[U/C] M2 North-South Motorway

[Patrick_27]

Reckon we'll see changes to the Gallipoli Underpass in the future?

The goal is supposed to be 3 lanes in each direction for the North-South Motorway. It would seem silly to leave this choke point where it would merge to 2 lanes for one crossing.
I think it will struggle to fit within the current hole also. I say it will be widened on the east side by one lane width and the other required lane will be found within the existing median and bike lanes etc.

My understanding is they'll be widening the cut for Gallipoli Underpass to the East; which shouldn't be too difficult considering you can close the underpass off and re-direct traffic through the exit lanes, and similar to the Southern Expressway duplication simply extent the fixtures.

I also believe that Gallipoli Underpass will be the beginning of the trenched motorway heading North (correct me if I'm wrong).

[drsmith]

A future reconfiguration option for the Gallipoli Underpass could be for 3 lanes in one direction and 2 lanes in the other. This has been the recent widening strategy along sections of the Kwinana/Mitchell Freeway corridor in Perth with additional lanes being added on the outbound (away from the CBD) carriageway only.

A 5'th lane could also potentially operate as a variable direction peak lane. This was how a lane operated on the Narrows Bridge just south of Perth prior to bridge duplication. The speed limit for this was 80 km/h.

While obviously not 3 lanes in each direction, these options could buy the existing structure time at limited expense. Beyond that, the only practical alternative I can see is underpass duplication which would obviously be at great expense. A lack of foresight it was not to make the existing structure 3 or so metres wider.

The section of south Road across Regency Road (between the Superway and T2T) seems to be lower priority in terms traffic demand from the corridor review but it will over time become a bottleneck between two expressway sections and I wonder how well that will go. The most cost effective means in terms of construction cost would be for a further extension of T2T to include this section as previously noted (pages 95 and 96 of this thread). Further to that, I note that the structure planned at Regency Road is a bridge and not a trench as I'd previously commented.

Politically, construction of the section near Torrens road is not scheduled to get under way till around the federal election. Possible contract cost savings from the Northern Connector and the upcoming federal election make connecting T2T to the Superway as part of T2T a possibility.

[phenom]

The Gallipoli Underpass, whilst a very useful piece of infrastructure, always struck me as a bit of 'pragmatic' development. Whilst it clearly would always form a key part of any future non-stop North-South Corridor I honestly believe the Rann Government at the time (quite fairly) assumed that the completion of the non-stop corridor would be so far away (and possibly effectively 'never') as to make it wasteful to do three-lanes each way from the get go - or even incur the costs of building it 'for six' in future in regards to the bridge infrastructure.

It's a little harder to imagine now but in 2006 infrastructure spending in Australia generally, and certainly in SA, was just recovering from basically a decade or two of nothing significant. Federal funding for major (road) infrastructure was certainly not seen as 'likely'. Hence why even in 2008/9 with the GFC there were few plans 'shovel ready' for money to be put into with some states worse than others... NSW being notorious for being in such a shambles they couldn't even submit any projects for funding consideration at one point.

The irony now is that continued economic problems (globally, with obvious local ramifications) is probably the best bet for SA to get this all done by 2030 or so because the current/future Federal Govts are very likely to be forced into massive infrastructure spending to stimulate the economy and the State now has an actual plan of sorts on how to achieve the long sought after non-stop NS corridor.

Edit: To add that I was 'somewhat involved' in the farcical attempts of the State's infrastructure plan through the mid 2000s and I don't remember even a flicker of a hope that it would involve actual realisation of more than a small part (mainly the far northern side) of the NS corridor. It was flat out talking about augmentation of tiny ports and intermodals.

[claybro]

And yet years after the Gallipoli underpass we were still at it. Despite hundreds of millions spent on the super way, there is a section of the northbound carriageway that is only 2 lanes. So at 90km/h there is a sudden merge at the top of the elevated roadway, before it widens into 3 lanes again. In years to come this will cause huge issues. Surely by the time of the super way plan, it would have been evident it was part of a bigger eventual motorway requiring 3 lanes like the rest of it.

[drsmith]

And yet years after the Gallipoli underpass we were still at it. Despite hundreds of millions spent on the super way, there is a section of the northbound carriageway that is only 2 lanes. So at 90km/h there is a sudden merge at the top of the elevated roadway, before it widens into 3 lanes again. In years to come this will cause huge issues. Surely by the time of the super way plan, it would have been evident it was part of a bigger eventual motorway requiring 3 lanes like the rest of it.

I looked at that yesterday for comparison purposes with the Anzac Highway underpass and noted the shoulder width there can support an additional lane.

2 lanes northbound from South Road + 2 lanes northbound from the Port Road ramp presently merge a short distance downstream into 3 lanes. This could be easily reconfigured into 3 + 2 merging into 4 given the width of the shoulders there. 4 lane tie-ins in both directions are supported by the Northern Connector design.

The Anzac Highway underpass may support 3-lanes in each direction if it's done this tight,

https://www.google.com.au/maps/@-31.905 ... a=!3m1!1e3

That bridge deck in the above example I suspect is around 16m wide after taking into account 4x3.5m lanes. That section of Roe Highway east of Perth carries a high volume of overall traffic including a mix of heavy transport as it's presently the main freight route to/from the north and east. It has a speed limit of 100km/h and it's tight at that speed, perhaps a little too tight with walls on the outside.

Fortunately for the above section of road pictured, that bridge is ultimately planned to be duplicated to provide 3-lanes in each direction much more comfortably. It may not however meet current design standards for its present 4-lane operation. Later 4-lane overpasses on Perth's highway network which are also designed to be duplicated for 6-lane ultimate design are wider as shown in the following example from the early 2000's.

https://www.google.com.au/maps/@-32.003 ... a=!3m1!1e3

[ChillyPhilly]

From memory, the Superway was built 'with provision for widening'. The scope of that and how much it translated, is another story.

[The Scooter Guy]

The former Sizzler building (cnr Sturt Rd/Main South Rd) is now being demolished.

[OlympusAnt]

Good riddance.

[SouthAussie94]

There have been nights works on South Road at Darlington between Sturt Rd and Flinders Drive for the last few nights. Its difficult to see exactly what they're doing but it appears it may be the beginnings of service relocation.

Does anyone have more info?

[ChillyPhilly]

There have been nights works on South Road at Darlington between Sturt Rd and Flinders Drive for the last few nights. Its difficult to see exactly what they're doing but it appears it may be the beginnings of service relocation.

Does anyone have more info?

I'll be driving that way on Saturday evening, so I'll try and have a look.

[Waewick]

driving down Soth Road yesterday , where it is still two lanes between Cross Roads and Tonsley, I noticed that they are still allows construction of new buildings to go up.

If the whole road is eventually going to be upgraded, why on earth are we allowed developments to occur?

[Ben]

driving down Soth Road yesterday , where it is still two lanes between Cross Roads and Tonsley, I noticed that they are still allows construction of new buildings to go up.

If the whole road is eventually going to be upgraded, why on earth are we allowed developments to occur?

I have been wanting to know this answer for years. They are about to start construction on the corner of South and Daws road. One of the biggest bottlenecks. Who on earth is allowing development. That land has been vacant for years the government should have purchased it and atleast improved the intersection until the full upgrade can be completed. Such short term thinking.

[Llessur2002]

But how long do we allow land to remain vacant for? The Port Road area of South Road has looked like a ghetto for the past 2-3 years awaiting the T2T works. Upgrades to some stretches of South Road could potentially be years, if not decades away. Do you let an area fall into ruin just because it might be upgraded at some point in the future? Unless there's an absolute concrete plan in place for the works to start then I can't see how you can hold back development indefinitely.

[Goodsy]

But how long do we allow land to remain vacant for? The Port Road area of South Road has looked like a ghetto for the past 2-3 years awaiting the T2T works. Upgrades to some stretches of South Road could potentially be years, if not decades away. Do you let an area fall into ruin just because it might be upgraded at some point in the future? Unless there's an absolute concrete plan in place for the works to start then I can't see how you can hold back development indefinitely.

We have vacant land awaiting development all over Adelaide, Montague Road has been left wide since the MATS plan

[claybro]

This is a pet hate of mine for years. Concrete plan or not, it has been widely circulated in transport terms, the south road route (in the southern section at least) was the preferred option for over a decade now. Why they have held off on the actual plan for so long...who knows? What we do know, is now we have to pay back whoever is developing this land, a significant amount more for the improvements/ loss of business/ relocation bonus..etc. Just buy the whole corridor, lease back whatever operation is along it, maintain what is vacant. If there was a cohesive plan in place, even if it is to take 30 years...no one can claim to have been kept in the dark and tens of millions would be saved.