A controlled-access highway is a type of highway which has been designed for high-speed vehicular traffic, with all traffic flow and ingress/egress regulated. Common English terms are freeway, motorway and expressway, other similar terms include Interstate and parkway. Some of which may be limited-access highways, although this term can refer to a class of highway with somewhat less isolation from other traffic. In countries following Vienna convention, the motorway qualification implies they are forbidden for walking or parking, a controlled-access highway provides an unhindered flow of traffic, with no traffic signals, intersections or property access. They are free of any at-grade crossings with roads, railways, or pedestrian paths. Entrances and exits to the highway are provided at interchanges by slip roads, on the controlled-access highway, opposing directions of travel are generally separated by a median strip or central reservation containing a traffic barrier or grass. Elimination of conflicts with other directions of traffic dramatically improves safety and capacity, controlled-access highways evolved during the first half of the 20th century. Italy opened its first autostrada in 1924 connecting Milan to Varese, Germany began to build its first 30-kilometre autobahn controlled-access highway without speed limits in 1932 between Cologne and Bonn. It then rapidly constructed a system of such roads in anticipation of their use in the Second World War. The first North American freeways opened in the New York City area in the 1920s, Britain, heavily influenced by the railways, did not build its first motorway, the Preston By-pass, until 1958. Most technologically advanced nations feature a network of freeways or motorways to provide high-capacity urban travel, or high-speed rural travel. Many have a national-level or even international-level system of route numbering, exit is marked with another symbol. The definitions of motorway from the OECD and PIARC are almost identical, british Standards Motorway, Limited-access dual carriageway road, not crossed on the same level by other traffic lanes, for the exclusive use of certain classes of motor vehicle. ITE Freeway, A divided major roadway with full control of access and this definition applies to toll as well as toll-free roads. Freeway A, This designates roadways with greater complexity and high traffic volumes. Usually this type of freeway will be found in areas in or near the central core. Freeway B, This designates all other divided roadways with full control of access where lighting is needed, principal arterials may cross through urban areas, serving suburban movements. The traffic is characterized by high speeds and full or partial access control, other roads leading to a principal arterial are connected to it through side collector roads
The interchange between US-131, M-6 and 68th Street in Wyoming, Michigan, shows many of the features of controlled-access highways—opposing traffic on separate carriageways, no at-grade intersections and no direct access to properties.
The A10 near Orléans, France showing hard shoulder and emergency telephone. The broken demarcation line for the hard shoulder is specific to France, and serves as a safety reference mark for drivers: the advisory distance from the vehicle ahead is two dashes minimum.
De Lucht Rest Area on the Dutch A2 - A typical rest area in the Netherlands with services (fuel, refreshments and toilets). The only access is via the highway that it serves.