Ferdinand Rauch

Resetting the Urban Network: 117-2012

Do locational fundamentals such as coastlines and rivers determine town locations, or can historical events trap towns in unfavorable locations for centuries? We examine the effects on town locations of the collapse of the Western Roman Empire, which temporarily ended urbanization in Britain, but not in France. As urbanization recovered, medieval towns were more often found in Roman-era town locations in France than in Britain, and this difference persists today. The resetting of Britains urban network gave it better access to natural navigable waterways when this was important, while many French towns remained without such access. We show that towns without coastal access grew more slowly in both Britain and France from 1200-1800, and calculate that with better coastal access, Frances urban network would have been up to 20-30 percent larger in 1800.

The Benefits of Forced Experimentation: Striking Evidence from the London Underground Network

We estimate that a significant fraction of commuters on the London underground do not travel their optimal route. consequently, a tube strike (which forced many commuters to experiment with new routes) taught commuters about the existence of superior journeys, bringing about lasting changes in behavior. This effect is stronger for commuters who live in areas where the tube map is more distorted, thereby pointing towards the importance of informational imperfections. We argue that the information produced by the strike improved network-efficiency. Search costs are unlikely to explain the suboptimal behavior. Instead, individuals seem to under-experiment in normal times, as a result of which constraints can be welfare-improving.

The Geometry of the Distance Coefficient in Gravity Equations in International Trade

Gravity equations in trade imply that trade flows are proportional to the size of a country and inversely proportional to distance. This paper develops the analogy of gravity in physics with gravity in trade and provides geometric intuition for a large class of mathematical processes in two‐dimensional space for which these relationships would be expected. This model implies that distances between countries in empirical gravity estimations should be measured as weighted harmonic means of pairwise distances of local economic activity.