age. This work develops a general procedure for disaggregating such exposure data into three driver (or owner) age categories; A₁: 16–24; A₂: 25–34; and A₃: 35 years. Data from the seven sources are fined to the equation

f(i,m) = H_i[1 + G _i(m/900 − 1)]

where m is the ear mass in kg, and f(i,m) is the fraction of cars of mass m which are driven (owned) by persons in the A_i, (i = 1, 2, 3) age category. The form of this equation permits easy comparison of 900 and 1800 kg cars. Those particular masses that have been chosen for illustrative comparisons in earlier work. The seven sets of data are used to derive overall average values of the parameters H₁ and G₁. The data from all seven sources show consistent effects which are summarized in one analytical expression which is well suited for use in future studies of car size effects because it reflects a synthesis of much prior data and it permits sensitivity analyses to be performed conveniently.