Roads are the arteries through which the economy pulses. They connect sellers to markets, workers to jobs, students to education, and the sick to hospitals. Yet much of the developing world, Africa in particular, lacks adequate transportation infrastructure. Accordingly investments in transportation remain a cornerstone of the development agenda. Sub-Saharan Africa spends roughly $6.8 billion per year on paving roads, and the World Bank invests more on roads than on education, health, and social services combined. Despite the development focus on transportation, methodologies for evaluating...