Equilibrium Superelevation & Superelevation As Per IRC 2.16

Equilibrium Superelevation:

Equilibrium Superelevation
Equilibrium Superelevation

Note: This topic is part of the second chapter of Highway Engineering. I suggest reading this topic in the context of the complete chapter: Geometric Design of Highway. If you want to read the entire Highway Engineering, click here: Highway Engineering.

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.

eequilibrium =\(\frac{V^{2}}{127R}\) 

If the superelevation provided is less than eequilibrium 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 RoadMaximum Superelevation (emax)
Urban Road4% or 0.04
Plain & Rolling Terrain7% or 0.07
Mountainous & Steep Terrain10% 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.

Highway Engineering

1 thought on “Equilibrium Superelevation & Superelevation As Per IRC 2.16”

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top