A basic four-ramp interchange between a freeway and a surface street. The four diagonal ramps, one in each quadrant, suggest a diamond shape. See the Diamond page. An interchange between two freeways where access is provided by an auxiliary divided road, connected to each freeway with a trumpet interchange. Full nonstop access can be provided by this configuration, but typically a double trumpet serves a toll road, with all access to it conveniently served by a tollbooth on the access road.
Access is provided only by ramps and merges, with no stopping or turning across opposing traffic.
Compare surface street . The gore is often diagonally striped to remind traffic to stay off. Adding ramps to a grade separation, providing access from one road to another, creates an interchange. An interchange with only two diagonal ramps, one entrance and one exit, in adjacent quadrants. This interchange serves traffic to and from one direction along the freeway, but ignores the other.