Like other government spending, infrastructure investment boosts aggregate demand, potentially sparking broader-based output growth through scale economies which feed into productivity increases. This typically leads to greater private sector investment, and by extension, also raises private demand for physical capital over a longer time-horizon (Dissou and Didic, 2013). These complementary effects on private capital formation tend to be cumulative, as infrastructure provision affords greater certainty for private industry, and the consequent increased rates of capital formation help to crowd in investments in other sectors of the economy.4 In turn, increased productivity and rising incomes lead to higher demand for various infrastructure services.