The diagrams illustrate two underground road tunnels in different Australian cities, highlighting their construction periods, costs, dimensions, and lane capacities.
Overall, Tunnel A was built earlier and is smaller in scale, serving as a connection between two parts of the city divided by a river. In contrast, Tunnel B, constructed later, is larger, more expensive, and runs beneath a canal or a major tunnel, parallel to the city’s main surface road.
Tunnel A was constructed between 1987 and 1992, with a total cost of approximately 556 million US dollars. It spans 2.2 kilometers in length and has a height of 25 meters. Located beneath a river, it is reinforced with stone and sand and accommodates two lanes in each direction.
By comparison, Tunnel B, built from 2004 to 2007, had a significantly higher construction cost of 1.1 billion US dollars—double that of Tunnel A. It is also larger, measuring 3.6 kilometers in length and 35 meters in height. Unlike Tunnel A, it runs beneath a canal or a major tunnel and supports a higher traffic capacity with three lanes in each direction.
In summary, while both tunnels serve as crucial transport routes, Tunnel B is more modern, larger, and costlier, with greater traffic capacity compared to Tunnel A.