Infill development occurs in locations where some development has already taken place and infrastructure is already in place. In urban areas, infill development is typically executed by converting old buildings and facilities into new uses (redevelopment) or by filling undeveloped space within these areas with environmental review exemptions sometimes acting as incentives. Efficiently facilitated infill and redevelopment is needed to ensure that urban areas remain vital, to respond to changing needs when and where needed, and to help dampen urban sprawl pressures. The principle benefits include: making better use of urban land supplies; increasing access of people to jobs, and jobs to labor force; making better use of existing infrastructure and lowering costs of public services; providing affordable housing; promoting economic development (for example, by relocating office buildings to downtowns); reducing the time, money, energy, and air pollution associated with commuting and other use of SOPs; renewing older neighborhoods and housing stock; and preserving historical landmarks. Case/Example: Boulder (CO), Palm Beach County (FL), and Atlanta (GA). Source/Reference: ARC, C, pp. 10; Nelson and Duncan, 1995, pp. 85-87, pp. 148; US EPA, 2001, pp. 37.