Multiple-vehicle traffic accidents in Hong Kong

‘Multiple-vehicle traffic accident’ refers to a crash between two or more moving objects. Unlike single-vehicle accidents, not all drivers involving in a multiple-vehicle accident are responsible for the occurrence of the event. Accordingly, variables such as road type, speed limit and number of vehicles involved in the accident are expected to play a much more important role in association with injury severity in multiple-vehicle accidents. To study the factors influencing injury severity of multiple-vehicle traffic accidents, a population-based study was conducted. The traffic accident data was obtained from the Traffic Accident Data System (TRADS), which was developed by the Transport Department, Police Force and Information Technology Services Department, Hong Kong. Multiple-vehicle traffic accidents (N = 10,630) occurring during the 2-year period 1999/2000 were considered. Potential risk factors such as district, human, vehicle, safety, environmental and site factors were examined. Categorizing injury severity into “fatal/serious” and “slight”, a stepwise logistic regression model was applied to the population data set. The district board, time of the accident, driver's gender, vehicle type, road type, speed limit and the number of vehicles involved are significant factors influencing the injury severity. Identification of risk factors for severe traffic accidents provides valuable information to help with new and improved road safety control measures.     

Using traffic conviction correlates to identify high accident-risk drivers

One of the primary missions of the California Department of Motor Vehicles is to protect the public from drivers who represent unacceptably high accident risks. Optimum fulfillment of this objective requires the development and implementation of strategies for identifying high-risk drivers. One such system in California is the department’s negligent operator point system. This system assigns points to moving violations and accidents and authorizes the department to take driver control actions against drivers who meet the prima facie definition of a negligent operator. The present study explored the viability of predicting accidents from equations constructed to predict convictions for the general driving population. Equations or models that better identify drivers at increased risk of future accident involvement would increase the number of accidents prevented through post license control actions. Although the results did not support prior findings that equations keyed to citations do as well as or better than equations keyed to accidents in predicting subsequent accident involvement, a canonical correlation approach considering subsequent accident and citation rates simultaneously produced a 14.9% improvement in the classification accuracy or “hit rate” for identifying accident-involved drivers.     

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.     

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.     

Attitudes of commercial motor vehicle drivers towards safety belts

Despite the fact that Hawaii has one of the highest seat belt use rates for passenger vehicles in the United States, and has had a mandatory seat belt use law since the 1980s, studies have shown that commercial motor vehicles (CMV) seat belt use rates are low. To better understand this phenomenon, a comprehensive survey of commercial vehicle drivers was conducted in Hawaii to ascertain attitudes and self-reported behaviors regarding seat belt use. A total of 791 drivers responded to a written questionnaire implemented at weigh stations and distributed to various trucking firms and transport centers. Approximately 67% reported that they use seat belts “always” when driving a CMV (commercial motor vehicle), yet when asked how often do other CMV drivers use seat belts, only 31% responded “always.” Interestingly, 86% of these same drivers reported that they use seat belts “always” when driving a personal vehicle. The major reason cited for non-use of belts was “frequent stops/inconvenience” (29%), and “not safety conscious” (23%). Notably, the self-reported use of safety belts is highest among operators of vans (88% said “always”), followed by buses (87% said “always”) and lowest among truck drivers (only 60% said “always”). In this paper, some of the differences between self-reported users and non-users are explored and a multivariate logit model was developed to predict the odds of belt use as a function of various factors.     

Factors associated with automobile accidents and survival

This paper develops an econometric model for vehicles' inherent mortality rate and estimates the probability of accidents and survival in the United States. Logistic regression model is used to estimate probability of survival, and censored regression model is used to estimate probability of accidents. The estimation results indicated that the probability of accident and survival are influenced by the physical characteristics of the vehicles involved in the accident, and by the characteristics of the driver and the occupants. Using restrain system and riding in heavy vehicle increased the survival rate. Middle-aged drivers are less susceptible to involve in an accident, and surprisingly, female drivers are more likely to have an accident than male drivers. Riding in powerful vehicles (high horsepower) and driving late night increase the probability of accident. Overall, the driving behavior and characteristics of vehicle does matter and affects the probabilities of having a fatal accident for different types of vehicles.     

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.     

Tiredness and visual reaction time among nighttime cab drivers: A roadside survey

The present roadside survey seeks to elucidate the incidence of tiredness among nighttime cab drivers by comparing self-assessed level of tiredness with the results of a simple visual reaction test. Attempts to separate various forms of fatigue from sleepiness are not made, as it appears less important in studies of everyday traffic than in experimental investigations. One-hundred-and-twenty cab drivers of vacant cabs were stopped by the police on a major highway just outside the city of Copenhagen. Eighty drivers declared themselves rested, 38 tired, and 2 very tired. The reaction test showed considerable individual variation, but subdivision of the drivers according to level of tiredness demonstrated a statistically significant and uniform difference throughout the night (p < 0.0001). One self-assessed tired driver was reclassified to the group of very tired based on the questionnaire and reaction test. The investigation indicates that accidents due to “driver asleep” would be expected among the three (2.5%) very tired cab drivers. The questionnaire and visual reaction test turned out to be complementary in the present study and are both useful implements for future roadside surveys of tiredness in nighttime traffic.     

A prevention programme for drinking driving

A drinking-driving programme introduced in one borough of Toronto, Canada, is evaluated. Based on evidence from previous programmes judged effective, it combined a highly visible “random” spot-check enforcement component with a drinking-driving educational component. A three-wave telephone survey showed significant increases in public knowledge of drinking and driving and of the programme in the experimental area. The subjective perception of arrest risk was increased for the “average driver” but not for “myself”. Unfortunately, only indirect evidence was available on driver behaviour and this tended to indicate fewer impaired drivers on the road. Finally, police reported alcohol-related accidents and injuries indicated an overall downward trend in Toronto, but the urban nature and restricted size of the experiment's geographic unit, as well as similar changes in control areas and contaminations to the data rendered the analysis highly ambiguous. Thus, the programme experienced some positive although by no means conclusive indicators of success.     

The effects of combining sanctions and rehabilitation for driving under the influence: An evaluation of the New Jersey alcohol countermeasures program

In contrast to many other state Driving under the Influence (DUI) programs developed in the United States in the 1970s as alternatives to traditional sanctions, the New Jersey Alcohol Countermeasures Program combined sanctions with mandatory education/rehabilitation for offenders. Three components were evaluated: DUI education, “treatment,” and Alcoholics Anonymous. For 2,734 first and repeat offenders participating in this program between 1979 and 1982, the program was effective in reducing DUI recidivism for program completers (66% while licensed and 51% while suspended) compared with noncompleters, but it was less effective in reducing subsequent moving violations while licensed (20% compared with noncompleters) and accidents while licensed (18% compared with noncompleters). Completers had higher rates of violations and accidents while suspended (9% compared with noncompleters). A small group of repeat offenders, missassigned to DUI education, had higher post conviction rates of negative driving events than those of comparable offenders assigned to “treatment” or Alcoholics Anonymous, indicating that for these offenders the latter interventions were more effective.     

The relationships among driving while impaired charges, police drinking—driving roadcheck activity, media coverage and alcohol-related casualty traffic accidents

A correlational examination of 54 consecutive months of data from British Columbia on the relationships among the number of vehicles checked in police drinking-driving roadchccks, the number of driving while impaired (DWI) charges laid, the number and percent of alcohol-related casualty traffic accidents, and the extent of media coverage on drinking-driving (as measured by print media coverage), revealed that: the extent of media coverage, and not the extent of roadchecks or charging activity is probably the critical element in the reduction of drinking-driving accidents. The failure of the minimally publicized April–May 1984 British Columbia police roadcheck “blitz” to reduce either the number or proportion of alcohol-related casualty traffic accidents lent support to these correlational findings.     

A preliminary evaluation of the impact of local accident information on the public perception of road safety

The World Health Organisation (WHO) estimate that road traffic accidents represent the third leading cause of “death and disease” worldwide. A number of countries have, therefore, launched safety campaigns that have reduced their fatalities. In almost every case, however, this reduction has not been matched by a fall in the total frequency of road traffic accidents. Low-severity incidents remain a significant problem. “Attribution error” provides one plausible explanation for this phenomenon. Most drivers believe that they are less likely to be involved in an accident than other motorists. Existing road safety campaigns do little to address this problem; they focus on national and regional statistics that often seem remote from the local experiences of road users. This paper, therefore, describes the design and development of a system to provide the general public with access to information on the location and circumstances of road accidents in a Scottish city. The closing sections describe the initial results from a psychometric study that is intended to determine whether the information provided by such an application will have any impact on individual risk perception.     

A typology for drinking driving offenders: Methods for classification and policy implications

Comprehensive arrest histories were obtained for 353 DUI offenders who were referred to a probation and rehabilitation demonstration program. The average number of total offenses was 7.9, with 89% of all tracked offenders having more than one offense. Approximately 63% of all recorded offenses were other types of offenses besides DUI. The overall arrest history profile of the group suggested that many DUI offenders are habitual violators of other laws as well. To identify distinctive arrest profiles within the referral sample, a Q mode factor analysis followed by a discriminant function analysis was used to classify offenders into profile subgroups. Five distinctive subgroups emerged. A “low offense” group was characterized by the lowest average number of overall arrests and also contained all offenders with no arrest besides the index DUI arrest. A “mixed” group had a higher average number of total arrests than the “low offense” group and diverse types of offenses. A young “traffic” group was distinguished by many hazardous moving violations other than DUI. Two smaller and older groups—a “public drunkenness” group and a “license” group—had the highest average number of arrests including DUI, public drunkenness, license violations, equipment violations, disturbance arrests and assault arrests. These subgroups were found to differ on demographic variables and drinker status variables. The “public drunkenness” group was found to have the highest accident rate. Groups were compared to groups found in other cluster analyses. Also, treatment implications were discussed. It was suggested that treatment programs focusing exclusively on changing alcohol consumption behavior are not likely to reduce accident risk for some of the offender groups. For example, it was suggested that effective intervention for the “traffic” group should target driving behavior, whether drunk or sober, rather than focus exclusively on consumption behavior. Other alternatives are also discussed.     

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.     

Cannabis use and traffic accidents in a birth cohort of young adults

Objective: to examine linkages between cannabis use and traffic accident risks in a birth cohort of 907 young New Zealanders studied from 18 to 21 years. Methods: during the course of a 21-year longitudinal study of a birth cohort of 907 New Zealand born children information was gathered on (a) annual frequency of cannabis use over the period from 18 to 21 years; (b) annual rates of traffic accidents during the period 18–21 years; (c) measures of driver behaviours and characteristics. The association between cannabis use and traffic accident risk was examined among the 907 sample members who reported driving a motor vehicle between the ages of 18 and 21 years. Results: there were statistically significant relationships between reported annual cannabis use and annual accident rates. This association was present only for ‘active’ accidents in which driver behaviours contributed to the accident; those using cannabis more than 50 times per year had estimated rates of active accidents that were 1.6 (95% CI 1.2–2.0) times higher than the rate for non-users. However, statistical control for driver behaviours and characteristics related to cannabis use (drink driving behaviour; risky/illegal driving behaviours; driver attitudes; gender) eliminated the association between cannabis use and traffic accident risks. Conclusions: although cannabis use was associated with increased risks of traffic accidents among members of this birth cohort, these increased risks appear to reflect the characteristics of the young people who used cannabis rather than the effects of cannabis use on driver performance.     

On the prevention of accidents and injuries : A comparative analysis of conceptual frameworks

The meaning of prevention has changed as new applications of the concept have appeared. Ideas presented in eleven different conceptual frameworks are compared. Identification of the frameworks took place through searches in databases and relevant literature. Five are general by nature, while six relate to injuries and accidents. All are supported by just a few parameters, the time dimension being the most prominent. Compatibility was established on three additional dimensions: level (individual, organizational or societal); direction (“bottom-up” or “top-down”); and in relation to the trichotomy “host-agent-environment”. An attempt to synthesize all these dimensions into one general model of accident and injury prevention is presented.     

The optimism bias and traffic accident risk perception

Research suggests that people are excessively and unrealistically optimistic when judging their driving competency and accident risk. In this study, college-age drivers compared their risk of being involved in a variety of described traffic accidents relative to their peers. They also rated each of the accidents along a number of dimensions hypothesized as being related to optimism. In addition, subjects provided global estimates of their driving safety, skill, and accident likelihood. Significant optimism was evident for both the accidents and the global ratings. Optimism increased with driving experience and marginally with age. Those with more driving experience considered human factors to be more important in accident causation; those assigning more importance to human factors also rated themselves as more skillful drivers. For the specific accidents, perceived controllability was a strong predictor of optimism. The findings for controllability are interpreted in terms of other recent data and hypothesized explanations of the optimism bias. In general, it appears that optimism arises because people persistently overestimate the degree of control that they have over events.     

Statistical analyses of highway commercial vehicle accidentst†

In a research program aimed at the assessment of more comprehensive accident analysis methods, new applications of statistical analysis procedures to commercial vehicle accidents have been investigated, and exemplary results obtained [Philipson et al., 1978], A file of some 3000 specially-detailed California Highway Patrol accident reports from two areas of California during a period of about one year in 1975–1976 provided the unique data base for the application. Computer implementation and evaluation through statistical testing of the quality of the data file were first accomplished. Then an exhaustive univariate analysis of the data was conducted to describe the file in detail. Selected sets of dependent and independent variables were then subjected to analyses of association employing contingency table analysis methods. In several cases, acceptable log-linear models to explain the variables' association were thereby established. Vehicle exposure measured in vehicle miles traveled for each vehicle category was introduced into one of the analyses to assess its impact on the set of significant interactions; it was indeed found to be important, albeit accuracy in its estimation was problematical. This estimation was carried out by two independent methods; a “direct” procedure based on a series of linear extrapolations of basic State of California commercial vehicle traffic data, and an “induced” estimation procedure essentially employing only data in the accident reports. The results of the two methods exhibited some common trends, but otherwise differed considerably. The results of the research effort, highlighted in this article, indicated the value of the methods investigated, and so of the detailed accident report files necessary for their use. They also strongly illuminated the areas of greatest difficulty in the application of these methods, basically associated with accident data quality and exposure estimation accuracy, and general directions for their improvement.     

Commentary on statistical issues underlying the evaluation of a social policy change on motor vehicle accident involvement

This commentary addresses the statistical issues which are involved in assessing whether a causal interpretation can be given to an association between a change in social policy such as lowering the legal age for drinking alcohol and a change in the nature of accident involvement frequency for a particular sub-population of drivers like 18–20 year olds. In this regard, two methodological concerns are emphasized. The first is the resolution of a possible paradox in the nature of an association in the sense that individuals with a greater tendency to accident involvement may also have a greater tendency to alcohol usage so that their alcohol related accident involvement is coincidental rather than causal. For this setting, alcohol would be an “after the fact” correlate with accident involvement as opposed to a possible cause. Similarly, the second concern is the role of population exposure as an explanation for the change in alcohol related accident frequency for a particular age group. Since availability naturally increases the size of the population at risk for such accidents, the corresponding accident frequency may similarly increase even though the corresponding accident rates may have remained unchanged or perhaps even decreased. For these reasons, although associations with change in social policy are definitely of general interest, their interpretation in a causal sense should be viewed with substantial caution until the implications of competing explanations are reconciled. This assertion, however, does not mean that such associations are not useful for policy purposes, but rather that they lack sufficiently targeted statistical validity to be the primary basis for such change. In other words, if there is a strong rationale on economic, political, or social grounds for a policy change, then data presenting meaningful associations which are compatible with it can often play an important supportive role for it.