**Equilibrium Superelevation:**

Equilibrium superelevation is that superelevation at which pressure at the inner and outer tyre will be equal. if the coefficient of friction is neglected i.e. f =0 then,

e=\(\frac{V^{2}}{127R}\) , V in km/h

This means that if a road surface is super elevated by tan^{-1}\(\frac{V^{2}}{127R}\) then the friction force will not be called upon to act and thus the pressure on both the wheel will be equal.

e_{equilibrium} =\(\frac{V^{2}}{127R}\)

If the superelevation provided is less than e_{equilibrium} lateral fiction will come into play and will go on increase as the superelevation gets reduced.

**Note⇒ Due to equilibrium superelevation:**

- No overturning, No Toppling, No Skidding, No Sliding.
- Pressure at the inner and outer tyre will be equal.

**Superelevation As Per IRC**

**1.Maximum Superelevation**

Type of Road | Maximum Superelevation (e_{max}) |

Urban Road | 4% or 0.04 |

Plain & Rolling Terrain | 7% or 0.07 |

Mountainous & Steep Terrain | 10% or 0.10 |

**2.The minimum superelevation**

**It is provided on a road must not be less than the camber of the road for the adequate drainage of water from the surface.**

For Detailed Analysis of Highway Engineering Step By Step.

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