Glossary of Data Variables for Fatal and accident causation ... - ERSO

Manual For SafetyNet accident causation system (SNACS)
6.4.2 Interview data
Also, regarding the second type of data, that is interview material, a few points
can be made. First off, there is no such thing as an objective description of
the accident event. Every story told is a story from someone's particular point
of view, and even though this is nothing new, we all need to keep it in mind
when analysing interview data.
Secondly, event though most drivers have quite extensive driving experience,
very few have experience of accidents. This means that they never have
practiced observing and reporting on accidents, and therefore the account they
give will be a reconstruction based on what seems plausible to them. When
doing this mental reconstruction of the event, people will invoke what they
“generally know” about how accidents happen.
Such general knowledge is sometimes called scripts, or action sequence
patterns. If there is a gap in a description of an event, people will fill in that gap
with what they believe is most likely. An example of such a script would be that
“if you are about to run into something and detect this, the logical thing to do is
to brake”. Braking is part of the collision avoidance script. Hence, an
interviewed driver will probably claim to have braked if he had time to realise
that he was in danger. This means that whether or not he actually did brake has
to be verified in other ways.
That verification is also necessary because as stated among the principles for
human behaviour above, a large part of human behaviour is automated and
unconscious. Such behaviours are by nature very difficult to recall consciously,
since they were not carried out as part of a conscious control process. In
driving, this is particularly true for low level control tasks, such as accelerating,
braking, steering and shifting gears. In fact, the demand in driver’s education is
generally that the driver should not receive his licence until these behaviours
are automated, because otherwise the driver cannot keep his attention on the
surrounding traffic.
Asking the driver whether s/he did brake or accelerate at a certain point in time
is therefore a very difficult question to ask. This behaviour instead generally has
to be inferred from the driver’s description of his actions prior to the event. For
example, from a narrative like “I was standing still, and then the light turned
green, so I started driving…” we can infer that the driver released the brake
pedal, put his left foot on the clutch (if driving a manual shift) pressed down the
accelerator with his right foot while releasing the clutch, and so forth.
Another thing about interviewing people is that the choice of words is important.
People will be influenced by the words chosen in the description of an event. A
classical example is Loftus and Palmer’s study from 1974. Test persons
watched a movie where two cars collide. Then they got the question ”How fast
were the cars going when they (their average answers in brackets):
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