transport infrastructure needs have been estimated at
$11 trillion over the 2009–2030 period (OECD, 2011).
To close the gap on the large infrastructure deficit in
developing countries, including in transportation,
existing estimates indicate that spending must reach
$1.8 trillion–$2.3 trillion per year by 2020 compared
with the current levels of $0.8 trillion–$0.9 trillion a year
(United Nations Development Programme, 2013)