INTERCHANGE

grade-separated intersections are provided to separate the traffic in the vertical grade. When a railway line crosses a road, then grade separators are used. Different types of grade-separators are flyovers and interchange. Flyovers itself are subdivided into overpass and underpass. When two roads cross at a point, if the road having major traffic is elevated to a higher grade for further movement of traffic, then such structures are called overpass. Otherwise, if the major road is depressed to a lower level to cross another by means of an under bridge or tunnel, it is called under-pass.

Interchange is a system where traffic between two or more roadways flows at different levels in the grade separated junctions. Common types of interchange are:

• Directional interchange;

• Trumpet interchange;

• Diamond interchange; and

• Cloverleaf interchange