Roman roads to prosperity: Persistence and non-persistence of public infrastructure

In this paper, we explore the link between public transport infrastructure investments made during antiquity and the presence of infrastructure today; as well as the link between early infrastructure and economic activity, both in the past and in the present. We examine the territory under dominion of the Roman Empire at the zenith of its geographical extension (117 CE), and find a remarkable pattern of persistence showing that greater Roman road density goes along with (a) greater modern road density, (b) greater settlement formation in 500 CE, and (c) greater economic activity in 2010–2020. Exploiting a natural experiment, we find that persistence in road density and the strong link between early road density and contemporary economic development weaken to the point of insignificance in areas where the use of wheeled vehicles was abandoned and caravan trade routes replaced road-based trade from the first millennium CE until the late modern period. Studying channels of persistence, we identify the emergence of market towns during the early medieval period and the modern era as a robust mechanism sustaining the persistent effects of the Roman roads network. Our results contribute to a deeper understanding of the channels through which persistence in comparative development comes about.