A theory explaining how the attributes of cities scale with city size may help to inform urban planning. [Also see Report by Bettencourt] As cities get bigger, they generate economies and diseconomies of scale, referred to by Marshall more than a century ago as the effects of agglomeration (1). Simple theories assume that cities exist due to a trade-off between these positive and negative forces of agglomeration and that the benefits continue to outweigh the costs of cities as they grow ever larger (2). But precisely what happens as cities grow? On page 1438 of this issue, Bettencourt (3) shows that the ways in which people interact with one another in cities lead to power laws—or allometric laws—that relate population, area, and attributes of the population to scale.
[1]
J. S. Andrade,et al.
Modeling urban growth patterns with correlated percolation
,
1998,
cond-mat/9809431.
[2]
L. Bettencourt,et al.
Supplementary Materials for The Origins of Scaling in Cities
,
2013
.
[3]
M. Batty.
When all the world's a city
,
2011
.
[4]
J. Ashby.
References and Notes
,
1999
.
[5]
D. Helbing,et al.
Growth, innovation, scaling, and the pace of life in cities
,
2007,
Proceedings of the National Academy of Sciences.
[6]
James Clerk Maxwell,et al.
The Scientific Letters and Papers of James Clerk Maxwell: Volume 1, 1846-1862
,
1990
.