As an urban area increases in population, it expands territorially at the margin, and this expansion invariably requires sales of land by previous owners and purchases of land by new owners. Thus a market for suburban land is necessarily created. This market has many peculiarities, and the following pages will deal with some of them. The thesis here is that the form of the market in itself has a considerable effect on the kind of land use and the type of suburb which is developed. The chapter will therefore attempt to measure how far and in what ways the nature of the market determines or affects the kind of suburbs which emerge, and how far and in what ways the market might yield to public efforts to change the outcome.
The economic concept of demand concerns the relation between the quantity of any good or service purchased or consumed and its price or some other variable. An important part of this basic concept is the idea of elasticity, or the relative change in quantity associated with a relative change in price or other variable. When changes in quantity are relatively great in response to a small change in price and total expenditures increase as price falls, the demand is said to be relatively elastic.
The economic concept of demand was originally applied to price-quantity relationships. In its simplest or purest form, a demand schedule or relationship assumes that all factors other than price and quantity remain unchanged. If this latter condition is met, the quantity purchased or consumed increases as price falls, without -- as far as we know -- any exception. Hicks has distinguished between the substitution and the income effects of price changes.1 If the price for commodity A falls, then some or all consumers will buy more of it and less of commodity B, to the extent that these two commodities are in any way substitutes for one another. At the same time, the reduction in price of commodity A increases the real income of the consumer; he has to spend less money to buy the old volume of that commodity, while leaving unchanged his volume of purchases of all other commodities.
The income effect of a price change may under some circumstances have effects different from the price-substitution effects. If income increases significantly because____________________