Q1: For the movement of vehicles at an intersection of two roads, without any interference, the type of grade separator generally preferred to, is

ANS:D - clover leaf.

1. Diamond Interchange:
Diamond interchanges are used where two highways cross with each other. It contains 4 legs of direct interchange ramps in 4 quadrants of the junctions as shown in the image below.

2. Trumpet Interchange:
Trumpet interchanges are constructed where one highway terminates at another highway as shown in the figure. It contains three legs at the end, two of them are direct interchange ramps and another one is a loop ramp which is a combination of semi-direct and indirect interchange ramps. This is also called as a three-leg interchange.

3. Cloverleaf Interchange:
Cloverleaf interchanges contain 4–legs and eight ramps. In each quadrant, one direct interchange ramp and one indirect interchange ramp is provided as shown in the figure. This type of interchange fulfils all the requirements for the complete separation of traffic. Cloverleaf interchanges are used at intersections where two major highways cross each other.

4. Partial Cloverleaf Interchange:
The partial cloverleaf interchange is the modification of the cloverleaf interchange. It also contains 4 legs but with fewer loop ramps than the cloverleaf interchange as shown below.

5. Rotary Interchange:
Rotary interchange is provided at circular junctions where traffic is permitted to flow in one direction around Central Island and one road axis is raised above the rotary intersection to allow grade separation.

6. Stack Interchange:
Stack interchange also called directional or free-flow interchange contains multiple levels of grade separations as shown in the figure.