Modeling traffic accident occurrence and involvement

The Negative Binomial modeling technique was used to model the frequency of accident occurrence and involvement. Accident data over a period of 3 years, accounting for 1,606 accidents on a principal arterial in Central Florida, were used to estimate the model. The model illustrated the significance of the Annual Average Daily Traffic (AADT), degree of horizontal curvature, lane, shoulder and median widths, urban/rural, and the section's length, on the frequency of accident occurrence. Several Negative Binomial models of the frequency of accident involvement were also developed to account for the demographic characteristics of the driver (age and gender). The results showed that heavy traffic volume, speeding, narrow lane width, larger number of lanes, urban roadway sections, narrow shoulder width and reduced median width increase the likelihood for accident involvement. Subsequent elasticity computations identified the relative importance of the variables included in the models. Female drivers experience more accidents than male drivers in heavy traffic volume, reduced median width, narrow lane width, and larger number of lanes. Male drivers have greater tendency to be involved in traffic accidents while speeding. The models also indicated that young and older drivers experience more accidents than middle aged drivers in heavy traffic volume, and reduced shoulder and median widths. Younger drivers have a greater tendency of being involved in accidents on roadway curves and while speeding.     

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.     

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

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

The relationship between alcoholrelated traffic fatalities and per capita consumption of alcohol, Ontario, 1957–1983

In this research, the impact of per capita consumption of alcohol on alcohol-related traffic fatalities in Ontario between 1957 and 1983 was examined. Three measures of alcohol involvement were selected. The first, drinking drivers (police reported) involved in fatal accidents, was a direct measure. The second and third, single-vehicle fatal accidents and nighttime fatal accidents, were surrogate measures. Also, three corresponding measures of fatal accidents not involving alcohol (normal drivers [police reported] involved in fatal accidents, multiple vehicle fatal accidents, and daytime fatal accidents) were chosen to control for general road safety trends. The results of regression analyses indicated that both per capita consumption and general road safety trends were significant contributors to all three measures of alcohol-involved fatalities. These and other recent data suggest that any effort to prevent alcohol-related problems such as liver cirrhosis through control of per capita consumption will also have a beneficial impact on alcohol-related accidents.     

Traffic accident rates among finnish out-patients

A questionnaire was administered to 765 rheumatoid arthritic, 715 tuberculous, and 1050 psychiatric outpatients concerning their use of alcohol and drugs, driving habits, and traffic accident involvement. The same questionnaire was administered to 587 controls. The driving populations of all groups were matched as to their age, and living district. The main finding of the study was that, as the traffic exposure was controlled, the non-drug treated patients were not involved in accidents more often than the controls. In the psychiatric out-patient group, drug use was linked with an increased accident rate. Heavy use of alcohol was linked with increased traffic exposure in the present study. The combined use of alcohol and drugs tended to increase one's involvement in accidents.     

Drugs related to motor vehicle crashes in northern European countries: A study of fatally injured drivers

The aim of this study was to find which drugs and drug combinations were most common in drivers who died, in particular, in single vehicle crashes where the responsibility for the crash would be referred to the driver killed. The study included all available blood samples from drivers, who died within 24 h of the accident, in the years 2001 and 2002 in the five Nordic countries (total population about 24 million inhabitants). The samples were analysed for more than 200 different drugs in addition to alcohol, using a similar analytical programme and cut-off limits in all countries. In three countries (Finland, Norway and Sweden) blood samples were available for more than 70% of the drivers, allowing representative prevalence data to be collected. 60% of the drivers in single vehicle crashes had alcohol and/or drug in their blood samples, compared with 30% of drivers killed in collisions with other vehicles. In single vehicle accidents, 66% of the drivers under 30 years of age had alcohol and/or drugs in their blood (alcohol only – 40%; drugs only – 12%; alcohol and drugs – 14%). The drugs found were mostly illicit drugs and psychoactive medicinal drugs with warning labels (in 57% and 58% respectively of the drivers under 30 with drugs present). Similar findings were obtained for drivers 30–49 years of age (63% with alcohol and/or drugs). In drivers aged 50 years and above, killed in single vehicle crashes (48% with alcohol and/or drugs) illicit drugs were found in only one case, and psychoactive medicinal drugs were detected less frequently than in younger age groups. In 75% of single vehicle crashes, the driver was under 50 years. Thus, the majority of accidents where the drivers must be considered responsible, occurred with drivers who had recently used alcohol, or drugs, alone or in combination. The drugs involved were often illicit and/or psychoactive drugs with warning labels. Therefore a large proportion of single vehicle accidents appear to be preventable, if more effective measures against driving after intake of alcohol and drugs can be implemented.     

Drugs related to motor vehicle crashes in northern European countries: a study of fatally injured drivers

The aim of this study was to find which drugs and drug combinations were most common in drivers who died, in particular, in single vehicle crashes where the responsibility for the crash would be referred to the driver killed. The study included all available blood samples from drivers, who died within 24 h of the accident, in the years 2001 and 2002 in the five Nordic countries (total population about 24 million inhabitants). The samples were analysed for more than 200 different drugs in addition to alcohol, using a similar analytical programme and cut-off limits in all countries. In three countries (Finland, Norway and Sweden) blood samples were available for more than 70% of the drivers, allowing representative prevalence data to be collected. 60% of the drivers in single vehicle crashes had alcohol and/or drug in their blood samples, compared with 30% of drivers killed in collisions with other vehicles. In single vehicle accidents, 66% of the drivers under 30 years of age had alcohol and/or drugs in their blood (alcohol only – 40%; drugs only – 12%; alcohol and drugs – 14%). The drugs found were mostly illicit drugs and psychoactive medicinal drugs with warning labels (in 57% and 58% respectively of the drivers under 30 with drugs present). Similar findings were obtained for drivers 30–49 years of age (63% with alcohol and/or drugs). In drivers aged 50 years and above, killed in single vehicle crashes (48% with alcohol and/or drugs) illicit drugs were found in only one case, and psychoactive medicinal drugs were detected less frequently than in younger age groups. In 75% of single vehicle crashes, the driver was under 50 years. Thus, the majority of accidents where the drivers must be considered responsible, occurred with drivers who had recently used alcohol, or drugs, alone or in combination. The drugs involved were often illicit and/or psychoactive drugs with warning labels. Therefore a large proportion of single vehicle accidents appear to be preventable, if more effective measures against driving after intake of alcohol and drugs can be implemented.     

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.     

Drug use and the severity of a traffic accident

Several studies have showed that driving under the influence of alcohol and/or certain illicit or medicinal drugs increases the risk of a (severe) crash. Data with respect to the question whether this also leads to a more severe accident are sparse. This study examines the relationship between the use of alcohol, illicit drugs and/or medicinal drugs and the severity of an accident within a group of drivers that were involved in a crash in The Netherlands. Blood samples of 993 drivers, collected in the period from October 1998 through September 1999, were linked to accident characteristics as available from the National Transport Research Centre. The outcome measure was the severity of the accident. An accident was considered severe when the accident had resulted in hospital admission or death. All the blood samples obtained after the accident were screened for the presence of alcohol, illicit drugs (opiates, amphetamines and amphetamine-like substances, cocaine and metabolites, methadone, cannabinoids) and medicinal drugs (benzodiazepines, barbiturates and tricyclic antidepressants). The strength of the associations between exposure to the different classes of alcohol/drugs/medicines and the severity of the accident was evaluated using logistic regression analysis and were expressed as odds ratios (OR), adjusted for age, gender, time of the day, day of the week and urban area. The most frequently detected drugs were cannabinoids, benzodiazepines and cocaine. Our results showed no clear association between the use of alcohol, illicit drug and/or medicinal drug use and the severity of the accident. Given the process of obtaining blood samples from drivers involved in accidents and the retrospective nature of the study, we cannot rule out the occurrence of selection bias. Therefore, our findings need further confirmation.     

Fatal accident involvement rates by driver age for large trucks

Survey data on large trucks involved in fatal accidents and on the travel of large trucks provide estimates of fatal accident involvement rates by driver age. The analysis is focused on the implications of lowering the minimum age for drivers of commercial trucks operating interstate from 21 to 19 years. Fatal accident involvement rates for drivers of large trucks are found to increase with decreasing driver age. The younger drivers are over-involved until about age 27. Drivers under the age of 21 are over-involved by a factor of 6 in comparison to the overall rate for all drivers. Other factors known to have significant influences on the probability of involvement in a fatal accident were examined to determine their association with the over-involvement of younger drivers. The general pattern of over-involvement for younger drivers pervades virtually every combination of factors examined. Thus, it is concluded that the basic trend with driver age shown in the aggregate data is primarily associated with age and is not associated with the other factors examined. The results of this analysis substantiate an elevated risk of fatal accident involvement for younger drivers of large trucks.     

The prevalence of drugs in motor vehicle accidents and traffic violations in Shanghai and neighboring cities

The objective of this study was to determine the prevalence of psychoactive drug use among motor vehicle drivers in Shanghai and its neighboring cities. We selected 10,002 drivers involved in a traffic accident or violation between 2007 and 2008 in Shanghai, Suzhou and Wuxi. We checked for the presence of psychoactive drugs from blood samples using liquid chromatography tandem mass spectrometry (LC–MS–MS). Of the 10,002 drivers, 10.5% tested positive for drugs (excluding alcohol). Cold medicines were the most frequently detected drugs including chlorpheniramine (4.78%), pseudoephedrine (2.15%) and paracetamol (1.32%). The use of multiple cold medicines was common. Illegal drugs such as methamphetamine (0.15%), ketamine (0.03%) and MDMA (0.01%) were also detected. The prevalence of psychoactive drugs among drivers involved in traffic accidents or violations in Shanghai and its neighboring cities was lower compared to previous reports in Europe. Furthermore, cannabis—which has been reported to be the most widely used psychoactive drug after alcohol—was not commonly encountered among Shanghai drivers.     

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.     

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.     

Profiling drunk driving recidivists in Denmark

Drunk drivers are a menace to themselves and to other road users, as drunk driving significantly increases the risk of involvement in road accidents and the probability of severe or fatal injuries. Although injuries and fatalities related to road accidents have decreased in recent decades, the prevalence of drunk driving among drivers killed in road accidents has remained stable, at around 25% or more during the past 10 years. Understanding drunk driving, and in particular, recidivism, is essential for designing effective countermeasures, and accordingly, the present study aims at identifying the differences between non-drunk drivers, drunk driving non-recidivists and drunk driving recidivists with respect to their demographic and socio-economic characteristics, road accident involvement and other traffic and non-traffic-related law violations. This study is based on register-data from Statistics Denmark and includes information from 2008 to 2012 for the entire population, aged 18 or older, of Denmark. The results from univariate and multivariate statistical analyses reveal a five year prevalence of 17% for drunk driving recidivism, and a significant relation between recidivism and the drunk drivers’ gender, age, income, education, receipt of an early retirement pension, household type, and residential area. Moreover, recidivists are found to have a higher involvement in alcohol-related road accidents, as well as other traffic and, in particular, non-traffic-related offences. These findings indicate that drunk driving recidivism is more likely to occur among persons who are in situations of socio-economic disadvantage and marginalisation. Thus, to increase their effectiveness, preventive measures aiming to reduce drunk driving should also address issues related to the general life situations of the drunk driving recidivists that contribute to an increased risk of drunk driving recidivism.     

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.     

Can it be true that most drivers are safer than the average driver?

Surveys finding that a large majority of drivers regard themselves as safer than the average driver have been ridiculed as showing that most drivers are overconfident about their safety and as showing something which is logically impossible, since in a normal distribution exactly half are below average and half above. This paper shows that this criticism is misplaced. Driver accident involvement does not follow a normal distribution, and it is mathematically entirely possible that a huge majority of drivers could be safer than the average driver. The distribution of accidents in a population of drivers is typically skewed, with a majority of drivers not reporting involvement in any accident in the period covered by the data, often a period of 1–3 years. In this paper, examples are given of data sets in which the percentage of drivers who are safer than the average driver ranges from about 70% to 90%. The paper explains how, based on knowing the mean and variance of the distribution of accidents in a population of drivers in a given period, the long-term expected number of accidents for drivers who were involved in 0, 1, 2, or more accidents can be estimated. Such estimates invariably show that the huge majority of drivers are safer than the average driver.     

Perception of the risk of an accident by young and older drivers

Young drivers are significantly overrepresented among all drivers involved in traffic accidents and fatalities. Excessive risk taking by young drivers appears to be largely responsible for this disproportionate involvement. This excessive risk taking could be due to being more willing to take risks than older drivers are, failing to perceive hazardous situations as being as dangerous as older drivers do or both causes. This paper reports the results of a study which attempted to determine whether misperception of risk could be an explanation for the high rates of traffic accidents among youth by testing whether young drivers perceive driving to be less hazardous than do older drivers. Three different methods of estimating the risk of accident involvement were used to compare risk estimates of young and older drivers. The methods included general questions about accident involvement, rating the riskiness of ten specific driving situations illustrated in still photographs, and rating the riskiness of fifteen videotaped driving situations. Young drivers perceived their own chances of an accident to be significantly lower than those of both their peers and older male drivers, while older male drivers saw their chances of accident involvement as comparable to those of their male peers and less than those of young male drivers. These findings lend support to the thesis that young male drivers are overrepresented in traffic accidents at least in part because they fail to perceive specific driving situations as being as risky as older drivers perceive them.     

Do accident-involved drivers exhibit riskier everyday driving behavior?

For more than forty years researchers have tried to relate traffic accident involvement to how an individual normally drives. Such efforts have not hitherto discovered clear effects. This study establishes statistically significant relations between prior involvement in accidents and an observed characteristic of every day driving. The observed driving characteristic is following headway in high flow freeway traffic, defined as the time interval between a vehicle and the preceding vehicle in the same lane. This headway is interpreted as a measure of driver risk. It is found that accident-involved drivers are more likely to follow with short headways (less than 1 s) than accident-free drivers. A similar effect is found in comparing drivers with and without traffic violations.     

Psychosocial correlates of the impact of road traffic accidents among South African drivers and passengers

The aim of the study was to investigate the psychosocial consequences and coping strategies among accident victims in South Africa. Participants (138 drivers and 141 passengers) who had been involved in a road traffic accident were approached and interviewed in public places. In both groups the median age group was between 25 years and 34 years. In 34 accidents (12.2%) a family member was killed, in 68 accidents (24.4%) a non-family member was killed in the accident. In 272 accidents 197 (72.4%) persons (both drivers and passengers) were injured and 168 (61.7%) were hospitalized. Eighty-seven drivers (63%) did not perceive themselves at fault and 51 (37%) did. Following the road traffic accident both drivers and passengers showed a significant decline of their well-being. Drivers who perceived themselves to be at fault did not cope better than those not perceiving themselves at fault. Passengers related to the drivers showed more decline in their well-being than those not related. Path analysis for drivers found that holding oneself responsible had a direct, and mediated by self-blame, guilt and family distress, negative effect on personal well-being. In the passengers group, holding the driver or others responsible led, mediated by increased self-blame, feelings of guilt, and family distress, to lower psychological well-being (PWB). Findings have relevant implications for the development of coping strategies to aid victims of road traffic accidents in dealing with their trauma in this African context, which may differ to those in Western societies.