nly split across regions between OECD-industrialised, Big 5 and developing countries, with relatively little coming from non-OECD-industrialised countries. The future consequence of rebuilding depreciated existing assets is not reflected in the base year new construction figure - indicating that most governments are still engaged in practices ingrained during the 1980-90s when capital expenditures and maintenance budgets were generally squeezed very hard to deal with public debt/deficit challenges. To put these forecasts of road new construction into perspective, it is worth remembering that the postwar construction of industrialised country road networks largely occurred over a 40-year period from 1945-85, SO that the 30-year time period considered here may witness comparable road network construction in some of the rapidly growing and more prosperous Big 5 and developing countries of the world (e.g. China). INFRASTRUCTURE TO 2030: TELECOM, LAND TRANSPORT, WATER AND ELECTRICITY - ISBN 92-64-02398-4 - © OECD 2006 4. KEY FACTORS DRIVING THE FUTURE DEMAND FOR SURFACE TRANSPORT INFRASTRUCTURE There is some risk that the future new construction requirements in Table 4.5 may be too high. Certainly there has been no conscious effort to force "sustainability" and climate change (e.g. greenhouse gas, GHG) targets onto the road sector, although there has been some attempt to place upper-bound limits on road capital asset-to-GDP ratios. As GDPpc grows across the "threshold" value of USD 5 5000 per capita in many countries (e.g. China) there will be enormous social/consumer pressures for vehicle ownership and road infrastructure responses, which will be extremely difficult to dampen. A substantial amount of the initial "upward drift" in the new construction (as a percentage of GDP) results from the model assumption that countries will seek to "converge" toward industrialised ratios of road capital stock-to-GDP - even as these decline among industrialised countries. It may well be that the fiscal challenge to finance this ra