Changes in Trust after Driving Level 2 Automated Cars
Table 1
Questionnaire results. A Friedman test was performed for an analysis of the variances of m0 (measurement 0), m1 (measurement 1), and m2 (measurement 2). Wilcoxon Signed Ranks test was used for pairwise comparisons (i.e., m0 versus m1, m0 versus m2, and m1 versus m2); (p <= .004).
N = 106
Scenario
Missing values
Friedman test
M0 (M, SD)
M1 (M, SD)
M2 (M, SD)
M0 vs m1
M0 vs m2
M1 vs m2
(1) You are driving on a highway with an average amount of traffic. The system is set to automatically keep distance from the vehicle in front, and to keep within the lane.
4
χ2 = 23.096, p < .001
M = 4.21, SD = 1.09
M = 4.62, SD = 0.76
M = 4.43, SD = 0.92
Z = -3.927, p < .001
Z = -2.511, p = .012
Z = -2.360, p = .018
(2) You drive on the highway and the vehicle in front brakes hard.
3
X2 = 26.315, p < .001
M = 3.49, SD = 1.18
M = 4.04, SD = 0.99
M = 3.87, SD = 1.06
Z = -4.014, p < .001
Z = -3.390, p = .001
Z = -2.024, p = .043
(3) A car overtakes you in the right lane.
1
X2 = 2.537, p = .281
M = 3.55, SD = 1.07
M = 3.67, SD = 1.27
M = 3.60, SD = 1.12
Z = -1.065, p = .287
Z = -.444, p = .657
Z = -.676, p = .499
(4) You drive on the highway with a lot of rain, so the visibility is poor.
0
X2 = 6.483, p = .039
M = 2.96, SD = 1.18
M = 2.57, SD = 1.07
M = 2.71, SD = 1.15
Z = -3.390, p = .001
Z = -2.212, p = .027
Z = -1.484, p = .138
(5) You drive in a work area with yellow road marking in addition to the normal white road marking.
2
X2 = 8.130, p = .017
M = 2.01, SD = 0.91
M = 1.85, SD = 0.95
M = 1.80, SD = 0.89
Z = -1.883, p = .06
Z = -2.211, p = .027
Z = -0.668, p = .504
(6) A car merges in from the right lane and has a much lower speed than yours.
1
X2 = 0.087, p = .957
M = 3.24, SD = 1.14
M = 3.24, SD = 1.15
M = 3.26, SD = 1.23
Z = -.092, p = .926
Z = -.327, p = .744
Z = -.235, p = .814
(7) A deer suddenly crosses the highway – a situation in which normally you would brake.
1
X2 = 19.196, p < .001
M = 2.69, SD = 1.21
M = 2.20, SD = 1.16
M = 2.08, SD = 1.14
Z = -3.437, p = .001
Z = -4.026, p < .001
Z = -1.233, p = .218
(8) The lane where you drive ends, you need to insert the lane to your right.
0
X2 = 31.848, p < .001
M = 2.93, SD = 1.10
M = 2.23, SD = 1.18
M = 2.24, SD = 1.17
Z = -4.658, p < .001
Z = -4.641, p < .001
Z = -0.329, p = .742
(9) You are approaching a curve on the highway.
4
X2 = 48.771, p < .001
M = 3.63, SD = 1.10
M = 2.81, SD = 1.37
M = 2.52, SD = 1.30
Z = -5.239, p < .001
Z = -6.326, p < .001
Z = -2.556, p = .011
(10) You are driving on the highway behind a motorbike instead of behind a car.
1
X2 = 13.076, p = .001
M = 3.5, SD = 1.17
M = 3.43, SD = 1.20
M = 3.15, SD = 1.17
Z = -0.578, p = .564
Z = -3.003, p = .003
Z = -2.970, p = .003
(11) You are driving on the highway and the speed limit decreases. Your speed should adapt to the new speed limit.
