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.     

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.     

Driver irritation and aggressive behaviour

A sample of 98 drivers responded to a Swedish version of the UK Driving Anger Scale [UK DAS; [Lajunen, T., Parker, D., Stradling, S.G., 1998. Dimensions of driver anger, aggressive and highway code violations and their mediation by safety orientation in UK drivers. Transport. Res. Part F 1, 107–121]. The results indicated that the Swedish version, like the British original, measures three sources of driver irritation: “progress impeded”, “reckless driving”, and “direct hostility”. Structural equation modelling was used to investigate the relationships between the three sources of self-reported driver irritation, aggressive actions, speed, sex, age, and annual mileage. The models suggested a positive relationship between the amount of driver irritation and frequency of aggressive actions for all three sources of irritation. Female drivers tended to become more irritated than male drivers, while the male drivers tended to act aggressively more often. Surprisingly, drivers who reported that they enjoy fast speeds did not become more irritated than slower drivers when obstructed. The important conclusions are that experienced irritation often leads to openly aggressively actions, and that expression of aggressive behaviours may be a cause of other drivers’ feeling of irritation.     

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 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.     

Limits of the quasi-induced exposure method when compared with the standard case-control design. Application to the estimation of risks associated with driving under the influence of cannabis or alcohol

The disparities between the quasi-induced exposure (QIE) method and a standard case–control approach with crash responsibility as disease of interest are studied. The 10,748 drivers who had been given compulsory cannabis and alcohol tests subsequent to involvement in a fatal crash in France between 2001 and 2003 were used to compare the two approaches. Odds ratios were assessed using conditional and unconditional logistic regressions. While both approaches found that drivers under the influence of alcohol or cannabis increased the risk of causing a fatal crash, the two approaches are not equivalent. They differ mainly with regards to the driver sample selected. The QIE method results in splitting the overall road safety issue into two sub-studies: a matched case–control study dealing with two-vehicle crashes and a case–control study dealing with single-vehicle crashes but with a specific control group. Using a specific generic term such as “QIE method” should not hide the real underlying epidemiological design. On the contrary, the standard case–control approach studies drivers involved in all type of crashes whatever the distribution of the responsibility in each crash. This method also known as “responsibility analysis” is the most relevant for assessing the overall road safety implications of a driver characteristic.     

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.     

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.     

Reductions in driver speed using posted feedback of speeding information: social comparison or implied surveillance?

Reducing driver speed has an essential role to play in traffic safety. This study measured the effect of a roadside sign, in a 50 km/h zone, that consecutively displayed one of three messages:

1. The average speed at the site: this message was designed to induce “social comparison” whereby drivers may reduce their speed in order to comply with the behaviour of the majority.

2. A warning that drivers’ speeds were being measured: this was intended to imply surveillance whereby drivers may reduce speed in order to avoid possible enforcement action.

3. A combination of both messages, to see if both together would have a greater effect than either alone.

The speed of drivers travelling along a busy urban road (11,500 cars daily in each direction) was measured using inductive loop detectors. The proportion of drivers travelling 60 km/h or less increased with all three messages, suggesting that both social comparison and implied surveillance are mechanisms by which driver speed may be reduced. However, the speed reductions were not as great as in previous studies of feedback signs. This may be due to differences in the existing safety culture.     

Risky attitudes towards road use in pre-drivers

Motor vehicle accidents are one of the principal causes of adolescent disability or mortality and male drivers are more likely to be involved in road accidents than female drivers. In part such associations between driver age and sex have been linked to differences in risky behaviour (e.g. speed, violations) and individual characteristics (e.g. sensation seeking, deviant behaviour). The aim of this research is to determine whether associations between risky road user behaviour and individual characteristics are a function of driver behaviour or whether they are intrinsic and measurable in individuals too young to drive.

Five hundred and sixty-seven pre-driver students aged 11–16 from three secondary schools completed questionnaires measuring enthusiasm for speed, sensation seeking, deviant behaviour and attitudes towards driver violations. Boys reported more risky attitudes than girls for all measures. Associations between sensation seeking, deviant behaviour and attitudes towards risky road use were present from early adolescence and were strongest around age 14, before individuals learn to drive.

Risky attitudes towards road use are associated with individual characteristics and are observed in adolescents long before they learn to drive. Safe attitudes towards road use and driver behaviour should be promoted from childhood in order to be effective.     

A different perspective on conspicuity related motorcycle crashes

The most common type of conflict in which a motorcyclist is injured or killed is a collision between a motorcycle and a car, often in priority situations. Many studies on motorcycle safety focus on the question why car drivers fail to give priority and on the poor conspicuity of motorcycles. The concept of ‘looked-but-failed-to-see’ crashes is a recurring item. On the other hand, it is not entirely unexpected that motorcycles have many conflicts with cars; there simply are so many cars on the road. This paper tries to unravel whether – acknowledging the differences in exposure – car drivers indeed fail to yield for motorcycles more often than for other cars. For this purpose we compared the causes of crashes on intersections (e.g. failing to give priority, speeding, etc.) between different crash types (car–motorcycle or car–car). In addition, we compared the crash causes of dual drivers (i.e. car drivers who also have their motorcycle licence) with regular car drivers. Our crash analysis suggests that car drivers do not fail to give priority to motorcycles relatively more often than to another car when this car/motorcycle approaches from a perpendicular angle. There is only one priority situation where motorcycles seem to be at a disadvantage compared to cars. This is when a car makes a left turn, and fails to give priority to an oncoming motorcycle. This specific crash scenario occurs more often when the oncoming vehicle is a motorcycle than when it is a car. We did not find a significant difference between dual drivers and regular car drivers in how often they give priority to motorcycles compared to cars.     

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.     

Inherent safety, ethics and human error

A patient is to have the damaged left kidney removed. To safeguard correctness of action several layers of expert checks have been performed prior to the operation, which results in the removal of the fully functional right kidney. Nobody asked the patient. The patient did not volunteer providing “unnecessary” information. The experts know everything …

An untidy house made out of flammable materials. A careless smoker left his lit cigarette unattended. A blow of wind and the house comes in flames. Would better construction materials have prevented the accident in spite of the carelessness of the inhabitant

A tricky medical condition which is expected to provoke a patient's fast health deterioration and their slow death. The doctor takes the initiative and responsibility of performing a risky operation. The patient's life is saved and their health is re-established.

This work is not, as initially intended, the result of a thorough investigation of accidents, neither contains a systematic collection of data that can support the conclusions or the suggestions made. It is in the main a compilation of personal views. These views have been established from the correlation of the results of numerous accident investigation reports with the causes of small and insignificant incidents. These incidents are related with the education of university students, regulations within an academic environment and from independent personal experience working in different countries and with people of different cultures. The analysis that follows, however, should not be perceived as a mere reference to university students and/or to a university environment. University is the place where the fundamental scientific and engineering principles are germinated while current and past university students are the future and current production and design engineers, respectively. The places where the presented incidents have occurred are not always relevant with the conclusions, thus they are not stated. The reason this article is presented here is that I believe that often, complex accidents, similarly to insignificant ones, often demonstrate an attitude which can be characterized as “inherently unsafe”. I take the view that the enormous human potential and the human ability to minimize accidents needs to become a focal point towards inherent safety. Restricting ourselves to human limitations and how we could “treat” or prevent humans from not making accidents needs to be re-addressed.

The purpose of this presentation is to highlight observations and provoke a discussion on how we could possibly improve the understanding of safety related issues. I do not intent to reject or criticize existing methodologies. (The entire presentation is strongly influenced by Trevor Kletz's work although our views are often different.)     

Speed as a measure of driver risk: Observed speeds versus driver and vehicle characteristics

This investigation was performed to determine relationships between driver and vehicle characteristics and freely chosen speeds of cars on a two lane road with little commercial or residential development. Speed is taken as a measure of a driver's willingness to expose himself to risk of accident, in the same way that short freeway headways were interpreted in an earlier study. A total of 6638 passenger car speeds were measured by radar while each oncoming vehicle was simultaneously photographed. Driver and vehicle characteristics were derived from the photographs, both by direct observation (vehicle type, driver sex, presence of front seat passengers, seat belt use) and from the car license plate through the use of State vehicle registration and driver licensing files. The State files provided the car mass and model year and the owner (usually driver) age, sex, and recorded accidents and violations. Higher speeds were observed for younger drivers, drivers with prior accidents and convictions, newer cars, heavier cars and cars with no passengers.     

Comparison groups in road safety studies: An analysis

When the safety effect of some treatment is to be estimated, one has to answer the question: “what would have been the ratio of the expected number of accidents ‘before’ and ‘after’ had the treated group been left without treatment? ” In retrospective observational studies, the count of accidents on a “comparison group” is often used to provide an answer. In consequence, the estimate of the safety effect depends on which of several comparison groups is chosen. It is therefore important to have guidance for this choice. The empirical inquiry in the companion paper led to several conclusions. The explanation of what has been noted by the examination of data requires analysis and is taken up in this paper.     

A modeling perspective on the culture of driving

Each driver is influenced by the collective behavior of other drivers. At the same time, each driver is also part of this collective, and thus influences others. Underlying many driver control and traffic safety programs are two implicit and related assumptions: that drivers are sensitive to the “culture of driving” around them and emulate it; and, that a small shift in the behavior of few might be amplified or snowball to a much larger effect resulting in a changed traffic environment or a modified culture of driving. The paper discusses possible mechanisms for the interactions between individuals, collectives, and culture, drawing on literature from social psychology, sociology, economics, communication, epidemiology, and other disciplines. Traffic behavior modeling could benefit from considering concepts developed in other social disciplines while providing challenging research issues and data sources for testing and developing those concepts.     

Hearing loss and automobile airbag deployments

In an on-going research program, on the causation of injuries in motor vehicle accidents, at the University of Michigan Transportation Research Institute, crashes with airbags have been, and are continuing to be, investigated. In order to determine the occurrence, if any, of ‘hearing problems’ associated with airbag deployments, drivers and passengers who had been involved in ‘airbag’ automobile crashes were interviewed by telephone. From the crashes investigated, 225 attempts were made to contact drivers who were exposed to airbag deployments. From these telephone interviews, contacts were made with 177 car occupants. Only three reported that they had experienced any type of hearing-related problems subsequent to their crash. One other case is reported of a driver who had pre-crash hearing loss. It appears that permanent hearing deficit due to airbag deployment, both in cars with the steering wheel airbag alone, and in those with a passenger side airbag, is an infrequent event (1.7%) from the data of this study.