government policies to curb demand growth and promote switching to cleaner fuels (including more use of renewables and distributed energy), world electricity demand and investment needs grow less rapidly in almost every region, on average 15% less over the 25-year period. The main uncertainties surrounding the adequacy of electricity investment worldwide relate to the impact of market reforms, environmental constraints and access to capital. In general, the effects of market reforms and environmental constraints are most uncertain in OECD countries. Policy makers are seeking to address concerns about the adequacy and timeliness of investments to ensure system reliability and an adequate quality of service by establishing a market framework that sends efficient market signals to investors. Land transport Two modes of surface transport are addressed, road and rail. Road transport: The report estimates new infrastructure construction (i.e. net additions and maintenance/replacement) over the period 2000 to 2030 at between USD 220 billion and USD 290 billion per year. The largest component of the road infrastructure requirement arises from the need to maintain, upgrade and replace existing road assets, which deteriorate over time. A smaller component actually goes to augment the road capital asset value. These estimates are broadly in line with previous albeit shorter-term projections (e.g. World Bank). Roughly two-thirds of all new infrastructure construction is expected to take place in OECD countries, and about one-fifth in the Big 5 economies. Rail transport: Infrastructure requirements (new construction) of between USD 50 billion and USD 60 billion per year are projected over the period 2005-30. These are substantially higher than previous studies suggested, in part because they reflect some significant rail upgrading plans envisioned and commenced under the EU TEN-T programme and major rail-building plans (including high-speed rail) in China and other Big 5 economies. Again, some two-thirds of the rail infrastru