Banking of road:
The process of raising outer edge of a road over its inner edge through certain angle is known as banking of road.
Necessity of banking of the road:
i. When a vehicle moves along horizontal curved road, necessary centripetal force is supplied by the force of friction between the wheels of vehicle and surface of road.
ii. Frictional force is not enough and unreliable every time as it changes when road becomes oily or wet in rainy season.
iii. To increase the centripetal force the road should be made rough. But it will cause wear and tear of the tyres of the wheel.
iv. Thus, due to lack of centripetal force vehicle tends to skid.
v. When the road is banked, the horizontal component of the normal reaction provides the necessary centripetal force required for circular motion of vehicle.
vi. Thus, to provide the necessary centripetal force at the curved road, banking of road is necessary.