Bangkok's districts often do not accurately represent the functional divisions of its neighbourhoods or land usage. Although urban planning policies date back to the commission of the "Litchfield Plan" in 1960, which set out strategies for land use, transportation and general infrastructure improvements, zoning regulations were not fully implemented until 1992. As a result, the city grew organically throughout the period of its rapid expansion, both horizontally as ribbon developments extended along newly built roads, and vertically, with increasing numbers of high rises and skyscrapers being built in commercial areas. 