The land-use decisions of cities and towns also explain some of the regional differences in energy use. Townhouses are more energy efficient than single-family homes because less heat, for example, is used per person. Similarly, areas with more homes in a compact neighborhood encourage walking, biking and transit, thereby reducing transportation energy use. A 2011 US EPA study found that multi-family homes in urban neighborhoods, with well-insulated buildings and fuel-efficient cars, use less than two-thirds of the energy used by conventionally built single-family houses in suburban areas (with standard cars).