Bid-Rent Analysis

Bid-rent analysis is Alonso's transplantation of von Thünen's 1826 agricultural land-rent logic into the city. Von Thünen showed that crops sort into concentric rings around a market according to the rent each can pay at a given distance; Alonso replaced crops with urban land uses and the agricultural market with the central business district, so commerce, then residence by income, sort into urban rings. Both derive the observed rent as the upper envelope of competing bid-rent curves, with the steepest bidder winning the most central land.

Because central location confers accessibility — to customers for firms, to jobs and services for households — and that accessibility is valuable. A firm or household located farther from the centre incurs higher transport or commuting costs, leaving less money available to pay for land while still reaching its target profit or utility. To remain equally well off, the rent it can bid must fall as distance rises, which is exactly the downward slope of the bid-rent curve; the rate of fall depends on how transport-sensitive the activity is.

In the basic Alonso model households sort by their relative valuation of space versus accessibility. Wealthier households often value space (larger lots) more and can absorb commuting costs, giving them flatter bid-rent curves that win the more distant, cheaper land, while lower-income households outbid them for cramped but central locations. The exact pattern depends on income elasticities and on amenities, which is why real cities show both wealthy suburbs and wealthy gentrified cores — outcomes later models add to the bid-rent core.