Accident ratios investigation

FIGURE 4.2 The updated accident ratio. (From McKinnon, Ron C. 2012. Safety Management, Near Miss Identification, Recognition and Investigation. Boca Raton Taylor Francis. With permission.)... 

The accident ratio depicted in Model 1.1 shows that for every serious injury as a result of an accident there are some minor injuries, more property damage events, and plenty of near miss incidents. The only way to reduce the injuries that make up the peak of the triangle is to identify, investigate, and rectify the near miss events before they result in injuries or other losses. 

Over the years, researchers around the world have investigated the near miss theory and have compiled numerous accident ratios. They have researched the ratio between the near miss incidents, accidents causing damage, minor injuries, and serious injuries. Most of the research has indicated that there are more near miss incidents that have no visible sign of loss than injury- or damage-producing accidents. 

The philosophy behind these various accident ratios is that by investigating and taking action to prevent near misses, the more serious accidents and incidents would be prevented. This approach could be said to be far too simplistic, in that not all near misses involve risks which might have caused fatal or serious injury. However, these ratios are of great value in comparing categories of accidents in order to identify those categories which are most likely to cause serious harm. 

Accident investigation indicates that there are often many individual causes to an accident, and that a series of incidents occur simultaneously to cause the accident. The following figure is called the safety triangle", and shows the approximate ratios of occurrence of accidents with different severities. This is based on industrial statistics. 

A drum of phosphoryl chloride, recovered by distillation, burst some ten hours after filling. The line and pump used for transfer had been cleaned with acetone, pockets of which probably remained. Calorimetry revealed that, starting at 30°C, unmixed and unstirred acetone and oxychloride (molar ratio not reported) heated slowly to 55°C over two hours and thereafter ran-away to 180° and substantial pressure in a few minutes. It was concluded that acetone was the cause of the mishap, and probably of some other incompletely explained prior accidents (see below) [1], An earlier accident on laboratory scale had also been both reported and thermally investigated [2]. See Acetone... 

Obviously, sleep disorders are a major cause of traffic accidents because of their prevalence but also because of their danger (high-risk ratio of death and injury). If OS AS is a well-covered field, other diseases such as narcolepsy and hypersomnias are not as frequently investigated. This could be explained by the low prevalence and therefore the limited public-health impact of accidents generated by these patients. We strongly believe that research must be conducted in this field to provide better information on the driving aptitude of these patients. 

The frequency of sedation due to acrivastine, cetirizine, fexofenadine, and loratadine has been investigated in four prescription-event monitoring studies in 43 363 patients in general practice in the UK (53). Prescriptions were obtained for each cohort in the immediate postmarketing period. Sedation and drowsiness were the main outcome measures. The odds ratios (adjusted for age and sex) for the incidences of sedation compared with loratadine were 0.63 (95% Cl = 0.36, 1.11) for fexofenadine, 2.79 (1.69, 4.58) for acrivastine, and 3.53 (2.07, 5.42) for cetirizine. There was no increased risk of accident or injury with any of the four drugs. 

W. H. Heinrich from America had attempted amore in-depth study on near miss. He investigated more than 5,000 injuries and found that in 330 similar accidents 300 accidents caused no injuries, 29 cases caused minor injuries along with 1 caused serious injury. That is to say, serious injury, minor injury and no injury accident number ratio is 1 29 300, which is the famous Heinrich law, called the accident triangle, as shown in Figure 3. 

The second view is macroscopic. In case more than one event is evaluated, an aggregation of the single events is possible in order to assess the overall effects. If the sample under investigation happens to contain accident and non-accident events, an accident rate or prevention rate can be calculated as ratio of frequency of accidents (or one minus accidents) with a measure by frequency of accidents without the measure. Summary statistics can also be computed in non-accident events by statistically evaluating the indicators defined on the physical level. In comparison to a baseline without measure the change due to a specific safety measure can be evaluated at the desired level of detail. Within the accident group, rates for specific injury severities as well as a fatality rate can be estimated. 

U.S. Department of Labor, OSHA (2007), in an undated bulletin titled Safety and Health Management Systems eTool—Costs of Accidents says Studies show that the ratio of indirect costs to direct costs varies widely, from a high of 20 1 to a low of 1 1. Geige Safety Group provides OSHA Academy Course 702— Accident Investigation Recommendations (April 2010). They say If the indirect (uninsured) accident cost totals 160,000 and the direct (insured) cost is 40,000, the ratio of indirect to direct costs will be 4 to 1. ... 

Other accident analysis and investigation approaches that make explicit reference to supervision as a potential causal factor include AcciMaps (Svedung and Rasmussen, 2002), which diagrams company management and technical, operational, and management failure levels, and the Incident Cause Analysis Method (ICAM) (BHP Billiton, 2001), which addresses inadequate supervision and poor supervisor or worker ratio error modes. 

Speed is generally associated with injury severity, but it also has a consistent effect on the likelihood of a crash. The MAIDS crash investigation teams concluded that in 8 percent of the crashes the motorcycle s speed contributed to the crash, compared to only 5 percent of the crashes in which the other vehicle s speed contributed to the crash. In Spain, Lardelli-Claret et al. (2005) assessed the accident causes of all the PTW injury collisions that occurred in Spain from 1993 to 2002, that did not involve a pedestrian, and in which only one of the drivers or riders was considered culpable. With a total data base of 128,273 crash-involved mopeds and 62,005 crash-involved motorcycles, they calculated the crash risk of the culpable riders relative to that of the non-culpable riders. After adjusting for various confounding variables, they found that the factors that were most over-involved in culpable crashes were inappropriate speed (with an odds ratio of 13 for motorcycles and 10 for mopeds), and excessive speed (with an odds ratio of 7 for motorcycles and 6 for mopeds). The effects of speed in general are discussed in much more details in Chapter 8). 

The activity ratio Pu/ Pu varies depending on source term such as weapon plutonium, fallout from nuclear tests, the Chernobyl accident and releases from nuclear fuel reprocessing plants. The objective of this project was to investigate if there was any close fallout over Madagascar even if it was claimed that all Pu was evaporated in the upper atmosphere. 

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