CURVES:

 

CURVES:

Curves are provided whenever a road changes its direction or changes its alignment from up to down (vice versa). Curves are a critical! element in the pavement design. They are provided with a maximum speed limit that should lie followed very strictly.

Types of Curves:

There are two types of curves provided primarily for the comfort and ease of the motorists in the road namely:

1. Horizontal Curve
2. Vertical Curve

[1] Horizontal Curves: -Horizontal curves are provided to change the direction or alignment of a road. The sharpness of a curve increases as the radius is decrease which makes it risky and dangerous.

Types of Horizontal Curve:

(i) Simple Curve:A simple arc provided in the road to impose a curve between the two                      straight lines.

                (ii) Compound Curve: -Combination of two simple curves combined together to curve                         in the same direction.

            (iii) Reverse Curve: - Combination of two simple curves combined together to curve in                             the same direction.

            (iv) Transition Curve: - A curve that has a varying radius. It’s provided with a simple                                curve and between the simple curves in a compound curve.

[2] Vertical Curves: - Vertical curves are provided to change the slope in the road and may or may not be symmetrical. They are parabolic and not circular like horizontal curves. Identifying the proper grade and the safe passing sight distance is the main design criterion of the vertical curve.