Explain the levels of legal and institutional independence of the public power and the main criteria and methodologies for analyzing the following ...

Explain the levels of legal and institutional independence of the public power and the main criteria and methodologies for analyzing the following public organizations dedicated to investigating railway accidents: United Kingdom: Rail Accident Investigation Branch (RAIB) 25 United States: National Transportation Safety Board (NTSB) 26 Spain: Commission for the Investigation of Railway Accidents (CIAF) 27 France: Bureau of Investigations into Land Transport Accidents (Bureau d'Enquêtes sur les Accidents de Transport Terrestre - BEA-TT) 28 Germany: Federal Railway Accident Investigation Board (Eisenbahn-Unfalluntersuchungsstelle des Bundes - EUB) 29 Australia: Australian Transport Safety Bureau (ATSB) 30 Canada: Transportation Safety Board of Canada (TSB) 31 The main common notes of all these organizations can be summarized (beyond nuances and national particularities) as:
Levels of legal and institutional independence of the public power
Main criteria and methodologies for analyzing public organizations dedicated to investigating railway accidents
All these agencies are endowed with full functional independence from the authority responsible for the transport system, the authority responsible for safety, and any other railway regulator or operator.
The purpose of the investigations is not to establish guilt or responsibility, the Investigation of Accidents / incidents are procedures for determining facts and circumstances, therefore, it is not considered appropriate for these reports to be used to assign fault(s) or guilt(s), or to determine responsibility(ies), since neither the investigation nor the process of elaboration and presentation of reports is carried out for this purpose.
The framework for analysis is that of a systemic approach, that is, one that considers all the variables involved in an accident, from strictly technological ones (material and equipment failures), to those related to human nature (human failures) passing through (and considering them especially) those that refer to the operator's own organizational structure and the current regulatory system, aimed at serving as a basis for proposing measures and actions aimed at avoiding their repetition.
The valorization, almost above investigative details, of the issuance of Safety Recommendations aimed precisely at forming a shared knowledge that allows avoiding the repetition of accidents.
In all the cases analyzed (and in others similar) the need for the analysis of the so-called "near miss" or "quasi-accidents" cases is also emphasized; episodes in which, except for a tragic or catastrophic ending, most of the factors involved in a serious accident are present. The problem posed by this type of incident is that railway service operating companies (and also airlines) are reluctant to show this side of their daily operation.