Why are railway tracks and highways banked on the curves ?

Q: Why are railway tracks and highways banked on the curves ?

Ans: When a road is banked , the normal reactions on the wheels give rise to component forces towards the center of the path , which is essential for the maintenance of the motion of a vehicle in a circular path . In the absence of banking the necessary centripetal force is provided by lateral pressure on the outer wheels . This involves wear and tear of tyres or wheels , in addition to chances of accidents at high speeds .