The diagram illustrates the specifications and construction details of two road tunnels, namely Tunnel A and Tunnel B, situated in an Australian city.
Overall, the two tunnels differ significantly in construction period, cost, dimensions, and structural components.
Tunnel A was constructed over a span of five years, from 1987 to 1992, with a total expenditure of $556 million. This tunnel features a twin tube cross-section and has a length of 2.2 kilometres. Additionally, it possesses a height of 25 metres and is primarily constructed from steel and sand, which might suggest a focus on durability and resistance to environmental pressures during that era.
In contrast, Tunnel B was built more recently, from 2004 to 2007, at a significantly higher cost of $1.1 billion. This tunnel also has a twin tube cross-section, but it has a larger span of 3.6 kilometres, and height of 35 metres which is greater than tunnel A. The increased investment and modern design of tunnel B may indicate advancements in engineering techniques and material used.