Table 2.

Summary driving characteristics per day (mean and standard deviation or percentages are presented)

Variable	Total	Intact	MCI	p-value
N	28	21	7
Mean # of (one-way) trips per day	4.2 (1.0)	4.1 (0.9)	4.7 (1.4)	0.19
Day-to-day variability in # of trips	2.1 (0.6)	2.1 (0.5)	2.3 (0.8)	0.49
Mean distance driven per day (miles)	20 (13)	22 (13)	14 (11)	0.06
Day-to-day variability in distance driven	26 (17)	31 (17)	13 (12)	0.01*
Mean time driven per day (h)	0.9 (0.4)	0.9 (0.4)	0.8 (0.4)	0.26
Day-to-day variability in time driven	0.7 (0.3)	0.8 (0.3)	0.5 (0.2)	<0.01**
Mean first clock start time of driving per day	11.06 (1.2)	11.18 (1.2)	10.36 (1.4)	0.43
Day-to-day variability in first start time (h)	2.8 (0.8)	2.8 (0.6)	2.7 (1.1)	0.78
Mean last clock start time of driving per day	15.4 (1.6)	15.2 (1.4)	15.9 (1.9)	0.33
Day-to-day variability in last start time (h)	3.2 (0.6)	3.2 (0.6)	3.2 (0.8)	0.79
Mean # of days monitored	206 (36)	208 (38)	201 (33)	0.70
% of days at least one trip was taken out of all days monitored	52%	49%	60%	0.21
% of driving days with ≥20 miles driven	26%	27%	21%	0.51
Mean time of highway driving per day (s)	450 (506)	543 (533)	172 (288)	0.01*
Mean time of nighttime driving per day (s)	227 (323)	191 (194)	337 (571)	0.81
Mean # left turns per day	8.2 (3.2)	7.9 (3.3)	9.2 (3.0)	0.35
Mean # right turns per day	9.9 (3.9)	9.6 (4.1)	10.9 (3.0)	0.43
Mean time driving over 70 mph from day (s)	38 (60)	44 (62)	21 (53)	0.24
Mean # of hard breaks per day	1.2 (0.9)	1.3 (0.9)	0.7 (0.6)	0.09
Mean # of hard accelerations per day	0.8 (0.8)	0.8 (0.9)	0.7 (0.7)	0.83
Self-reported driving habits
Drives five or more round trips per week (%)	39%	33%	57%	0.38
Drives 20 or more miles per week (%)	64%	67%	57%	0.67
Drives on highway three or more times per week (%)	43%	43%	43%	1.0

^*p < 0.05;

^**p < 0.01; p = 0.05/23 = 0.0022 after adjusting for multiple comparisons.