The plans illustrate details about two road tunnels, namely Tunnel A and Tunnel B, in an Australian city. Overall, there are noticeable differences between the two tunnels in terms of depth, length, construction cost, and duration.
Tunnel A was built earlier, between 1987 and 1992, with an estimated construction cost of $556 million. In terms of dimensions, it has a depth of 25 meters and a length of 2.2 kilometers. The underwater tunnel is secured by stone and sand from above. Each of the twin tubes accommodates two lanes of traffic.
By comparison, Tunnel B is relatively new, developed between 2004 and 2007, at a total cost of $1.1 billion, roughly double that of Tunnel A. Additionally, it is a larger-scale project, with a depth of 35 meters and a length of 3.6 kilometers. The tunnel is built below a highway and is wide enough for three lanes of traffic.