The provided maps show the difference of underground tunnel system for vehicles between two different Australian regions.
Overall, in the first city the underground tunnel built earlier than the second city but cost a lot cheaper compared to the second city. The first city tunnels are smaller and designed only with two tunnel that can hold two cars on each tunnel, whereas in second city tunnels are larger that can hold more cars. Additionally, they have differences in their construction and length.
In the first city, the underground tunnel system had been built under the bridge that connected between two areas. Built in 1986-1998 that cost approximately $555 million with two tunnel that can take up to two cars on each tunnel. This tunnel has been built 1,5 meters under the sea-level surrounded by sand and have length of 2,2 kilometers.
On the other hand, the second city built their underground tunnel under the highway in central city. Built in 2002-2006 that cost around $1,1 billion with two tunnel that can take up to three vehicles on each tunnel. The tunnel built 2,5 meters under the sea-level surrounded by stone and clay and have length of 3,6 kilometers.
