page_title: Grade separation
hierarchical_section_title: Grade separation
caption_attribution_description: English: A view of the Circle Interchange from the Willis Tower in 2018. Photo by Chris6d.
context_page_description: In civil engineering, grade separation is a method of aligning a junction of two or more surface transport axes at different heights so that they will not disrupt the traffic flow on other transit routes when they cross each other. The composition of such transport axes does not have to be uniform; it can consist of a mixture of roads, footpaths, railways, canals, or airport runways. Bridges, tunnels, or a combination of both can be built at a junction to achieve the needed grade separation.
  In North America, a grade-separated junction may be referred to as a grade separation or as an interchange – in contrast with an intersection, at-grade, a diamond crossing or a level crossing, which are not grade-separated.
context_section_description: In civil engineering (more specifically highway engineering), grade separation is a method of aligning a junction of two or more surface transport axes at different heights (grades) so that they will not disrupt the traffic flow on other transit routes when they cross each other. The composition of such transport axes does not have to be uniform; it can consist of a mixture of roads, footpaths, railways, canals, or airport runways. Bridges (or overpasses, also called flyovers), tunnels (or underpasses), or a combination of both can be built at a junction to achieve the needed grade separation.
  In North America, a grade-separated junction may be referred to as a grade separation or as an interchange – in contrast with an intersection, at-grade, a diamond crossing or a level crossing, which are not grade-separated.
caption: An example of the potential complexity of grade separation, seen in the Jane Byrne Interchange in Chicago
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