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Vertical Road Curves - Coggle Diagram
Vertical Road Curves
Stopping Side Distance (SSD)
Crest
From driver's eyes to object on the other curve over the crest
SSD longer than the length of the curve between 2 cars
H1=height of driver's eyes (0.92m)
H2=height of object (0.15m)
Sag
From headlight beam to the object on other curve
SSD longer than the length of the curve between 2 cars
H=height of headlight
B=inclined angle of headlight beam
Refer to JKR's standard
Curve length
Crest
SSD>L
L=2SSD-(200((√H1)+(√H2))^2)/(P-Q)
SSD<L
L=((P-Q)SSD^2)/(200((√H1)+(√H2))^2)
OSD<L
L=((P-Q)OSD^2)/(200((√H1)+(√H2))^2)
OSD>L
L=2OSD-(200((√H1)+(√H2))^2)/(P-Q)
Sag
SSD>L
L=2SSD-(200(H+SSD tan B))/(P-Q)
SSD<L
L=((P-Q)SSD^2)/(200(H+SSD tan B))
Overtaking Side Distance (OSD)
H1=height of driver's eyes(0.92m)
H2=1.32m
Rate of Curvature, K
L=K(p-q)
Horizontal forward distance measured on the curve that give rise to 1 % change in slope
LER KEE HONG (A19EA0055)