[COM] Southern Expressway Duplication | $445m | 22km

[Aidan]

Here's the full image; looks like the expressway actually then sinks under as it goes beneath the Main South Road bridges to go into the Sturt Road underpass. Which would explain the slip lanes diverging before the bridges so that they could actually then merge with the MSR slip lanes for the underpass.

I'm guessing it's more likely to be for Flinders Drive than Sturt Road, though it's possible that the slip lanes for the two could be combined.

The need for the southbound bridge over the junction is a bit puzzling, though I'm guessing it's so that traffic from Flinders Drive to the Expressway doesn't have so much lane changing to do. Stranger still is the road branching off the southbound Expressway. I suppose it could be to enable buses from Flinders to serve that stretch of Marion-Flagstaff Road on their way to Marion Shopping Centre, but if that's so important then why don't they alter the current intersection to permit hook turns?

[Aidan]

they should build overpasses along south road instead of tunnels/underpasses... it would be much cheaper and we get more bang for our bucks.

Overpasses are generally better in commercial and industrial areas, but in residential areas they're visually intrusive and too noisy.

an overpass from cross road to daws road would speed things up

The area is suitable, but a mile long overpass would be a ridiculous waste of money. A more sensible alternative is an overpass over Daws Road, plus a few intermediate bridges over South Road to eliminate all the traffic lights and give pedestrians a safe way to cross.

as would an overpass from anzac hwy to grange road.

Much of that is through a residential area, where an overpass would be far too disruptive.

[Aidan]

As there is little land acquisition at the extreme ends, the governmet deals with less public backlash whilst also showing the wider community that they are doing stuff.

The cynic in me thinks that the govt may wait till after the election and seriously consider tolls for the more expensive inner urban bits.

You can't just build a 2 billion dollar road, and have idiots driving along it in peak hour who could easily be on the train or bus. For the most expensive sections of road, you need to send the price signal that the people using it are the people who actually need to use it.

I don't think putting a price signal on an existing road is the right solution, particularly if it's one that residents and businesses are located along.

What we need is a subway, so that the train becomes a more attractive option and runs more frequently. If South Road is still congested after that then maybe we should start thinking about price signals - but it's not appropriate while our public transport's so inadequate.

[Hooligan]

the CBD is generally the destination for commuters.

I don't agree

[muzzamo]

I don't think putting a price signal on an existing road is the right solution, particularly if it's one that residents and businesses are located along.

The most expensive inner-city parts are likely to be tunnels, not existing road.

What we need is a subway, so that the train becomes a more attractive option and runs more frequently. If South Road is still congested after that then maybe we should start thinking about price signals - but it's not appropriate while our public transport's so inadequate.

You clearly have no idea regarding the required densities to make subways viable. It would barely be viable in our CBD.

[muzzamo]

Overpasses are generally better in commercial and industrial areas, but in residential areas they're visually intrusive and too noisy.

Yep if you look at every other major inner city road project in Australia almost all of them have been tunnels. Sydney has dozens of them now.

[skyliner]

it is always better to spend the money on 'something else' no matter what is proposed. It seems to come to urgency, priorities, costs, demand and outcomes from the spending.

Good to hear even a proposition to change that Darlington situation as well as having the expressway as simultaneously two directional for it's whole length. I travelled this expressway in Jan. and wondered what could have happened to make it one directional at a time. (i was very disappointed at the time).

Overall, the idea looks good in the face of certain greater demand from increased population. Glad to see a Darlington interchange as well. I looked at that as a future bottleneck as it is.

After all, the proposal is a continuation of the development through the metro area of a high class road.

SA - STATE ON THE MOVE

[AtD]

Guys, can we keep this thread on topic please?

I used to commute from Salisbury to Flinders for a temp job. One thing that was very obvious is that there is almost no counter-peak traffic south of Richmond Rd. I remember some mornings driving south over the Cross Rd bridge to see a sea of stationary traffic heading north and not being able to see another single car heading south.

On that reasoning I think this is nowhere near the highest priority for transport in the state.

[Hooligan]

correct me if im wrong but isnt the:
Green line the Southern Expressway
Red line Main South road
and the yellow line Marion road?

[Splashmo]

correct me if im wrong but isnt the:
Green line the Southern Expressway
Red line Main South road
and the yellow line Marion road?

I think you're right. We've been looking at it back-to-front.

But three lanes down to two? Eugh.

It might not be our biggest transport priority, but let's face it - it's a project that has to happen at some stage.

[drsmith]

correct me if im wrong but isnt the:
Green line the Southern Expressway
Red line Main South road
and the yellow line Marion road?

Correct.

The render commences from a position just south of the South Road/Flinders Medical Centre intersection and faces southwest.

South Road/Sturt Road would presumably be a different project. Perhaps make South Road 6x6 lanes there .

Going from 1x3 lanes to 2x2 lanes does seem a bit silly (if that is what is suggested) as that would reduce peak capacity but perhaps that's all the road reserve allows.

Whoever did that render did it in a hurry. One of those bridges is surplus to requirements.

[Aidan]

correct me if im wrong but isnt the:
Green line the Southern Expressway
Red line Main South road
and the yellow line Marion road?

I think you're right. We've been looking at it back-to-front.

As that's the way I was always looking at it, I'm puzzled - what did you previously think each of the roads were?

But three lanes down to two? Eugh.

No, that's actually very sensible if traffic's free flowing. If there were more lanes, the merging traffic from Marion road would slow southbound traffic down. And northbound a third lane is not necessary if the traffic can flow freely onto South Road.

What's of much more concern is that four lanes of South Road are being reduced to two.

It might not be our biggest transport priority, but let's face it - it's a project that has to happen at some stage.

Agreed, although it doesn't have to happen like that. For instance there could instead be another superway above South Road through Darlington.

[rhino]

It might not be our biggest transport priority, but let's face it - it's a project that has to happen at some stage.

Pat Conlon explained this on the radio this evening. The Feds have thrown some money towards the Darlington Interchange, apparently, as part of their money-for-freight-transport-routes thing. Conlon said, and I agree, that making a proper freeway-style interchange into a road that changes traffic direction twice a day would be a nightmare, so it makes sense to duplicate the Southern Expressway as part of the Darlington Interchange project, which is partly federally funded and can't really go ahead unless the duplication is done.

[rhino]

well if dunstan had not totally opposed the MATS plan in the 60's and played politics with out strategic infrastructure planning all would be well in adelaide.

Oh please! I suspect I've told you this before zap, but it was Tonkin who killed off the MATS plan - he sold off the land. Stop trying to sell us crap.

[Splashmo]

As that's the way I was always looking at it, I'm puzzled - what did you previously think each of the roads were?

For some reason I thought it was where the expressway splits into South Road and Marion Road, so looking north-east. Very strange.