Roderick.

With the world in bridgephobia, hasty preventative measures are being put in place to avoid a repetition of the Baltimore disaster.  Large ships must now have tug assistance to pass under ,may bridges (eg Sydney Harbour, Brisbane Gateway); emergency traffic signals are being installed.
Tasmania has already banned the Antarctica supply boat Nuyina from passing under Tasman Bridge: it has to go to Burnie to bunker.  That followed the collapse of the first Tasman Bridge, and a more-recent sinking of two tugs by an out-of-control cargo ship.
Perth and Adelaide are safe: lack of depth prevents large vessels from reaching their railway bridges.
Victoria had encased bridge supports in concrete after the Granville disaster.  It has now reduced speed limits over the Spencer St spans of Flinders St Viaduct (even lower than the existing low limit) and over Napier St, Footscray.  Testing has revealed a design defect in all spans of the first elevated project: Caulfield - Dandenong.   Pending the design of suitable rectification, a speed limit has been imposed over all spans which cross roads.  A spokesperson stated: 'This will have timetable implications, but customer safety is our number one priority.  We thank you for your patience and understanding'.