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

Table 4

Statistical analysis of index under heavy fog condition.

Zone	Group	Speed (km/h)			Acceleration (m/s^2)
		Mean (SD)		Difference between groups	Mean (SD)		Difference between groups
Whole zone	Group ①	88.854 (14.358)	≤0.001	①-②	0.274 (0.134)	0.469	—
	Group ②	82.068 (10.248)		①-③	0.255 (0.124)
	Group ③	82.393 (13.452)			0.353 (0.144)
Clear zone	Group ①	103.267 (6.143)	≤0.001	①-②	0.245 (0.092)	≤0.001	①-②
	Group ②	99.737 (10.432)		①-③	0.163 (0.112)		①-③
	Group ③	98.481 (10.895)		②-③	0.186 (0.119)
Transition zone	Group ①	107.230 (8.223)	≤0.001	①-②	0.235 (0.191)	≤0.001	①-③
	Group ②	92.157 (10.358)		①-③	0.318 (0.254)		②-③
	Group ③	94.319 (13.514)			0.657 (0.364)
Fog zone	Group ①	70.433 (10.342)	≤0.001	①-②	0.341 (0.134)	0.001	①-②
	Group ②	64.767 (13.254)		①-③	0.284 (0.173)		①-③
	Group ③	66.643 (9.845)		②-③	0.271 (0.157)

Significant at the 95% confidence level.