Traffic congestion drives urban evolution Available to Purchase

As a city grows, it evolves from a so-called monocentric organization, with activities concentrated in the same geographical area—typically a central business district—to a polycentric organization, in which a number of subcenters coexist. Researchers Rémi Louf and Marc Barthelemy, both at France’s Atomic Energy Commission in Saclay, have now developed a stochastic model that accounts for the emergence of that transition as an effect of rising traffic congestion. According to a 30-year-old economic model, the location at which individuals choose to work is one that maximizes income, taken as the difference between their wages and commuting costs. But cities are not static distributions of households and businesses; as populations increase, so do congestion and the time and thus cost of a commute. That trend, incorporated into the researchers’ new model, reduces the attractiveness of some areas in which individuals might otherwise opt to work and raises the attractiveness of others,...