Modification of the Law of Retail Gravitation
There are some modifying factors in the Law of Retail Gravitation. For example, one town may have more energetic and intelligent retailers than a competing town ; Or the population of one town may increase faster than the stocks in its retail stores. Such a town may not draw as much trade as is predicted by the formula. An industrial town may grow up and become larger than an older and established trading-centre town.
It may take the newer town a long time to gain retail ascendancy over the older established town where the people are accustomed to shop. This seems to be the case with many industrial towns within larger metropolitan areas.
Mr. W. J. Reilly in formulating the law recognised 11 factors that might modify the trade area of a trading centre. These are—
(1) Transportation facilities by rail, bus and air as well as express and parcel post rates ;
(2) Lines of communication such as newspaper, circulation, radio station and TV coverage, telephone rates ;
(3) Type of territory around the centre ;
(4) Density of population ;
(5) Proximity of other large cities :
(6) Business attraction of a centre aside from the stocks of goods in its stores, as banking facilities, services rendered by stores ;
(7) Parking facilities :
(8) Social and amusement attractions ;
(9) Competition from smaller cities ;
(10) Topographical and climatic conditions and
(11) Leadership of business in the city.
In view of all the factors that can modify trade movement, it is surprising that the mathematical formula predict trade movements with a high degree of accuracy.