Barrier Function of the Urban Environment and Its Quantitative Assessment (a Case Study of Moscow)

— The article analyzes intracity borders–barriers in Moscow. The author calls the barrier between urban nodal areas with a high degree of barrier function a barrier in an urban environment. Such a boundary—rigid, distinct, quasilinear—has existed for a long time (decades or more). The barrier function of the urban environment in the author’s terminology is the degree of disintegration of a city into relatively loosely connected areas with internal integrity. Three types of urban barriers are distinguished in terms of genesis: automobile, railway, and water. Military, forest, industrial, and fenced private areas (condominiums and individual land plots) are beyond the scope of the study. The barriers created by them do not separate social, economic, political, and other areas of cities, but specific territories from the rest of the urban environment (i.e., they are independent regions). For each city, there are barriers with maximum and minimum border permeability. In this case, the permeability of intracity borders is understood as the possibility of intersection and the degree of intersection of the barrier. It is proposed to call an urban barrier with maximum permeability “permissive barrier.” An urban barrier with minimum permeability can be called a “filter barrier.” Comparison of the “permissive barrier” and the “filter barrier” makes it possible to assess the range of territorial differences within the city. Comparison of different types of barriers with permissive and filter barriers makes it possible to estimate the characteristic permeability of the barriers against the maximum and minimum values.