Accident scene

The area of a traffic accident before the vehicles and people involved have left [ISO 12353–1:2002].

Accident site

The geographic location of the accident scene (note: the accident site may be given as exact coordinates or in a less detailed way) [ISO 12353–1:2002].

Accident causation

To analyse the accident scenarios and background factors (human, vehicle, and environment) to discover the accident mechanisms linking the contributing factors and consequences (human error, personal injury, etc.). Accident causation aims to identify the weak points in the road transport system in such a way to be able to appropriately address them.

Case analysis

The analysis is conducted by use of available data and computation or coding of new data after completion of data collection by the case group.


A case is a separate accident (could also be a multiple accident) that has been chosen for investigation and analysis. A case is opened the moment an accident is being chosen for investigation. Each crash investigation is treated as a case.

Crash Phases (as defined in INTACT and ISO 12353–1:2002)

Pre-crash phase
The pre-crash phase starts from the precipitating event when the trip begins and ends at contact with a collision object or a roll-over.
-Relevant background factors beyond those in the pre-crash phase are included in the analysis. They can lie back in the past, e.g. months or weeks before the trip.
Crash phase
The crash phase starts with contact with a collision object or a roll-over and ends at final rest position.
Post-crash phase
The post-crash phase starts when the contact finishes and ends at final rest position.
Follow up investigation
Follow up starts at final rest position and covers rescue work, hospital treatment, crash reconstruction and long term injury follow-up.
Note: the phases can differ between road users in the same accident.
Crash investigation

Acquisition of factual information regarding an accident (note: can include on-scene elements, elements recorded retrospectively, or both of these) [ISO 12353–1:2002].

Crash notification

A message/phone call from the emergency service/traffic police/authorities is sent to the on-scene team when an accident occurred (according to the sampling criteria).

Data analysis

Analysis of available data and computation or coding of new data after completion of data collection

Data collection

Objective data collected on-scene, retrospectively or data retrieved from other sources. Data collection also includes subjective information, such as interviews.


A person with expert knowledge in one or more areas of crash investigation

On-scene (crash) investigation

Crash investigation conducted at the accident scene with the purpose of collecting on-scene information before physical evidence (e.g. the vehicles involved) has been removed [ISO 12353–1:2002].

On-scene team

The on-scene team consists of investigators included in the case group ready to respond to a crash notification and perform on-scene investigations.

Pre-crash phase sequential analysis (as defined by IFSTTAR)

Segmentation of the factual pre-crash phase into various sequences: (a) the situation prior to driving (should sufficient information be available), (b) the driving situation, which describes the conditions and driving activity on the route and the section of route leading to the accident site, (c) the accident situation or rupture situation: instantaneous, distinguished by an event (e.g. a manoeuvre at an intersection) or kinematics conditions (e.g. a high speed on approaching a difficult bend) indicating a shifting over to a critical situation (the emergency situation described below), (d) the emergency situation where only extreme manoeuvres could still, in some cases, prevent the crash.

Retrospective (crash) investigation

A complete crash investigation conducted retrospectively, i.e. no on-scene investigation is conducted.

Retrospective inspection

When an on-scene crash investigation has been conducted, retrospective inspections of vehicles or infrastructure are conducted.

Retrospective team

The retrospective team consists of investigators included in the case group performing retrospective investigations.

Road vehicle crash

Unintended event, which involves at least one vehicle in motion, and leads to personal injury or property damage, or both [ISO 12353–1:2002].

Sampling criteria

Principle of evaluation of scope and coverage of a crash investigation referring to different aspects [ISO 12353–1:2002]. NOTE: Aspect of a crash investigation can include: road user, vehicle, injury or fatality, traffic environment and/or property damage.


An analytical step in the Investigation process. All tasks are assigned to an Investigator role.

Team organizer

Person in charge of the investigators, monitors progress and assigns case leaders.


A variable is a parameter collected during the crash investigation or coded and computed afterwards. In case of an ordinal variable several values can be chosen, e.g. “car body style” can have the possible values of “Sedan”, “Hatchback/wagon”, “Sports”, “Convertible”, “Derivative”, “Off-road/SUV”, “MPV/Minibus”, “Pick-up” and “Van”. For numeric variables actual values can be applied, e.g. the pre-crash velocity of a vehicle. A variable can also have the character of a text comment field.