This Round Table is one of a series of research events to discuss tools to improve transport planning. It addressed the macroeconomic effects of transport infrastructure policies, and aimed at identifying analytical and empirical tools that could determine the overall volume of public expenditure for transport infrastructure investment. It also sought to identify state-of-the-art methods for assessing the macroeconomic impact of transport infrastructure investment.  Background papers were provided by David Canning (Harvard University), Charles Hulten (University of Maryland) and Andreas Kopp (OECD/ECMT Transport Research Centre).