s modest, output growth and resource use growth may be substantial indeed. GDP per capita is acknowledged as the main determinant of the demand for land transport, but various measures of road usage are also related to income: estimates of the elasticity of vehicle stock with regard to income vary between 0.75 and 1.25, with the elasticity of vehicle distance driven with respect to income in the 0.2-1.60 range. However, the link between per capita income and the demand for rail transport is not as clear-cut, since the expansion of rail, notably passenger rail infrastructure, is driven more by policy considerations (notably sustainability considerations) than by revealed consumer preferences. GDP growth is also a main driver of the demand for water infrastructure and affects as well the ability of countries - notably developing countries - to carry out the necessary investment. In this regard, Ashley and Cashman note that if developing countries overall grow faster than developed countries over the next three decades, as suggested by World Bank projections, there should on the whole be a proportionately greater ability to pay for water services in the future (a notable exception being sub-Saharan Africa). Also important here is the development of international trade. As Rosengrant et al. (2002) point out, if trade in agricultural products increases in the future, this will be a way for water-poor countries to acquire water-intensive products and specialise in the production of goods requiring limited amounts of water. Finance Given the large amount of resources needed for infrastructure development, financial considerations - including the role to be assigned to public and private investors - play a key role in infrastructure investment. In the case of telecommunications, the substantial funding needed for infrastructure upgrade and expansion will be largely carried out by private actors. Hence, the health of the lending market is essential (Bohlin et al.). IEA also stresses the importance of access to capital for