San José has taken to heart a report by the State of California that compared "traditional" building costs with "green" building costs and found that an up-front investment of less than two percent of construction costs yields a life cycle savings of over 10 times the initial investment. With that in mind, in 2001 San José formally adopted Green Building policies including San José LEED (Leadership in Energy and Environmental Design). These are based on the U.S. Green Building Council’s rating system, but also incorporate specific City policies including urban runoff and water conservation. In May 2003, San José’s West Valley Branch Library was the first "Green" building to officially open. As part of the city's airport improvement plans, the North Concourse will be built as a green building, as will San José's new City Hall currently under construction in the downtown center and scheduled to open in 2005. Although San José's new City Hall design began well before the City's Green Building policy development, the project's goal is to incorporate as many green building features as feasible for maximize sustainability.