The construction of freeway tunnels is far more challenging and expensive in Melbourne due to difficult geological conditions.
The price tag for Transurban's massive freeway tunnel in western Melbourne will be twice that for a project of similar dimensions being undertaken by the same company in Sydney.
The six-lane Western Distributor toll road will consist of a tunnel and elevated freeway passing through the west Melbourne suburb of Footscray, serving to connect the West Gate Freeway to CityLink.
Transurban and Victorian Premier Daniel Andrews revealed plans for the freeway tunnel to the public in April, just a month after the toll road builder approached the government with the project as part of its “market-led proposals” program.
Observers have since made much of the exorbitant cost of the Western Distributor as compared to the similar NorthConnex tunnel project in Sydney.
The NorthConnex project will connect the M1 Pacific Motorway to the M2 Hills Motorway, running through the suburbs of Normanhurst, Thornleigh and Pennant Hills.
While the Western Distributor will eventually shape up to be the larger of the two projects by 3 kilometres, with a total length of 12 kilometres as compared to 9 kilometres for NorthConnex, it will cost more than twice the amount to build.
NorthConnex, work on which commenced earlier this year, will cost $2.65 billion to bring to Sydney, while the price tag for the Western Distributor is currently pegged at $5.5 billion.
Transurban has imputed the reduced cost for NorthConnex to preferable geological conditions in Sydney that are ideal for tunnelling through the earth.
A Transurban spokesperson pointed out that much of the land beneath Sydney consists of Silurian sandstone, which is soft and comparatively easy to bore thorough, while Melbourne’s challenging geological conditions will require the use of more complex tunnelling methods.
In addition to its increased cost, obtaining sufficient funds for the Western Distributor may also prove more difficult.
Transurban, the NSW government and the federal government are jointly funding the construction of NorthConnex. For the Western Distibutor, however, Transurban plans to derive two thirds of funds from road tolls on both CityLink and the new freeway, with Canberra accounting for the final third.
Prime Minister Tony Abbot has indicated, however, that the federal government will not pony up money for the proposal unless the Victorian government does so as well.
Some experts are also questioning whether the huge infrastructure project should receive any government funding at all. Jago Dodson, director of RMIT’s Centre for Urban Research, points out that Transurban is a private concern that should bear all the risk of its own toll road undertakings.
Other transportation specialists, such as Chris Standen from the University of Sydney's Institute of Transport and Logistics Studies, consider the construction of massive freeways to be an untenable solution to today's urban transportation challenges. Standen contends that huge freeways fail to solve congestion problems in the long-run, as they simply bring more vehicles onto roads.