Chapter 15: Transportation and Urban Compactness

Cities vary in their degree of compactness, usually measured in terms of population densities (although the radius of the urbanized area might be a useful alternative measure). Other somewhat more complex possibilities include the concept of median radial distance (Prud’homme and Nicot, 2003), which measures the distance beyond which one-half of the metropolitan population lives, and the index of compactness (Bertaud and Malpezzi, 1998), which measures the deviation in the actual spatial distribution of the population from a cylinder where the height of the cylinder is proportional to the assumed uniform population density of the metropolitan area. Compactness is measured by the extent to which the integration of the actual population density approximates the volume of the cylinder.