Hazard anticipation of young novice drivers - SWOV

4.2.3. Procedure
On arrival, the experimenter explained to participants orally what the study
in general was about (but not the hypotheses) and what they were going to
do. Thereafter participants completed the questionnaire. The questionnaire
also contained general information about the study. Participants then were
seated in front of the monitor of the eye tracker and the eye tracker was
calibrated to the eyes of the participant. This lasted no longer than one
minute. Afterward, participants started either with the hazard detection and
recognition task (the video clips) or the risk assessment and action selection
task (the photographs). The order of these two tasks was counter balanced
across participants. However, the order of the videos and the photographs
within each task were fixed. With the software of the eye tracker no interim
changes of the order within a task could be made. After these two tasks,
participants did the visual perception test (the MVPT-3). This test was
always completed at the end of the test session as this test did not require the
use of an eye tracker. Finally, participants were paid for their participation.
The total duration of a test session was approximately one hour.
4.2.4. Data processing and design
The hazard detection and recognition task
With the aid of two experts of CBR, for each latent hazard in the video clips
the timeframe was established in which a fixation on the latent hazard of at
least 200 ms (the minimum fixation duration supposed to be necessary to
process information, see Section 4.1.4) was either not to soon or not too late
for evasive actions, should the latent hazard have materialized. Thereafter,
within these timeframes the area was defined the fixation or fixations had to
be. In case of the overt latent hazard this area was the visible other road user
that could start to act dangerously and in case of a covert latent hazard this
was the area from where another road user on collision course could emerge.
The coordinates and the size of these areas change while the video runs. As
the eye tracker recorded the coordinates of fixations and the duration of
fixations, but not the coordinates of the moving Areas Of Interest (AOIs) on
the screen, the coordinates of the relevant areas had to be determined video
frame by video frame. The data of the eye tracker were combined with the
data of the coordinates of the areas. Of each area was established if a
participant had a fixation of at least 200 ms on the latent hazard within the
timeframe. If there was at least one correct fixation, the timestamp of the
beginning of the first fixation, the duration of this fixation, the timestamp of
the last fixation and the duration of this fixation, the total number of the
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