# Crest vertical curve length

Calculate the minimum curve length required for the vertical curve. This calculator is mainly used while designing the roadways in which the sight distance can be greater or less than the curve length.

## Calculator of crest vertical curve length on roadways

## Formula of crest vertical curve length

L_{m} = ( A×S² ) / ( 200 × (√h_{1} + √h_{2})² ) ∀ S<L_{m}

L_{m} = 2S − { ( 200 × (√h_{1} + √h_{2})² ) / A } ∀ S>L_{m}

- A – absolute difference between g
_{2}and g_{1} - S – sight distance
- L
_{m}– minimum curve length - h
_{1}– height of driver’s eye above roadway surface - h
_{2}– height of object above roadway surface

**Note**. This statistical crest vertical curve length calculator is provided for your personal use and should be used as a guide only. Roadways and other decisions should NOT be based on the results of this calculator. Although this calculator has been tested, we cannot guarantee the accuracy of its calculations or results.