Safety Evaluation of Fog Warning Systems in a Connected Vehicle Environment Based on Sample Entropy

Table 2

Statistical analysis of index under no fog condition.

Zone	Group	Speed (km/h)			Acceleration (m/s^2)
		Mean (SD)		Difference between groups	Mean (SD)	P	Difference between groups
Whole zone	Group ①	105.672 (4.690)	0.011	①-②	0.195 (0.097)	0.025	①-③
	Group ②	107.265 (5.757)			0.183 (0.105)
	Group ③	106.443 (5.851)			0.139 (0.104)
Clear zone	Group ①	100.452 (2.943)	0.017	①-②	0.202 (0.115)	0.011	①-③
	Group ②	102.869 (6.577)			0.249 (0.131)
	Group ③	101.253 (6.355)			0.187 (0.108)
Transition zone	Group ①	108.192 (4.645)	≤0.001	①-②	0.120 (0.100)	0.001	①-③
	Group ②	111.727 (6.581)		①-③	0.164 (0.139)		②-③
	Group ③	109.499 (3.417)		②-③	0.103 (0.009)
Fog zone	Group ①	109.322 (4.937)	0.013	①-②	0.209 (0.139)	0.612	—
	Group ②	109.804 (5.410)		①-③	0.137 (0.113)
	Group ③	109.946 (3.913)			0.126 (0.095)

Significant at the 95% confidence level.