The economic arteries and veins. Roads, ports, railways, airports, power lines, pipes and wires that enable people, goods, commodities, water, energy and information to move about efficiently. Increasingly, infrastructure is regarded as a crucial source of economic competitiveness. Investment in infrastructure can yield unusually high returns because it increases people’s choices: of where to live and work, what to consume, what sort of economic activities to carry out, and of other people to communicate with. Some parts of a country’s infrastructure may be a natural monopoly, such as water pipes. Others, such as traffic lights, may be public goods. Some may have a network effect, such as telephone cables. Each of these factors has encouraged government provision of infra¬structure, often with the familiar downsides of state intervention: bad planning, inefficient delivery and corruption.