5. Future demand for infrastructure will be directly affected by growth in population, broader developments in the local and global economy, technological change, the need for environmental sustainability and consumer preferences.
6. Population growth will drive a significant rise in the demand for infrastructure services. On medium level projections, Australia's population is projected to grow from 22.3 million in 2011 to 30.5 million in 2031 -an increase of 8.2 million or 36.5 per cent.
7. Almost three-quarters of this growth (72.0 per cent) is projected to be in the four largest capitals - Sydney, Melbourne, Brisbane and Perth. In total, these four cities are projected to grow by 5.9 million people, or 46 per cent, to 18.6 million in 2031. This growth will impose additional demands on urban infrastructure already subject to high levels of demand.
8. The other capital cities - Adelaide, Canberra, Hobart and Darwin - are projected to grow in total by slightly more than 0.5 million people or 26.7 per cent. Given this, it is worth considering what steps could be taken to foster greater long-term growth in those cities, which may moderate the consequential infrastructure challenges in the larger cities.
9. The value-add (economy-wide spending) attributable to infrastructure services was estimated to be 13.3 per cent of GDP in 2011. Over 70 per cent of this was attributable to transport. The value-add attributable to infrastructure services is projected to grow roughly proportionate with the economy to 2031.
10. The infrastructure sectors projected to grow faster than GDP are transport, ports, telecommunications, gas pipelines and airports. The sectors projected to grow slower than GDP are water, petroleum, electricity, non-urban roads and non-urban rail.
11. Infrastructure decision making must place a high priority on productivity growth. This can only be achieved through efficient management of existing infrastructure, rigorous and disciplined evaluation of investment initiatives, and efficient delivery of new projects.
12. International and local reviews show that rigorous project selection is key to boosting economic activity and supporting productivity growth. However, investment in poorly conceived projects can undermine a country's economic prospects.