But it is still cheaper to not tunnel and instead buy the land and bulldoze the properties. We only need 2 super short tunnels to save heritage buildings.fishinajar wrote: Good insight claybro. 1.5km could get under Henley Beach and Sir Don. That would be a good outcome.
Where would the vents go?
The surface South Road does not benefit from reduced drives way and right hand turns etc.
It even creates work with people moving and building new properties.
There is 3.2km of road between T2t to James Congdon Drive with about 70 residential style properties(many with businesses in them) each worth about $450,000-600,000 and 20 larger businesses properties.
Lets say you can buy the residential properties for $40million, but lets round up to $100million just because. That gives each property over $1million!
Then buy the larger properties for $200million(that is $10mil to each business!), giving a total of $300million.
I am fairly confident all this land can be gotten for far far far less than the above.
$300million and you have all the land you need for 3km or you could build a tunnel for $300-500million per km.
Also everyone forgets about upkeep of bridges and tunnels. They are not one off costs.
The ongoing upkeep of a trench will be significantly less than a tunnel.