Accident analysis

Last updated
Police study the site where a car crashed 325 E58 after car crash 2017-10 jeh.jpg
Police study the site where a car crashed

Accident analysis is a process carried out in order to determine the cause or causes of an accident (that can result in single or multiple outcomes) so as to prevent further accidents of a similar kind. It is part of accident investigation or incident investigation . These analyses may be performed by a range of experts, including forensic scientists, forensic engineers or health and safety advisers. Accident investigators, particularly those in the aircraft industry, are colloquially known as "tin-kickers". [1] Health and safety and patient safety professionals prefer using the term "incident" in place of the term "accident". Its retrospective nature means that accident analysis is primarily an exercise of directed explanation; conducted using the theories or methods the analyst has to hand, which directs the way in which the events, aspects, or features of accident phenomena are highlighted and explained. These analyses are also invaluable in determining ways to prevent future incidents from occurring. They provide good insight by determining root causes, into what failures occurred that lead to the incident. [2]

Contents

Sequence

Accident analysis is generally performed in four key steps. OSHA combines the last two steps into a singular final step of preparing and issuing a report. [3] However, most organizations follow some form of these steps, in this order:

  1. Fact gathering: After an accident, a forensic process is started to gather all possibly relevant facts that may contribute to understanding the accident. This can be physical evidence, digital evidence, and/or first-hand accounts from witnesses. In occupational settings, this could also be records of machinery, personnel present, and operating procedures. [3]
  2. Fact Analysis: After the forensic process has been completed or at least delivered some results, the facts are put together to give a "big picture." The history of the accident is reconstructed and checked for consistency and plausibility. This is also where the use of analysis methods can come into play.
    Hierarchy of Controls from NIOSH NIOSH's "Hierarchy of Controls infographic" as SVG.svg
    Hierarchy of Controls from NIOSH
  3. Conclusion Drawing: If the accident history is sufficiently informative, conclusions can be drawn. These conclusions can be firm findings that were direct causing factors or they can be a list of possible contributing factors.
  4. Counter-measures: In some cases, the development of counter-measures or recommendations are made to prevent further accidents of the same kind. The analysis step can also aid in pointing out other possible risk factors that could be mitigated during this step. These counter measures can be things like the implementation of controls following the hierarchy of controls.

Methods

There exist numerous forms of Accident Analysis methods. These can generally be divided into four main categories which break up how and who completes the analysis.

  1. Causal Analysis (Root cause analysis) uses the principle of causality to determine the course of events. Though people casually speak of a "chain of events", results from Causal Analysis usually have the form of directed a-cyclic graphs  the nodes being events and the edges the cause-effect relations. Methods of Causal Analysis differ in their respective notion of causation. [4]
  2. Systematic Analysis relies on using a standardized system or model for developing conclusions. This tends to be a rigorous effort that is performed by an expert. This method leaves little room for doubt and can be beneficial by ensuring expert bias does not come into play. [4]
  3. Expert Analysis relies on the knowledge and experience of field experts. This form of analysis usually lacks a rigorous (formal/semiformal) methodological approach. This usually affects falsifiability and objectivity of analyses. This is of importance when conclusions are heavily disputed among experts. [5]
  4. Organizational Analysis relies on systemic theories of organization. Most theories imply that if a system's behaviour stayed within the bounds of the ideal organization then no accidents can occur. Organizational Analysis can be falsified and results from analyses can be checked for objectivity. Choosing an organizational theory for accident analysis comes from the assumption that the system to be analysed conforms to that theory.

Models

Many models or systems have been developed to characterise and analyse accidents. [6]

Template for an Ishikawa diagram Third Step of Ishikawa diagram.png
Template for an Ishikawa diagram

Some of common models are similar to Hazard Analysis models. When used for accident analysis they are worked in reverse. Instead of trying to identify possibly problems and ways to mitigate those problems, the models are used to find the cause of an incident that has already occurred. Some common types of these models include the Five Why's model, Ishikawa (fishbone) diagram, the Fault Tree Analysis (FTA), or the Failure Mode and Effect Analysis (FMEA). [4]

  1. Five Why's Model: Also known as "Why-Because" model, this model uses the idea of breaking an incident up into the fine details. Asking why something occurred, and what occurred that made that happen. It is used to determine exact causes and can extend much beyond a simple "five" whys.
  2. Ishikawa Diagram: Takes into account environmental, human, methodical, and equipment causes that can lead to a problem. Using this model, an accident analyst could work backwards from the problem to find and mitigate potential causes.
  3. Fault Tree Analysis: Uses a tree type "yes/no" cause and effect analysis to determine potential causes of failures. In accident analysis it could be used to determine leading factors, post-incident. This model works like a flow chart to help show all processes and systems that may have effected the outcome of the incident.
  4. Failure Mode and Effect Analysis: This model uses a quantitative value to represent qualitative metrics like probability and severity. These values rank 1–5 with 1 being least probable or least severe and 5 being most probable or severe. The probability and severity values are then placed into a risk matrix to determine the overall risk. This can be beneficial in incident analysis by helping to determine other risk factors that could occur once an incident has happened. [4]

Using photographs to extract evidence

Once all available data has been collected by accident scene investigators and law enforcement officers, camera matching, photogrammetry or rectification can be used to determine the exact location of physical evidence shown in the accident scene photos.

  1. Camera matching: Camera matching uses accident scene photos that show various points of evidence. The technique uses CAD software to create a 3-dimensional model of the accident site and roadway surface. All survey data and photos are then imported into a three dimensional software package like 3D Studio Max. A virtual camera can be then be positioned relative to the 3D roadway surface. Physical evidence is then mapped from the photos onto the 3D roadway to create a three dimensional accident scene drawing.
  2. Photogrammetry: Photogrammetry is used to determine the three-dimensional geometry of an object on the accident scene from the original two dimensional photos. The photographs can be used to extract evidence that may be lost after the accident is cleared. Photographs from several viewpoints are imported into software like PhotoModeler. The forensic engineer can then choose points common to each photo. The software will calculate the location of each point in a three dimensional coordinate system. [7]
  3. Rectification: Photographic rectification is also used to analyze evidence that may not have been measured at the accident scene. Two dimensional rectification transforms a single photograph into a top-down view. Software like PC-Rect can be used to rectify a digital photograph. [8]

Footnotes

Related Research Articles

Voice analysis is the study of speech sounds for purposes other than linguistic content, such as in speech recognition. Such studies include mostly medical analysis of the voice (phoniatrics), but also speaker identification. More controversially, some believe that the truthfulness or emotional state of speakers can be determined using voice stress analysis or layered voice analysis.

<span class="mw-page-title-main">Forensic engineering</span> Investigation of failures associated with legal intervention

Forensic engineering has been defined as "the investigation of failures—ranging from serviceability to catastrophic—which may lead to legal activity, including both civil and criminal". It includes the investigation of materials, products, structures or components that fail or do not operate or function as intended, causing personal injury, damage to property or economic loss. The consequences of failure may give rise to action under either criminal or civil law including but not limited to health and safety legislation, the laws of contract and/or product liability and the laws of tort. The field also deals with retracing processes and procedures leading to accidents in operation of vehicles or machinery. Generally, the purpose of a forensic engineering investigation is to locate cause or causes of failure with a view to improve performance or life of a component, or to assist a court in determining the facts of an accident. It can also involve investigation of intellectual property claims, especially patents. In the US, forensic engineers require a professional engineering license from each state.

<span class="mw-page-title-main">Fault tree analysis</span> Failure analysis system used in safety engineering and reliability engineering

Fault tree analysis (FTA) is a type of failure analysis in which an undesired state of a system is examined. This analysis method is mainly used in safety engineering and reliability engineering to understand how systems can fail, to identify the best ways to reduce risk and to determine event rates of a safety accident or a particular system level (functional) failure. FTA is used in the aerospace, nuclear power, chemical and process, pharmaceutical, petrochemical and other high-hazard industries; but is also used in fields as diverse as risk factor identification relating to social service system failure. FTA is also used in software engineering for debugging purposes and is closely related to cause-elimination technique used to detect bugs.

In science and engineering, root cause analysis (RCA) is a method of problem solving used for identifying the root causes of faults or problems. It is widely used in IT operations, manufacturing, telecommunications, industrial process control, accident analysis, medicine, healthcare industry, etc. Root cause analysis is a form of inductive and deductive inference.

Stress–strain analysis is an engineering discipline that uses many methods to determine the stresses and strains in materials and structures subjected to forces. In continuum mechanics, stress is a physical quantity that expresses the internal forces that neighboring particles of a continuous material exert on each other, while strain is the measure of the deformation of the material.

A hazard analysis is used as the first step in a process used to assess risk. The result of a hazard analysis is the identification of different types of hazards. A hazard is a potential condition and exists or not. It may, in single existence or in combination with other hazards and conditions, become an actual Functional Failure or Accident (Mishap). The way this exactly happens in one particular sequence is called a scenario. This scenario has a probability of occurrence. Often a system has many potential failure scenarios. It also is assigned a classification, based on the worst case severity of the end condition. Risk is the combination of probability and severity. Preliminary risk levels can be provided in the hazard analysis. The validation, more precise prediction (verification) and acceptance of risk is determined in the risk assessment (analysis). The main goal of both is to provide the best selection of means of controlling or eliminating the risk. The term is used in several engineering specialties, including avionics, food safety, occupational safety and health, process safety, reliability engineering.

<span class="mw-page-title-main">Traffic collision reconstruction</span> Process for investigating vehicle collisions

Traffic collision reconstruction is the process of investigating, analyzing, and drawing conclusions about the causes and events during a vehicle collision. Reconstructionists conduct collision analysis and reconstruction to identify the cause of a collision and contributing factors including the role of the driver(s), vehicle(s), roadway and general environment. Physics and engineering principles are the basis for these analyses and may involve the use of software for calculations and simulations. Collision reconstruction is sometimes used as the basis of expert witness testimony at trials. Collision reconstructions are performed in cases involving fatalities or personal injury. Results from collision reconstructions are also sometimes used for making roads and highways safer, as well as improving safety aspects of motor vehicle designs. Reconstructions are typically conducted by forensic engineers, specialized units in law enforcement agencies, or private consultants.

<span class="mw-page-title-main">Forensic photography</span> Art of producing an accurate reproduction of a crime scene

Forensic photography may refer to the visual documentation of different aspects that can be found at a crime scene. It may include the documentation of the crime scene, or physical evidence that is either found at a crime scene or already processed in a laboratory. Forensic photography differs from other variations of photography because crime scene photographers usually have a very specific purpose for capturing each image. As a result, the quality of forensic documentation may determine the result of an investigation, in that with the absence of good documentation, investigators may find it impossible to conclude what did or did not happen.

The following outline is provided as an overview of and topical guide to forensic science:

<span class="mw-page-title-main">Swiss cheese model</span> Model used in risk analysis

The Swiss cheese model of accident causation is a model used in risk analysis and risk management, including aviation safety, engineering, healthcare, emergency service organizations, and as the principle behind layered security, as used in computer security and defense in depth. It likens human systems to multiple slices of Swiss cheese, which has randomly placed and sized holes in each slice, stacked side by side, in which the risk of a threat becoming a reality is mitigated by the differing layers and types of defenses which are "layered" behind each other. Therefore, in theory, lapses and weaknesses in one defense do not allow a risk to materialize, since other defenses also exist, to prevent a single point of failure. The model was originally formally propounded by James T. Reason of the University of Manchester, and has since gained widespread acceptance. It is sometimes called the "cumulative act effect".

The system safety concept calls for a risk management strategy based on identification, analysis of hazards and application of remedial controls using a systems-based approach. This is different from traditional safety strategies which rely on control of conditions and causes of an accident based either on the epidemiological analysis or as a result of investigation of individual past accidents. The concept of system safety is useful in demonstrating adequacy of technologies when difficulties are faced with probabilistic risk analysis. The underlying principle is one of synergy: a whole is more than sum of its parts. Systems-based approach to safety requires the application of scientific, technical and managerial skills to hazard identification, hazard analysis, and elimination, control, or management of hazards throughout the life-cycle of a system, program, project or an activity or a product. "Hazop" is one of several techniques available for identification of hazards.

Process safety is an interdisciplinary engineering domain focusing on the study, prevention, and management of large-scale fires, explosions and chemical accidents in process plants or other facilities dealing with hazardous materials, such as refineries and oil and gas production installations. Thus, process safety is generally concerned with the prevention of, control of, mitigation of and recovery from unintentional hazardous materials releases that can have a serious effect to people, plant and/or the environment.

<span class="mw-page-title-main">Forensic materials engineering</span>

Forensic materials engineering, a branch of forensic engineering, focuses on the material evidence from crime or accident scenes, seeking defects in those materials which might explain why an accident occurred, or the source of a specific material to identify a criminal. Many analytical methods used for material identification may be used in investigations, the exact set being determined by the nature of the material in question, be it metal, glass, ceramic, polymer or composite. An important aspect is the analysis of trace evidence such as skid marks on exposed surfaces, where contact between dissimilar materials leaves material traces of one left on the other. Provided the traces can be analysed successfully, then an accident or crime can often be reconstructed. Another aim will be to determine the cause of a broken component using the technique of fractography.

A Technique for Human Event Analysis (ATHEANA) is a technique used in the field of human reliability assessment (HRA). The purpose of ATHEANA is to evaluate the probability of human error while performing a specific task. From such analyses, preventative measures can then be taken to reduce human errors within a system and therefore lead to improvements in the overall level of safety.

Accident classification is a standardized method in accident analysis by which the causes of an accident, including the root causes, are grouped into categories. Accident classification is mainly used in aviation but can be expanded into other areas, such as railroad or health care. While accident reports are very detailed, the goal of accident classification is to look at a broader picture. By analysing a multitude of accidents and applying the same standardized classification scheme, patterns in how accidents develop can be detected and correlations can be built. The advantage of a standardized accident classification is that statistical methods can be used to gain more insight into accident causation.

<span class="mw-page-title-main">Digital forensic process</span>

The digital forensic process is a recognized scientific and forensic process used in digital forensics investigations. Forensics researcher Eoghan Casey defines it as a number of steps from the original incident alert through to reporting of findings. The process is predominantly used in computer and mobile forensic investigations and consists of three steps: acquisition, analysis and reporting.

Human factors are the physical or cognitive properties of individuals, or social behavior which is specific to humans, and influence functioning of technological systems as well as human-environment equilibria. The safety of underwater diving operations can be improved by reducing the frequency of human error and the consequences when it does occur. Human error can be defined as an individual's deviation from acceptable or desirable practice which culminates in undesirable or unexpected results.

Dive safety is primarily a function of four factors: the environment, equipment, individual diver performance and dive team performance. The water is a harsh and alien environment which can impose severe physical and psychological stress on a diver. The remaining factors must be controlled and coordinated so the diver can overcome the stresses imposed by the underwater environment and work safely. Diving equipment is crucial because it provides life support to the diver, but the majority of dive accidents are caused by individual diver panic and an associated degradation of the individual diver's performance. - M.A. Blumenberg, 1996

The AcciMap approach is a systems-based technique for accident analysis, specifically for analysing the causes of accidents and incidents that occur in complex sociotechnical systems.

Tripod Beta is an incident and accident analysis methodology made available by the Stichting Tripod Foundation via the Energy Institute. The methodology is designed to help an accident investigator analyse the causes of an incident or accident in conjunction with conducting the investigation. This helps direct the investigation as the investigator will be able to see where more information is needed about what happened, or how or why the incident occurred.

Investigation of diving accidents includes investigations into the causes of reportable incidents in professional diving and recreational diving accidents, usually when there is a fatality or litigation for gross negligence.

References

  1. Faith, Nicholas (1997). Black Box: Why Air Safety Is No Accident. Zenith Imprint. p. 6. ISBN   0-7603-0400-9.
  2. "A BREAKDOWN OF THE INCIDENT INVESTIGATION PROCESS". www.safetyresources.com. Retrieved 2023-11-26.
  3. 1 2 U.S. Occupational Safety and Health Administration (February 19, 2014). "A Step-By-Step Guide: Incident Investigations" (PDF). Retrieved November 27, 2023.
  4. 1 2 3 4 "Incident analysis methods". www.ehsdb.com. Retrieved 2023-11-28.
  5. "What is Expert Analysis? | Adding Context to Metrics | Help & Documentation". help.metricinsights.com. Retrieved 2023-11-28.
  6. Taylor, G.A.; Easter, K.M.; Hegney, R.P. (2004). Enhancing Occupational Safety and Health. Elsevier. pp. 241–245. ISBN   0750661976.
  7. "Forensic Analysis - Photography | Collision Research". www.collisionresearch.com. Retrieved 2023-11-28.
  8. Extracting Physical Evidence from Digital Photographs for use in Forensic Accident Reconstruction, David Danaher, P.E., Jeff Ball, Ph.D., P.E., and Mark Kittel, P.E 2012-06-15.