
- 66 -
A roadway can be described as a Horizontal curve and a
Vertical curve. We describe a horizontal element by line
、
circle
、
spiral and point of intersection, these shape have some attribute
as follow:
Attribute of cirle and spiral
Attribute of point of intersection
Length of line
Azimuth
Line
Length of arc
radius
PT
A1
A2
R
Entrance point PT0
Exit point PT1