Controlled-access highway

A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway and expressway. Other similar terms include ''

throughway A thoroughfare is a primary passage or way as a transit route through regularly trafficked areas, whether by road on dry land or, by extension, via watercraft or aircraft. On land, a thoroughfare may refer to anything from a multi- lane hi ...

'' and ''

parkway A parkway is a landscaped thoroughfare.''"parkway."''Webster's Third New International Dictionary, Unabridged. Merriam-Webster, 2002. http://unabridged.merriam-webster.com (14 Apr. 2007). The term is particularly used for a roadway in a park or ...

''. Some of these may be limited-access highways, although this term can also refer to a class of highways with somewhat less isolation from other traffic. In countries following the Vienna convention, the motorway qualification implies that walking and parking are forbidden. A fully controlled-access highway provides an unhindered flow of traffic, with no traffic signals,

intersections In mathematics, the intersection of two or more objects is another object consisting of everything that is contained in all of the objects simultaneously. For example, in Euclidean geometry, when two lines in a plane are not parallel, their ...

or property access. They are free of any at-grade crossings with other roads, railways, or pedestrian paths, which are instead carried by

overpass An overpass (called an overbridge or flyover in the United Kingdom and some other Commonwealth countries) is a bridge, road, railway or similar structure that crosses over another road or railway. An ''overpass'' and ''underpass'' together form ...

es and underpasses. Entrances and exits to the highway are provided at interchanges by slip roads (ramps), which allow for speed changes between the h