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Don't forget that the cost is actually $2.2b, and that there are 8 lanes of traffic, and includes the double track rail component.

Is there any good reason why we couldn't save money by initially just building one half of it?
By that I mean 4 lanes (divided into 2+2 with full height wire fences), bridges long enough for the full eventual width of the road and railway, but no interchanges other than the end ones.

Wasn't that what somebody said about the Southern Expressway? Couldn't we save money initially by building just half of it?

rhino wrote:Wasn't that what somebody said about the Southern Expressway? Couldn't we save money initially by building just half of it?

When I wrote what I did I regarded that comparison as obvious, hence I clarified exactly what I meant. Obviously we don't want half a freeway again, but the Northern Connector is so overspecced that we could make do with half of it reconfigured as a full freeway.

And the main problem with the Southern Expressway was that it wasn't really regarded as an initial half - no provision was made for the alignment of the other carriageway.

Actually, the Southern Expressway as it is - is actually the southbound portal of the "freeway". The northbound portal is the part to be duplicated.

I think you mean "carriageway" - a portal is an entrance

Really? Guess you learn something new everyday then. I could have sworn I've heard portal used in the sense I used it in before, though?

Lets please not get into a disscussion about doing a typical Adelaide half job..... How about we do the Northern Connector properly from the start. We DO NOT want another Southern Expressway scenario for Adelaide.

Unfortunately, as much as I would love to see it build according to the artists impressions, I can't see it getting done properly from the start. The government has a track record of cost blowouts - $1billion is already ridiculously high, but I wouldn't be surprised to see it hit $2billion in its current configuration (i.e. 4x4 lanes plus dual track rail in the median). That kind of money could transform South Road in one hit! One has to ask, which project is more important?

When the state and federal governments start their dealings in terms of funding share, compromises will almost certainly be made. We're likely to be looking at 2x2 lanes with single track rail in the median (no, I'm not being a pessimist, I'm just thinking about what will happen given that we have for decades had governments who like to do things half-arsed).

The Northern Expressway comes to mind - this was originally planned as 3x3 lanes, costing ~ $300 million. What happened? Now 2x2 lanes, and a MASSIVE cost blowout of 80%!

The expensive cost of the Northern Connector is largely attributed to the fact that it requires a lot of property acquisition.

The section of South Road between the PR Expressway and GJ Road is already looking to cost at least $750m, just for a meagre 3km or so section of road. South Road from the Southern Expressway to the PR Expressway is 22km - quick math - that's $5.5b to do the entire South Road, more really because propety is more expensive and subdivided into smaller allotments within the inner-city.

Northern Expressway was always planned to have 3x3 lanes. This was factored in from the start. They've built it 2x2 to accomodate the demand it requires upon its opening, and have the land provision for third lanes when the demand rises. This provision significantly reduces construction costs in future when its needed.

Aidan wrote:Is there any good reason why we couldn't save money by initially just building one half of it?
By that I mean 4 lanes (divided into 2+2 with full height wire fences), bridges long enough for the full eventual width of the road and railway, but no interchanges other than the end ones.

While a smaller scale project, something similar to this was going to be done with Mandurah Enterance Road in Perth but last week it was announced that the extra $25m would be funded to build road carriageways both sides of the Perth/Mandurah railway line.

http://www.sgalliance.com.au/mer/pdf/MER_overview.pdf

With regard to the Northern Connector a single carriageway of 4 lanes divided into 2 lanes each way would have the following problems,

1) No central median.
2) No (or limited) emergency stopping lanes.

A speed limit significantly lower than 110km/hr would then be required for safety reasons which would limit it's effectiveness as an alternative to Port Wakefield Road.

The above problems could be overcome by a wider carriageway than 4 lanes but this would introduce redundancy when the second 4-lane carriageway was built and there's also the question of what width of carriageways the bridge structure currently under construction at the northern end (Port wakefield Road) can accomodate.

Shuz wrote:Northern Expressway was always planned to have 3x3 lanes. This was factored in from the start. They've built it 2x2 to accomodate the demand it requires upon its opening, and have the land provision for third lanes when the demand rises. This provision significantly reduces construction costs in future when its needed.

This is what is done in Perth with the Kwinana/Mitchell freeway and the outer suburban highways such as Roe/Tonkin/Reid.

Some bridges (Roe Highway inparticular) do have 4 lanes on the one structure with a large concrete barrier down the middle to keep the opposing traffic flows apart. The length of these sections though are short. These bridges will ultimately be duplicated as part of the final 3-lanes each way freeway design.

Paulns wrote:Lets please not get into a disscussion about doing a typical Adelaide half job..... How about we do the Northern Connector properly from the start. We DO NOT want another Southern Expressway scenario for Adelaide.

Nobody is suggesting another Southern Expressway scenario. But it will be a long time before we need 4 lanes in each direction.

$2.2bn is an awful lot of money, and spending it all on the Northern Connector would prevent it being spent on more worthwhile projects. If we can find a way of cutting the initial cost while not compromising the eventual usefulness, we should.

We do need the road to go both ways.
We do need it to go all the way from South Road to the Northern Expressway.
And where roads go over it, they do need to span the full width.

However we won't need interchanges - vehicles that aren't going all the way can use the Port River Expressway and Port Wakefield Road instead.

There's nothing new about converting a road from 2+2 to 4+4+2(rail). Perth's done something similar. So has England (when the A2 / M2 was upgraded and a new high speed rail line constructed beside it).

We must plan for the future - but that doesn't mean we should build it all in one go.

Shuz wrote:The expensive cost of the Northern Connector is largely attributed to the fact that it requires a lot of property acquisition.

Does it really? I thought it was mostly saltpans that are being abandoned anyway!

The section of South Road between the PR Expressway and GJ Road is already looking to cost at least $750m, just for a meagre 3km or so section of road. South Road from the Southern Expressway to the PR Expressway is 22km - quick math - that's $5.5b to do the entire South Road, more really because propety is more expensive and subdivided into smaller allotments within the inner-city.

Where did you get the $750m figure from? That's a quarter of a million dollars per metre! How much are they planning to widen the road?

Northern Expressway was always planned to have 3x3 lanes. This was factored in from the start. They've built it 2x2 to accomodate the demand it requires upon its opening, and have the land provision for third lanes when the demand rises. This provision significantly reduces construction costs in future when its needed.

What was the third set of 3 lanes planned to be for? Or do you mean 3+3 lanes?

drsmith wrote:With regard to the Northern Connector a single carriageway of 4 lanes divided into 2 lanes each way would have the following problems,

1) No central median.

That's not really a problem. A well designed fence can be just as effective.

2) No (or limited) emergency stopping lanes.

Vehicles are much more reliable nowadays - continuous emergency stopping lanes aren't really needed.

A speed limit significantly lower than 110km/hr would then be required for safety reasons which would limit it's effectiveness as an alternative to Port Wakefield Road.

Just being free of traffic lights will make it more desirable than Port Wakefield Road. And the objective isn't to clear Port Wakefield Road, but merely to provide an alternative.

Aidan, must you question absolutely bloody everything?

Shuz wrote:
The expensive cost of the Northern Connector is largely attributed to the fact that it requires a lot of property acquisition.

Does it really? I thought it was mostly saltpans that are being abandoned anyway!

The salt-pans is currently owned by the salt-making company - whoever that is. There is a planned sale of the lands to Delfin Land Lease (for the proposed 20,000 homes housing development) and the Land Management Corporation and DTEI - for necessary infrastructure works associated with the development - both care of SA Government. DTEI specifically will need to buy out the road corridor off Delfin/LMC - and they also have to buy properties in the way of the Connector's path - horticulture/agriculture industries surrounding Virginia, part of Globe Derby Park, Bolivar Treatment Plant, wetlands regions owned by Salisbury Council, homeowners. There's a lot of people affected.

The section of South Road between the PR Expressway and GJ Road is already looking to cost at least $750m, just for a meagre 3km or so section of road. South Road from the Southern Expressway to the PR Expressway is 22km - quick math - that's $5.5b to do the entire South Road, more really because propety is more expensive and subdivided into smaller allotments within the inner-city.

Where did you get the $750m figure from? That's a quarter of a million dollars per metre! How much are they planning to widen the road?

Here, that's where.http://www.sensational-adelaide.com/for ... ?f=9&t=263

Northern Expressway was always planned to have 3x3 lanes. This was factored in from the start. They've built it 2x2 to accomodate the demand it requires upon its opening, and have the land provision for third lanes when the demand rises. This provision significantly reduces construction costs in future when its needed.

What was the third set of 3 lanes planned to be for? Or do you mean 3+3 lanes?

I meant 3+3. It's the same thing.

Now could you stop giving everyone grief and not nit-pick at all the tiniest details? :wank:

Aidan wrote:There's nothing new about converting a road from 2+2 to 4+4+2(rail). Perth's done something similar. So has England (when the A2 / M2 was upgraded and a new high speed rail line constructed beside it).

We must plan for the future - but that doesn't mean we should build it all in one go.

With the exception of some bridges, Perth arterial road network under the Stephenson Plan (Kwinana/Mitchell fwys, Roe/Tonkin/Reid hwys) has not been built as 4-lane (or more) on a single carriageway with a second carriageway added later. Where 2 or more lanes were required in each direction they have been built as dual carriageway with additional lanes added as necessary according to demand.

I agree that it is most likely unnecessary to build initially to an 8-lane freeway (4 lanes in each direction) and question the initial need for all the interchanges (see my comments in this thread a couple of pages back) however a dual carriageway road with capacity to expand the carriageways as necessary seems the most logical starting point and is consistent with the expansion of the arterial road network in Perth.