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". 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 led to the incident.

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. However, most organizations follow some form of these steps, in this order:

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.

Accident analysis breaks down the mechanisms of accidents and provides essential knowledge for the identification of hazards and justification for safety measures. To produce useful knowledge and avoid overlooking potential accident events, accident analysis should strive to identify as many hazardous events as possible. Among the methods that can contribute to greater extraction of information, we can identify the Accident Anatomy (AA) method, AcciMap, Systems-Theoretic Accident Model and Processes (STAMP), and Functional Resonance Analysis Method (FRAM). However, these methods have their limitations. The AA method and AcciMap appear to better meet the completeness requirements in the analysis. However, the AA method readily serves not only as a method for post-accident analysis (the analysis of multiple accident reports through post-accident analyses to assess as many recorded events as available) but also allows us to conduct predictive analysis. The latter analysis is carried out by identifying the deviations from operational and emergency procedures and the associated events that may lead ultimately to accidents. The joint use of post-accident and predictive analyses in the AA method is likely to result in increased knowledge delivery.

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

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).

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.

Recent advancements in technology have significantly enhanced the process of trucking collision analysis, allowing investigators to understand, prevent, and resolve accidents with greater precision and efficiency. These innovations provide detailed insights into the causes of accidents, help determine liability, and contribute to improving overall road safety.