Table 7. Widening standards by radius of curve and internal angle.

Radius of curve	Internal angle
	<90°	90∼135°	135°≤
12 m	1.70	1.50	1.25
13 m	1.50
14 m		1.25	1.00
15 m	1.25
16 m		1.00
17 m	1.00
18 m			0.75
19 m
20 m	0.75	0.75
21 m
22 m
23 m			0.50
24 m		0.50
25 m	0.50