In 1932, the average annual daily traffic was around 11,000 and now it is around 160,000 vehicles per day.

The Sydney Harbour Tunnel was built to cope with ever increasing harbour traffic problems and opened in August 1992 . It is 2.3 kilometres long and cost A$554 million to construct. It is strong enough to withstand the impact of eathquakes and sinking ships. It carries around 75,000 vehicles a day.