When history leaves a mark: a new measure of Roman roads

This paper introduces a new measure of Roman roads that has been constructed for the Italian territory. The measure computes the length in kilometers of Roman roads at different administrative and territorial levels (NUTS, Local Labor Systems, grid cells), and contributes to the literature on historical infrastructures, providing a new precise measure to use for empirical purposes and easy to extend in all those territories where Roman roads have been constructed. From a mere econometric point of view, the index allows to capture the intensity of the treatment, providing an alternative empirical strategy for all those cases where the simple binary treatment cannot be performed.