In England and Wales, the Republic of Ireland, Hong Kong[1] and some Commonwealth countries (such as Canada, South Africa, Australia and New Zealand), the term subway normally refers to a specially constructed underpass for pedestrians and/or cyclists beneath a road or railway, allowing them to reach the other side in safety.
The term is also used in the United States, for example, by the California Department of Transportation, for a road undercrossing which is depressed.[2][3]
The term is also used in parts of Pennsylvania in the United States, such as Harrisburg, Duncannon and Wyoming County.[4][5][6]
Underground pedestrian passageways are less common in North American cities than in European cities of comparable size. They are constructed when it is necessary for pedestrians to cross a railroad or a limited-access highway such as an interstate highway, and of course they appear at the exits from underground rapid transit systems, but one would be rarely built just to enable people to cross an ordinary city street. When they are built, the term pedestrian underpass is more likely to be used, since the word "subway" is usually used there to refer to rail-based rapid transit systems such as New York Subway in the United States.
In the Philippines, it can be seen in the city of Makati and some places in Manila, such as in Quiapo and near the Manila City Hall, commonly known as "Lagusnilad."
Subways may also be constructed for the benefit of wildlife.