Empirical evidence has been shown that some urban variables scale non-linearly with the city population size.
More specifically, some socio-economic variables, such as the number of patents, wages and GDP, show a super-linear behaviour with the population of the city. On the other hand, infrastructure variables, such as the number of gas stations and length of streets, scale sub-linearly with the city population, generating a scale economy.
However, does this scaling properties observed in a system of cities (transversal scaling) also work for individual cities in different stages of their growth process (longitudinal scaling)?
The answer to this question has important policy implications,
but the lack of suitable data has so far hindered rigorous empirical tests.
The work that will be presented was developed looking at the evolution of two urban variables, GDP and water network length, for over 5500 cities in Brazil.
It will be shown that longitudinal scaling exponents are city-specific, however they are distributed around an average value that approaches the transversal scaling exponent provided that the data is decomposed to eliminate external factors, and only for cities with a sufficiently high growth rate.
This result adds complexity to the idea that the longitudinal dynamics is a micro-scaling version of the transversal dynamics of the entire urban system.
1) Ribeiro, F. L., Meirelles, J., Netto, V. M., Neto, C. R. & Baronchelli, A. On the relation between Transversal and Longitudinal Scaling in Cities. PLoS One 1–20 (2020). doi:10.1371/journal.pone.0233003
2) Ribeiro, F. L., Joao Meirelles, Ferreira, F. F. & Neto, C. R. A model of urban scaling laws based on distance-dependent interactions. R. Soc. Open Sci. 4, (2017).
3) Meirelles, J., Neto, C. R., Ferreira, F. F., Ribeiro, F. L. & Binder, C. R. Evolution of urban scaling: evidence from Brazil. PLoS One 10, 1–15 (2018).