Predicting at-fault car accidents of older drivers

Considerable research shows car accidents are difficult to predict using screening tests. The objective of this exploratory study is to determine whether detailed accident analysis taking into account the specific accident type might enhance the predictive power of a standardised road test and a set of selected neuropsychological tests. Moreover, this study addresses the validity and reliability of performance-based driving evaluation. The sample consisted of 84 older drivers between 65 and 96 years of age who were referred for a fitness-to-drive evaluation. Using discriminant analyses, the subjects were classified as drivers with and without at-fault accidents. We compared the accuracy of neuropsychological tests and a road test for postdicting all accidents, accidents classified into two categories and accidents classified into four different categories. The percentages of correctly classified subject were highest at the level of the most detailed classification. These results suggest that, although accident prediction is difficult, the predictability of car accidents by neurocognitive measurements and a road test increases when the kind of accident is specified.     

Predicting the number of accidents at a road junction

We consider a model, within a Bayesian framework, which can be used to predict the number of accidents occurring at a road junction in a given period of time. The predictions are based on measurements of the traffic flows as well as on covariates which describe important features of the junctions. Various approximate and estimative methods, which use Gibbs sampling, posterior normality and Laplace approximations, are considered and compared. Procedures to assess the importance of the different covariates through the use of the Kullback-Leibler measure of divergence are also developed.     

An assessment of seasonal and weather effects on the frequency of road accidents in California

The day-to-day variations in the numbers of accidents on the State Highways of California in 1970 have been studied with reference to the time of year and the weather type. The weather was found to be a major factor affecting accident numbers. The mean number per day was 353 and the overall variance 11158. The variance was reduced by over 70% when 23 wet days, Christmas Eve and Christmas Day were excluded. On very wet days the number of accidents was often double that of corresponding dry days. Single-vehicle accidents were affected more by wet weather than were most other types of accident studied.     

Analysis of climbing accidents

The fall of a climber is analyzed by realistic and comprehensive model calculations. Various parameters that define such a fall and the action of the belaying system to stop it are included in an equation describing the balance between the energy gained by the fall and the various channels of dissipation. The result is a representative overview about the interplay between the various parameters. From this understanding, important consequences and recommendations for safety in climbing are deduced.     

Timber-concrete-composite with an adhesive connector (wet on wet process)

In timber-concrete-composite structures the connection is traditionally achieved with mechanical means. The Swiss adhesive producer SIKA has developed a special adhesive which is capable of bonding the concrete both wet and hardened. Within the framework of the project, the wet process was investigated. The first project phase was concerned with the possible displacement of the adhesive when the fresh concrete is poured onto the wet adhesive. Key parameters such as the concrete type and the falling height of the concrete were analysed. After the adhesive had been freshly applied onto the wood, a certain time interval was allowed for the adhesive to stiffen before the concrete was poured: this “stiffening time” also proved to be a key parameter. After the production parameters had been optimised, a number of timber-concrete-composite slabs were cast and tested in bending. The test results fully met the expectations.     

Previous convictions or accidents and the risk of subsequent accidents of older drivers

The over-involvement of elderly drivers in collisions has a potentially adverse effect on highway safety. The question for most experts in traffic research is whether we can predict the individual risk of accidents and which variables are the best predictors, especially for this population. For a better understanding of the elderly drivers' problems, this study aimed to describe the most common types of accidents in the elderly population of drivers living in Quebec (> or = 65 years of age). The second objective of the study was to analyse the relationship between previous accidents or convictions and the risk of subsequent accidents. The results show that: (1) elderly drivers are characterised by error accidents involving more than one car, especially at intersections, (2) prior accidents are a better predictor for accident risk than prior convictions and (3) these trends steadily increase with each age group (drivers 65 years old to 80 years or more). The results are discussed in relation to the literature on risk behaviour of the elderly drivers.     

Wind-induced accidents of road vehicles

This paper describes the results of a project that collected and collated data for windinduced vehicle accidents that occurred in the United Kingdom during the major storm of 25 January 1990. The results of this data analysis are used to determine which vehicles are most at risk during windy periods, the nature of the accidents that were caused, and the likely values of accident wind speeds. Also the adequacy of a computer program that can predict such wind speeds (the program BLOWOVER) is assessed as far as the available data allows.     

Societal influences on childhood accidents

Efforts aimed at the prevention of accidents to children have, at various times, focused on the behavior of the child, the behavior of the child's parents, and the physical environment of the child. Whatever their focus, many of these efforts have been unsuccessful because they have failed to take into account social factors which influence not only the behavior of both children and parents but also the nature and number of hazards in the child's environment, both at home and elsewhere. This paper reviews briefly each of the several foci of accident countermeasures in order to identify social factors that have been overlooked and to indicate why these factors must be recognized and dealt with if future countermeasures are to be effective.     

Alcohol use and motorcycle accidents

An investigation of 1508 of the 1577 fatal and injury producing motorcycle accidents reported to Victoria police during 1974 revealed that alcohol usage was a significant factor. A similar result was indicated by five other Australian studies which report on post-mortem examinations of fatally injured motorcycle riders. Alcohol affected riders were significantly over represented in fatal and single vehicle accidents. The majority of killed riders had blood alcohol levels typical of problem drinkers. Motorcycle riders had similar blood alcohol levels to a comparable group of drinking car drivers but a significantly lower proportion of killed motorcycle riders were affected by alcohol than killed car drivers. Motorcycle riders affected by alcohol were mainly younger than twenty-five years of age, but this was probably due to the youthfulness of the motorcycle riding population.     

Motorcycle conspicuity and traffic accidents

An analysis of data from 1508 motorcycle accidents obtained from Victoria Police files for the year 1974 indicates that inadequate motorcycle visibility is an associated factor in 64.5% of automobile/motorcycle collisions. It is the sole identifiable cause of 21.0% of collisions. The conspicuity of the front of the motorcycle is found to be vitally important in these accidents.     

Modeling accidents for prioritizing prevention

The Workgroup Occupational Risk Model (WORM) project in the Netherlands is developing a comprehensive set of scenarios to cover the full range of occupational accidents. The objective is to support companies in their risk analysis and prioritization of prevention. This paper describes how the modeling has developed through projects in the chemical industry, to this one in general industry and how this is planned to develop further in the future to model risk prevention in air transport. The core modeling technique is based on the bowtie, with addition of more explicit modeling of the barriers needed for risk control, the tasks needed to ensure provision, use, monitoring and maintenance of the barriers, and the management resources and tasks required to ensure that these barrier life cycle tasks are carried out effectively. The modeling is moving from a static notion of barriers which can fail, to seeing risk control dynamically as (fallible) means for staying within a safe envelope. The paper shows how concepts develop slowly over a series of projects as a core team works continuously together. It concludes with some results of the WORM project and some indications of how the modeling is raising fundamental questions about the conceptualization of system safety, which need future resolution.     

The science of space weather

The basic physics underpinning space weather is reviewed, beginning with a brief overview of the main causes of variability in the near-Earth space environment. Although many plasma phenomena contribute to space weather, one of the most important is magnetic reconnection, and recent cutting edge research in this field is reviewed. We then place this research in context by discussing a number of specific types of space weather in more detail. As society inexorably increases its dependence on space, the necessity of predicting and mitigating space weather will become ever more acute. This requires a deep understanding of the complexities inherent in the plasmas that fill space and has prompted the development of a new generation of scientific space missions at the international level.     

Physical aspects of wet granulation III. effect of wet granulation on granule porosity

The porosity of granules produced by wet granulation has been studied using mercury porosimetry. Granule pore size distribution appears to be bimodal, with a population of micropores and macropores. Pore surface area varies with kneading time, going through a maxima at a point where physical properties such as flow and bulk density also exhibit a maxima. True granule density displays a direct relationship to rate of flow. The information in general supports the postulate that equilibrium microporous granules are formed first in the wet granulation process, followed by consolidation with subsequent formation of microporous twins and agglomerates.