1 Introduction
1.1 Definition of Relevant Constructs
1.1.1 Objective Complexity
1.1.2 Subjective Complexity
1.1.3 Familiarity with a Situation
1.2 Research Questions and Hypotheses
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H1.1: The perceived complexity of a situation declines with a rise in familiarity due to repetition of the situation.
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H1.2: Higher familiarity with a situation leads to shorter action decision times.
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H1.3: The influence of situation familiarity on the action decision time is mediated by the perceived complexity of a situation.
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H2.1: More relevant vehicles in the traffic environment lead to an increased subjective complexity during a takeover.
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H2.2: In a more complex driving environment, drivers need more time to update their situation awareness model and thus make a later action decision.
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H2.3: The influence of the objective complexity on the time to make an action decision is mediated by the subjective complexity of the situation.
2 Methods
2.1 Simulator
2.2 Study Design
2.3 Scenarios
2.4 Variables and Measurement
2.4.1 Situation Familiarity
2.4.2 Objective Traffic Complexity
2.4.3 Subjective Complexity
2.4.4 Time to Action Decision
2.5 Procedure
2.6 Statistical Evaluation
3 Results
3.1 The relation between Situation Familiarity and the Subjective Complexity (H1.1)
Subjective complexity | Situation familiarity | ||
---|---|---|---|
β | t(358) | R2 | |
Total | -0.83 | -4.34 | 0.05 *** |
Mental Demand | -0.85 | -3.23, | 0.03 ** |
Temporal Demand | -0.85 | -3.04, | 0.02 ** |
Physical Demand | -0.28 | -1.7, | 0.01 . |
Performance | -1.08 | -3.85, | 0.04 *** |
Effort | -0.7 | -2.86, | 0.02 ** |
Frustration | -1.21 | -5.41, | 0.07 *** |
3.2 The relation between Situation Familiarity and the Time to Action Decision (H1.2)
Situation Familiarity | Time to action decision | ||||
---|---|---|---|---|---|
Min | Median | Mean | Max | SD | |
1 | 3.117s | 6.176s | 7.907s | 24.768s | 4.6 |
2 | 2.566s | 4.834s | 6.425s | 21.51s | 3.79 |
3 | 2.900s | 4.567s | 5.675s | 21.602s | 2.96 |
3.3 Subjective Complexity as Mediator between the influence of Situation Familiarity on the Time until an Action Decision is made (H1.3)
3.4 The relation between Objective Complexity and Subjective Complexity (H2.1)
Subjective Complexity | Objective traffic complexity | ||
---|---|---|---|
β | t(358) | R2 | |
Total | 0.55 | 6.92 | 0.12 *** |
Mental Demand | 0.79 | 7.27 | 0.13 *** |
Temporal Demand | 0.88 | 7.72 | 0.14 *** |
Physical Demand | 0.27 | 3.92 | 0.04 *** |
Performance | 0.36 | 2.94 | 0.02 ** |
Effort | 0.56 | 5.48 | 0.07 *** |
Frustration | 0.45 | 4.59 | 0.05 *** |
3.5 The relation between Objective Complexity and the Time to Action Decision (H2.2)
Relevant Vehicles | Time to action decision | ||||
---|---|---|---|---|---|
Min | Median | Mean | Max | SD | |
0 | 2.734 s | 6.567 s | 7.422 s | 23.269 s | 4.29 |
1 | 2.566 s | 5.601 s | 6.476 s | 21.401 s | 3.15 |
2 | 3.233 s | 4.850 s | 5.823 s | 24.768 s | 2.76 |
3 | 3.233 s | 4.875 s | 6.139 s | 23.952 s | 3.97 |
6 | 2.900 s | 5.800 s | 8.733 s | 22.701 s | 5.52 |