Editing Sector model (section)

==Limitations ==
The theory is based on early twentieth-century rail transport and does not make allowances for private cars that enable [[commuting]] from cheaper land outside city boundaries.<ref name="Rodwin">Rodwin, L. (1950) "The Theory of Residential Growth and Structure", ''Appraisal Journal'', 18, pp.295-317</ref>  This occurred in [[Calgary]] in the 1930s when many near-[[slums]] were established outside the city but close to the termini of the [[tram|street car]] lines.  These are now incorporated into the city boundary but are pockets of low-cost housing in medium cost areas.<ref name="Smith"/> The theory also does not take into account the new concepts of edge cities and boomburbs, which began to emerge in the 1980s, after the creation of the model. Since its creation, the traditional Central Business District has diminished in importance as many retail and office buildings have moved into the suburbs.
*Physical features - physical features may restrict or direct growth along certain wedges
*The growth of a sector can be limited by [[exurb|leapfrog]] land.
*The theory too lacks the idea based on land topography.