Table 3. Descriptive statistics of design features as a function of sign category.

Sign category	Design features	Mean	Standard deviation	Coefficient of variation	Maximum	Minimum
Mandatory	Familiarity	65.34	10.07	15.41	86.77	38.71
	Concreteness	79.64	6.03	7.57	93.00	66.00
	Simplicity	80.13	5.89	7.46	92.26	63.87
	Meaningfulness	75.63	6.26	8.27	88.06	62.26
	Semantic closeness	79.21	7.67	9.68	94.52	60.65
Prohibition	Familiarity	63.16	11.76	18.61	87.78	31.67
	Concreteness	75.01	8.11	10.81	93.00	54.00
	Simplicity	74.70	8.19	10.96	89.44	50.56
	Meaningfulness	70.77	9.04	12.77	92.78	42.78
	Semantic closeness	71.94	8.81	12.24	91.67	50.56
Warning	Familiarity	66.76	18.43	27.60	81.00	18.00
	Concreteness	75.90	15.91	20.96	84.10	33.00
	Simplicity	76.43	16.76	21.92	82.30	22.50
	Meaningfulness	70.04	18.58	26.52	76.60	20.00
	Semantic closeness	73.95	17.20	23.25	83.00	25.00