Interview Guidelines

Navigation Links

Purpose / Aim

The act of interviewing road users regarding a road traffic accident is an involved task due to the emotional signifigance, legal context and the practical conditions. There is therefore a requirement to adapt the interview method accordingly. The purpose of the Interview Guidelines section is to describe the difficulties likely to be encountered in the application of the semi-directive interview method as well as some of the techniques which are advisable to implement to mitigate these difficulties.


In-depth accident studies rely upon a detailed approach designed at gaining as much information about the event as possible (clinical type approach). The collection of data is inevitably interdisciplinary and thus a number of investigators are active concurrently. These investigators are specialist in (amoung others) the dynamics of vehicles, kinematics, mechanics, biomechanics, infrastructure and psychology.

The consideration of the "human factor" (road users) in its interaction with the other components of the Vehicle-Human-Environment system implies a psychological dimension. The ideal is to rely on the expertise of specialists in the study of human operator behaviour when engaged in the driving task (ergonomics, cognitive psychology) for the collection of human data and the analysis of their influence in the accident mechanisms. In any case, the interviewer having an understanding of the human processes at play in driving and in accidents is highly desirable.

The following sections summarise the difficulties likely to be met in the course of the interview in the particular context of the accident, and provides some techniques which can be implemented to mitigate these difficulties: which attitude to adopt with the interviewees, how to establish a good interview relationship, how to engage the person in the interview, which questioning techniques to use, which adaptive procedures are effective, how to manage interventions from other people (in the case where others are present e.g. at the accident scene).

The Interview Guideline Methodology also attempts to detail how to utilise information gained through exchanges with the investigator and the importance of relating with the people involved (i.e. rescue services, police, etc.).

1. Timing

In regards to the determining when to conduct the interview, the ideal situation would be to conduct the interview as soon as possible, in consideration of the availability of the people involved. This is done so that the interviewee delivers the most spontaneous information, before mental reconstruction or mediation takes place as a result of discussion with others.

An efficient way of proceeding relies upon a data collection procedure divided into two stages:

1. An initial interview: a relatively brief (considering the circumstances) on-scene interview at the accident scene (or in the emergency rooms of the hospital).

2. A follow-up interview: a complementary data collection interview within 48 hours of the accident. The investigators should direct their questions based on their initial understanding of the accident, resulting from the initial interview and an examination of the first data collected by the interdisciplinary team.

The collection of immediate recollections improves the chances of receiving genuine and more accurate statements from interviewees, without interference resulting from the interviewee talking with others about the accident or mental reconstruction self-reflection regarding the events. In the absence of these conditions, it is necessary to be aware of the biases which can affect the testimony.

2. Preparation

The interviewer has to approach the interviewees without any preconceptions to avoid the risk of biasing the interview by questioning directed subjectively. But not having preconceptions does not mean being ignorant of any available information. It is necessary to prepare for the interview by becoming familiar with the material circumstances of the accident.

It is useful to know beforehand: the number of vehicles involved, the overall configuration of the crash, available evidence, etc. In this respect, to have observed beforehand the site of the accident constitutes a main requirement for an effective interview and an understanding of the facts described by the road users. This preparation can develop from dialogue with other investigators involved in the case analysis. This preliminary information does not have to result in conclusions, but to assist investigators in determining appropriate questions to ask.

More generally speaking, investigators must have an understanding the different topics they are required to cover during the interview. The use of an interview guide is useful during the interview to verify the points which have not been developed yet. But this guide should not be followed too rigidly: a good interview occurs when the different questions come about naturally, as would happen in normal conversation.

Indeed, the reactions of the interviewee in these particular conditions can be very diverse and the interviewers should account for these diffrences and adapt accordingly, in respect for those involved, the ethical rules, and in the objective to collect the best information necessary for the understanding of the accident. The technique of the "semi-directive" interview must, according to the particular situation, be revised either:

  • "Downward": to reduce the rigidity of the interview and allow the interviewee to express themselves freely on a subject which affects them, even if it does not interest directly the analysis of the accident (e.g. when the person is manifesting a very strong emotion)


  • "Upward": encouraging the interviwee to clarify any discrepancies or suspected misappropriated statements to ensure their claims are reliable and accurate, even if it means pushing the person in a more directive way (e.g. when this person is obviously insincere or resistant).

3. Interview Commencement

To achieve an efficient interview, the investigator needs not only the agreement of the interviewee, but even more so the investigator needs to instill a sense of support in the interviewee for the project and its aim to investigate all the facts of the accident. The interviewer should emphasize the importance of the results of the overall project in improving road safety. The quality of the introduction influences the quality of the following of the interview, so it is advisable to take the necessary time to do the following:

  • Introduce oneself by name and role, do not hesitate to give your name
  • Briefly introduce the DaCoTA project and it's purpose
  • Present the frame and the purpose of the work. Keep explanations concise and factually based (i.e. "We analyse vehicular accidents to understand how and why they happen, to hopefully determine how to reduce the number and severity of future accidents. You're witness account of the accident event is vital to our research").
  • Reassure the interviewee by stating the ethical guarantees of discretion and non-disclosure of the contents of the interview (independence with regard to investigations of police or justice, anonymity in the use of the results).
  • If necessary, involve the interviewee in this work, by assigning them the role of an irreplaceable witness (i.e. "How did this accident occur? I need you to explain it to me what happened to understand the events that led to the accident. Your witness account is one of the most vital components to our understanding of the accident.". Remind him/her that this study can allow the prevention of other accidents.
  • Outline the protocol for the interview. "I would like to begin by listening to your account of the accident in as much detail as possible.". Then proceed with the interview: "Is that OK? Do you understand? We will start now... ".

4. Questioning

The investigation should cover the follow topics:

  1. The preliminary driving situation, momentarily prior to the accident event (speed of approach, intentions, expectations).
  2. The nature and the conditions of the problem encountered (manoeuvres made by themselves and of others).
  3. The emergency situation (protective manoeuvres).
  4. The collision event itself.

For each of these phases, the interviewer must gather information on the nature of the perceived elements, the interpretations, the decisions and the operations made. In order of importance, the first key question is "How?", the second is "Why?" (i.e. "What did you do?", and "Why that way?").

As a general rule, a novice investigator may be satisfied with general answers, and believes to have understood everything at the very moment when numerous details or answers remain ambiguous or unanswered (i.e. a person who says " I did not see him arriving" can really mean, "I did not see that he arrived so fast").

We recommend three distinct phases in the interview: a first phase (Open Phase) of listening centred on the progress of the accident, a second phase (Deepening Phase) of gaining a deeper understanding and questioning on this progress and a third phase (Filling-in Phase) centred on the contents of the information check list.

1. Open Phase

It is better to begin with the progress of the accident as it may be what the interviewee expects. In the first stage, the principle is to let the interviewee speak as freely possible, for as long as they chosse to speak (as long as they remain on subject).

The Open Phase is initialized by an open question, such as "Can you tell me how that took place?". The purpose of the Open Phase is to collect an overall view of the accident, while retaining as much detail as possible.

It is the interviewee who knows what took place and it the task of the investigator to listen to them. If the interview begins with closed questions, the interviewer risks disengaging the interviewee, putting him in a situation of unpleasant interrogation, into a passive position of waiting for the following question, thereby running the risk of discouraging the information source.

Also, the investigator will avoid premature interruptions as the risk is too great of preventing the interviewee from delivering relevant information that may not have been revealed otherwise. In this stage, it is recommended to allow freedom of expression on behalf of the interviewee. This allows the interviewee to become comfortable with the interviewer and to feel confident in giving their response.

Deepening Phase

The second stage consists of an exploration of the information gathered during the Open Phase, hopefully leading to a deeper understanding of the accident. The Deepening Phase should concentrate on specific details, to investigate the "blanks", the ambiguities and the contradictions. This stage is more directive, the questioning is therefore more methodical. The investigator uses what he knows already to gain further knowledge. Once again, a good knowledge of the accident facts will help at this stage.

Filling-in Phase

The final stage, the Filling-in Phase constitutes a change in the content of the interview which may reveal new information. It is good to make a transition. It is suggested that this transition is introduced, i.e., "I would now like to ask questions which concern you more personally, as we try to understand if there are other background factors that alter the risk of having an accident. For example, I would like you to tell me about your experience of driving, how long have you driven, on which roads, your annual mileage...”, etc. With such an introduction, the interviewee finds it normal to answer questions of this nature.

It is recommended that the investigator continues to conduct the interview in the manor of conversation which it had until then. The use of a check list as a questionnaire at this stage may detract from the interview by asking questions mechanically, one after the other. As mentioned earlier, the check list is only a list of themes to be investigated. It is best for the investigator to have them in mind and possibly consult it as a reminder, to verify that nothing was forgotten.

Throughout the interview, it is important to be reminded that the information collected will eventually be coded into the DaCoTA database: the investigator must have studied carefully this coding, to verify that the answers will allow it to be easily entered into the database.

5. Additional Considerations


It is sensible for the investigator to adopt a level of language similar to that of the interviewee for a better understanding and to adapt his speech to the capacity and the personality observed. This process has the advantage of motivating the verbal productions of the interviewee by relating to them.

Giving to the interview the feeling of a conversation allows it to pass from one theme to another naturally by the association of ideas. Although the order of the themes may not reflect that of a formalised check list, being well linked in the conversation may foster a more natural environment to encapsulate the details from an interviewee as long as all the themes are covered.


The investigator may be regularly confronted with uncomfortable feelings depending on the nature of the accident. Meeting with interviewees who are in distress after recently being involved in a traffic accident, it is sometimes difficult to assume a professional investigation approach. Therefore, investigators must conduct themselves professionally, in such a way that they can overcome any anxiety or nervousness. It is essential to remember that the primary motive of the investigation and the investigator is to collect relevant data to better understand the accident.

Testimony Reliability

The verbal testimony of the road user involved in the accident is essential for the reconstruction of events and analysis of the accident. It is therefore advisable to be aware of the various biases which can be found in the statements of involved road users. The analysis of these statements thus requires a certain caution, as inaccuracies and distortions (deliberate or not) can occur at various levels. Some sources and examples of bias to be considered are detailed as follows:

  • The Forgery: the road user deliberately gives a version of the facts which releases him from the responsibility. It is here that the ability of the investigator to acquire the trust of the interviewee about the confidentiality of the data which is collected is important.
  • The Justification: the road user tries to prove, to others and themselves, that their behaviour obeyed a certain logic, coherent with the capacities of a "good driver", protecting implicitly their actions. They can sometimes persuade themselves that what was had envisaged beforehand as a hypothesis is fact.
  • The Rational Reconstruction: the user reconstructs the chain of his actions from the elements which he memorized, but he involuntarily fills in the gaps by resorting to his mental representation of his task and his usual ways of functioning.
  • The Bias of Analysis: the gap between the declarations and the facts can also be revealing mechanisms of errors with which were confronted by the persons. Such inaccuracies are of interest from the point of view of the understanding the difficulties really met by the interviewee in situations, in regards to their perception and interpretation of the process.

Certain inaccuracies are thus voluntary and many others unconscious. The experience of the investigators is paramount in the ability to disentangle these various biases in the speech and to allow them to grant more or less credit to the narrative of the road users.


Please refer to the main Equipment List for the Inerview Guidelines equipment list.


Please refer to the Arrangement section of the Methodology Outline Behavioural Data section.