 growth (and better-quality roads), and as freight distances grow with industrialisation, specialisation and intensive trade/supply chain complexity. 3. Impact of key drivers on future surface transport demand As discussed in the previous section, there are clear upside and downside risks (or pressures) that would influence the road and rail capital stock and new construction forecasts to 2030. This section addresses the following factors: Modal split and shift from road to rail. Freight US. passenger transport growth. Information and communications technologies (ICT). Road capacity utilisation. Road pricing. Spatial distribution/population density. Security and climate change risk. Country-specific and regional variation. Demographic factors. Public capital constraint as a limit on surface transport. Modal split - shift from road to rail A natural "policy experiment" was undertaken during the 1980-90s to put the macroeconomy and public finance on a more stable and growth-oriented basis. This policy experiment involved significant curtailing of public capital spending in many areas - particularly in transportation. The subsequent slowdown in productivity growth, rising work-time pressures and growing road congestion suggest that the "do-nothing" approach to effect modal shift from road to rail - by hoping that enough road congestion will force commuters/ passengers to rail - does not work in the absence of improvements to rail (and public transit) infrastructure. 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 While public investment in road infrastructure was curtailed in most countries (the United States being a possible exception), private investment in road vehicle ownership and spending to sustain road use grew. This was despite growing awareness of environmental and sustainability concerns and problems from growing automobile dependence and use. In order to fundamentally al