Urban planning, also known as regional planning, town planning, city planning, or rural planning, is a technical and political process that focuses on the development and design of land use and the built environment, including air, water, and infrastructure that passes through and out of urban areas, such as a ring of highways. Urban planning is considered to be an essential component in creating livable cities. The major elements of urban planning are community involvement, coordination, and cooperation. Community involvement refers to seeking input from residents about what kind of community they want to live in and how it should be developed. This involves both informal and formal processes for communication between government officials and their constituents. Coordination between different agencies responsible for regulating land use, such as local governments and the state or federal government, helps avoid conflicting policies that can lead to litigation or inaction on any one issue. Cooperation among these various agencies facilitates this effort by reducing conflict between them and providing an opportunity for them to share information. Planning practices range from simple zoning codes that regulate the use of land within a community's boundaries to more comprehensive plans that address issues such as transportation systems, environmental protection, and community facilities. Some cities with small populations may have planning departments that carry out all or most of these functions independently, while others may contract with a private firm or group of individuals to perform planning services.