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

Manual For SafetyNet accident causation system (SNACS)
contacted each other
hit each other
bumped each other
smashed each other
(31 mph ~ 50 km/h)
(34 mph ~ 55 km/h)
(38 mph ~ 61 km/h)
(41 mph ~ 66 km/h)
One week later they came back and got the question ”was there any broken
glass” (There was no broken glass). 32% of the “smashed” respondents said
yes, while only 14% of the “hit” respondents answered yes.
Another example that relates even closer to our work is in Loftus from 1975,
where a number of persons were asked to watch a car crash on video, and then
had to answer one of the two questions:
• ”How fast was the white car going when it passed the barn on the
country road”
• ”How fast was the white car going on the country road”
The fact is that there was no barn in the video. One week later, the persons
were called back to the testing facility and were asked if there was a barn in the
movie. 17% of the respondents to the first question said yes, compared to only
3 % for the second question.
We can carry this example into accident investigation. If we have been told by
one party that there was a pedestrian close to the accident scene, we may ask
a driver questions such as “How fast were you going when you passed the
pedestrian”. If later information then reveals that there was no pedestrian, we
may still have planted the memory of a pedestrian in the mind of the driver,
which may cause him/her to adjust the accident narrative to account for the
pedestrian.
Now, these examples are provided here not to scare investigators off from
interviewing or to create mistrust in interviewing as a source for information.
Interviews, on the contrary, are usually by far the most important source for
information about why the accident occurred. In previous investigations made
by Chalmers Accident Investigation Team, drivers have generally been very
honest and forthcoming when interviewed about the accident, especially once
they are made aware that the interview is for safety research, and that they will
remain anonymous in all accident descriptions. However, it pays off to be aware
of what people can be expected to reliably describe, as well as the possible
traps that we may create for ourselves in the interview process.
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