The diagrams offer valuable insights into two road tunnels in Australian cities, detailing their design, the time taken to build them, and their respective costs.
The first tunnel, completed between 1986 and 1998, cost $555 million to construct. It has a relatively low clearance of 1.5 meters, suggesting it’s suitable for smaller vehicles. Its illustration, with stands, indicates a bridge-like structure supporting the tunnel, a design that often I used as a city’s iconic landmark.
On the other hand, the second tunnel, constructed more recently between 2002 and 2006, required a bigger investment of $1.1 billion. This tunnel offers a greater height clearance of 2.5 meters, accommodating larger vehicles. It spans 3.6 kilometers and is depicted as being reinforced with stone and clay, hinting at a substantial underground passageway cutting directly beneath a city.
Comparatively, the second tunnel is longer and costlier and features a larger clearance height, reflecting advancements in construction and perhaps increased functional demands.