Recently at the Warren Centre (http://thewarrencentre.org.au/ip30-panel-investigates-the-infrastructure-governance-opportunity/) there was some commentary around the cost of duplicating Brisbane’s Gateway Motorway Bridge. Namely, between the original and the duplicate, costs increased fivefold. On the surface that would be a stunning thing. However, when we consider 24 intervening years (1986-2010) between the costings for the two projects, we are looking at an annualised increase in costs of 6.9%. This is still significant when inflation only increased 3.4%p.a. over the same period. I know there are construction price indices around as well. However, I wonder whether design and materials were significantly different, and the connecting road infrastructure was more challenging. That might explain some of the residual increase. Also, the duplicate would have been constructed in a much tighter market for engineering and construction services. Should we have bought the extra lanes way back in 1986 or would the opportunity cost have been too large?