A greenway is a linear space, used by the public, linking parks and other areas through a town, city, or country. It consists of paths, trails, sidewalks, and vehicle-free roadside areas in which motor vehicles are not meant to be used. Runners, cyclists, and dog walkers often take advantage of these areas, as well as anyone who wishes to safely traverse through town without a car. Ambitious greenways are built all over the world, including one along the entire eastern border of the United States. Green belts, which may be compared to large-scale greenways, are prominent in the United Kingdom.
Often, greenways appear as long dirt paths, though this is not always the case. A greenway may simply be built along the side of a road, either as a sidewalk or as part of the road itself, where motor vehicles are not meant to travel. Greenways often go through wooded areas and promote activities such as bird watching and general nature watching.
Many advantages to human health can be linked to the presence of greenways in a town or city. Such paths encourage exercises such as biking, jogging, walking, rollerskating, and similar physical activities. Additionally, when used as a mode of transportation, greenways cut down on gasoline emissions from motor vehicles, thereby reducing air pollution.
A greenway also promotes public safety. As it provides an area for hobbies such as biking and skating, there is less incentive for such activities to be conducted in streets, parking lots, or trespassed areas. These trails also provide access for disabled citizens to move about town in wheelchairs, and for dog owners to safely walk their pets in a relatively car-free area.
In 1991, an urban trail project called the East Coast Greenway was launched in the United States to connect the entire eastern border of the country. This 3,000 mile path links northern Maine to southern Florida, making use of park paths, abandoned railroads, and other various trails. Most of this greenway, however, is still on the side of roads. Only about 20 percent of the East Coast Greenway is completely traffic-free. Further development is expected to raise this percentage.
Greenways often result from regional planning policies. Large areas that adhere to such policies, known colloquially as green belts, discourage urban sprawl and urban development in respective cities, counties, states, provinces, or even entire nations. While the word "green" is often associated with the concept of environmentalism, green belts are not always established out of simple environmental concern. They also conserve historical aspects of various areas and keep populations in check. The Metropolitan Green Belt in the United Kingdom, which circles the city of London, is one of the world's largest green gelts.