Research Article
Drivers’ Interaction with Adaptive Cruise Control on Dry and Snowy Roads with Various Tire-Road Grip Potentials
Table 4
Drivers’ self-ratings of workload, comfort, safety, and trust related to driving with different time gaps of the ACC (
).
| Subjective variable | ACC GAP | Mean | SD | 95% confidence interval | Lower limit | Upper limit |
| Mental Demand | 1 second | −2.48 | 0.23 | −2.94 | −2.03 | 1.8 seconds | −2.82 | 0.23 | −3.27 | −2.38 | Physical Demand | 1 second | −3.16 | 0.21 | −3.58 | −2.75 | 1.8 seconds | −3.25 | 0.20 | −3.65 | −2.85 | Temporal Demand | 1 second | −3.13 | 0.20 | −3.52 | −2.73 | 1.8 seconds | −3.30 | 0.20 | −3.70 | −2.91 | Performance | 1 second | 2.33 | 0.25 | 1.84 | 2.83 | 1.8 seconds | 2.29 | 0.28 | 1.74 | 2.84 | Effort | 1 second | −2.54 | 0.24 | −3.01 | −2.06 | 1.8 seconds | −2.84 | 0.23 | −3.30 | −2.38 | Frustration | 1 second | −2.92 | 0.25 | −3.42 | −2.43 | 1.8 seconds | −3.41 | 0.20 | −3.81 | −3.01 | Comfort | 1 second | 4.64 | 0.12 | 4.40 | 4.88 | 1.8 seconds | 5.09 | 0.10 | 4.89 | 5.26 | Safety | 1 second | 4.14 | 0.15 | 3.85 | 4.43 | 1.8 seconds | 4.95 | 0.12 | 4.72 | 5.18 | Trust | 1 second | 4.17 | 0.15 | 3.87 | 4.46 | 1.8 seconds | 4.72 | 0.12 | 4.48 | 4.96 |
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Note: ranges of the scales are specified in Section 2.4.
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