Stack interchange

A directional interchange, colloquially known as a stack interchange, is a type of grade-separated junction between two controlled-access highways that allows for free-flowing movement to and from all directions of traffic. These interchanges eliminate the problems of weaving, have the highest vehicle capacity, and vehicles travel shorter distances when compared to different types of interchanges.

The first directional interchange built in the world was the Four Level Interchange in Los Angeles; it was constructed in 1949 and put into full use in 1953.