Question

a) Describe what "superelevation" means for a road cross-section?

b) why is "superelevation" used in road geometrics?

Answer 1

(A) Superelevation: When there is need to provide horizontal curve, raising of outer edge of the pavement with respect to inner edge through the length of the curve is known as superelevation.

(B) Why superelevation is needed: when horizontal curve is provided in any Pavement then due to curve centrifugal force acts on the vehicle travelling on the pavement. To counteract this centrifugal force outer edge is raised that reduces the tendency of the vehicles to overturn.

As you can see in the figure wsinθ (component of weight due to superelevation) counteracts centrifugal force P.