Mixed-use development (or mixed land uses) can occur on a number of levels. On a site-specific basis, individual buildings or complexes can be designed to incorporate a variety of uses. At the neighborhood level, mixed-use development refers to the arrangement of different uses across several blocks or acres of land so that they are not physically isolated from one another. At the subregional level, mixed-use often aims to balance jobs and housing so that people have the opportunities to live closer to their places of employment. Mixed-use zoning represents flexible zoning that allows various types of land uses to be combined with a single district. Land use mixing may influence travel demand in a number of ways, but its greatest impact is thought to be on mode choice (Cervero, 1996a, pp. 363). At sites with TDM incentives, areas with a substantially mixed land use had more than double the transit more share of other site, that is, 6.4% share in centers with a substantial mix compared with 2.9% in those with a limited mix (US DOT, 1994). Controlling for other land use and household factors, a doubling in accessibility results in a 7.5% decrease in the number of vehicles owned (Kockelman, 1997). Source/Reference: US EPA, 2001, pp. 59-65; Smart Growth Network, 2000, pp. 43