One of the great puzzles of Sub-Saharan African economic history is that wheeled transportation was barely used prior to the colonial period. Instead, head porterage was the main method of transportation. The consensus among historians is that this was a rational adaption to the underlying...

Understanding the sensitivity of gasoline demand to changes in prices and income has important implications for policies related to climate change, optimal taxation and national security, to name only a few. While the short-run price and income elasticities of gasoline demand in the United...

Measurement of seat belt and air bag effectiveness is complicated by the fact that systematic data are collected only for crashes in which a fatality occurs. These data suffer from sample selection since seat belt and air bag usage influences survival rates which in turn determine whether a...

Specialization alters the incidence of manufacturing trade costs to buyers and sellers, with pro-and anti-globalizing effects on 76 countries from 1990-2002. The structural gravity model yields measures of Constructed Home Bias (the ratio of predicted local trade to predicted frictionless local...

This paper surveys the theoretical and empirical literature on the relationship between the spatial distribution of economic activity and transportation costs. We develop a multi-region model of economic geography that we use to understand the general equilibrium implications of transportation...

The importance of increments to an existing highway system depends upon their contributions to the accessibility provided by the existing network. Nearly 40 years ago, Mohring [1965] suggested this logic for planning optimal highway investment programs. He argued it could be implemented by...