With the long reign of Transurban boss Scott Charlton drawing to an end, investors are mulling over how the board will replace a man who built the toll road group into a “world-class operator”.

From just six tolled roads when Mr Charlton joined Transurban in 2012, the Texan has added 16 more, snapping up some – like Sydney’s Cross City Tunnel – after they went bankrupt while others, like Sydney’s NorthConnex, were built from scratch.