# Crest vertical curve length

Calculate the Crest vertical curve length with our free online tool using the input parameters: Distance, Initial Grade, Final Grade, Height

Determine the necessary length of a vertical curve using this calculator. It is primarily employed during roadway design, considering scenarios where the line of sight may exceed or fall short of the curve length.

Sight Distance
Initial Roadway Grade
Final Roadway Grade
Height of driver's eye above Roadway surface
Height of object above Roadway surface
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1 Number of calculations

L_m = \frac{{A \times S^2}}{{200 \times (\sqrt{h_1} + \sqrt{h_2})^2}} \quad \forall \, S < L_m
L_m = 2S - \left( \frac{{200 \times (\sqrt{h_1} + \sqrt{h_2})^2}}{{A}} \right) \quad \forall \, S > L_m

The variables used in the formula are:

A – Absolute difference between g2 and g1

S – Sight Distance

Lm – Minimum Curve Length

h1 – Height of driver’s eye above roadway surface

h2 – Height of object above roadway surface

The calculation of a convex-shaped vertical curve is made simpler with the help of the Crest Vertical Curve Length Calculator.