The development of transport infrastructure is a central issue for states, which spend billions to connect cities. But what is their real effect on the municipalities concerned? Researchers have looked at the evolution of the income composition of the population of cities in Switzerland once they are connected to the motorway network. By analyzing data from 1950 to 2010, they found that this new accessibility leads to substantial benefits for wealthy people, but indirect costs fall disproportionately on people with low incomes.