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Hazard anticipation of young novice drivers - SWOV

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Discussion about fixated latent hazards and mentioned latent hazards<br />

Fixations on overt latent hazards can be the result <strong>of</strong> different mechanisms.<br />

Firstly as was noted before, in situations with overt latent hazards a fixation<br />

on another road user is possible without having any expectations that this<br />

other road user may start to act dangerously. Secondly, a fixation can be the<br />

result <strong>of</strong> a bottom-up process, but after having 'seen' that other road user<br />

more or less accidentally, a driver may realize that this other road may start<br />

acting dangerously in the given circumstances. This is to say that a bottomup<br />

fixation or a top-down fixation not related to hazard perception has led to<br />

the activation <strong>of</strong> the proper schema for noticing the overt latent hazard.<br />

Thirdly, a fixation on another road user can be purely the result <strong>of</strong> a topdown<br />

process related to hazard <strong>anticipation</strong>. A saccade then is made in the<br />

direction <strong>of</strong> the other road user with the intention to fixate (keep an eye on)<br />

this other road user because, based the activated dominant schema, it is<br />

expected that in situations like this, particular road users may show<br />

dangerous behaviour. These top-down fixations can be automatic when it is<br />

a routine overt latent hazard and can be controlled when it is a discovered<br />

new type <strong>of</strong> overt latent hazard.<br />

In the first situation, participants will not mention the overt latent<br />

hazard because for them there was no overt latent hazard. In the second and<br />

third situation, participants may mention the hazard only when this overt<br />

hazard was a serious possible threat for them. In none <strong>of</strong> the video clips the<br />

latent hazards developed into an imminent hazard that required immediate<br />

action to avert a crash. When the risk assessment by the participants was low<br />

and the overt latent hazard did not materialize, it is likely that the overt<br />

latent hazard was immediately forgotten and therefore not mentioned,<br />

especially when the latent hazards were 'routine hazards' that did not require<br />

involvement <strong>of</strong> the SAS (see Section 3.8 and Section 4.1.6). This could explain<br />

why the percentages mentioned overt latent hazards were also lower than<br />

the percentages fixated overt latent hazards for the group <strong>of</strong> experienced<br />

<strong>drivers</strong>.<br />

In contrast to fixations on overt latent hazards, fixations on covert latent<br />

hazards are very likely only top-down and related to hazard <strong>anticipation</strong>, as<br />

there has to be a reason why <strong>drivers</strong> look in directions where at the<br />

particular nothing special can be seen. One can argue that fixated covert<br />

hazards that are not mentioned, are more <strong>of</strong>ten automated top-down<br />

fixations. If this is the case, fixations are made based on the dominant schema<br />

that was selected within the CS, without involvement <strong>of</strong> the SAS (the gray<br />

arrow from 'Competitive selection' to 'Gaze control' in Figure 4.1). As these<br />

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