An interchange a place where two freeways meet, or where a freeway and another road meet. An interchange has two levels so traffic going through does not meet. Different levels are connected by ramps. There are many different types of freeway interchanges. The two most common types of freeway interchanges are the diamond interchange and the cloverleaf interchange:
- A diamond interchange has four ramps that enter and leave the freeway at a small angle and meet the non-freeway at almost right angles. These ramps at the non-freeway can be controlled through stop signs or traffic signals. The name comes from the diamond-like shape.
- A cloverleaf interchange has eight ramps that handle all traffic without stop signs or traffic lights. To turn left, traffic goes in a 270° turn. The name comes from the four-leaf clover-like shape.