A Sensor-Based Visual Effect Evaluation of Chevron Alignment Signs’ Colors on Drivers through the Curves in Snow and Ice Environment

Table 3

Evaluation of effect and speed distribution.

Curve environment	Chevrons tests (T1–T4)	Mean speed (km/h)	Standard deviation	Sample size	Mean speed difference	Pooled standard deviation	Effect size	Effect evaluation
CS	Without	65.31	12.815	120	—	—	—	—
	Red	60.50	10.049	120	4.81	11.515	0.418	Medium
	Green	60.06	10.975	120	5.25	11.930	0.440	Medium
	Blue	62.39	10.020	120	2.92	11.502	0.254	Medium
SICS	Without	38.50	10.301	100	—	—	—	—
	Red	33.32	5.389	100	5.18	8.220	0.630	Medium
	Green	35.86	8.702	100	2.64	9.535	0.277	Medium
	Blue	37.81	10.155	100	0.69	10.228	0.067	Small