The terms road link, road interchange, road junction, road junction, road distributor, or road interchange,[1]​ are used in the field of road transport to define the intersections of two or more roads where at least one of them has a crossing at a different level and one or more access ramps, in such a way that the traffic of at least one of the roads can cross the link without directly crossing any other traffic flow. This differs from conventional intersections, where roads intersect at the same level. Interchanges are always used when one of the roads is a controlled access road, such as a highway or expressway, although they are also used on high-capacity roads to replace at-grade intersections.

For the following definitions, it is considered that driving is carried out on the right side of the road (especially in everything related to the directions of turn and sides of the road). For those road systems in which you drive on the left side, the terms left and right must be interchanged. On multi-lane roads, it is considered that slower vehicles are obliged to circulate preferably on the right side of the road, a circumstance that is used to facilitate vehicle exit and entry maneuvers.

Normally the types of links described correspond to the connection of two main roadways. When more than two main routes must be connected or there are roadways parallel to the main trunks, the solutions adopted can become extraordinarily complicated.

Three way links

"Trumpet" type interchanges are commonly used to link one highway or road that ends at another. This involves at least one loop ramp connecting incoming or outgoing traffic to the terminating roadway with the continuing freeway.

This type of link is very useful for highways, roads and toll roads, since it concentrates all traffic at a single point, where toll booths can be installed. Double trumpet connections are common in places where a toll road meets another free access road. They can also be useful when most of the traffic on the ending highway goes in a certain direction, leaving the loop ramp for turns with less traffic. They have the advantage of being cheaper connections, having fewer structures and occupying less land than other types of links. They are very useful when the traffic towards the secondary road is not very high. With greater traffic the link does not work well and it is necessary to resort to direct links.