Gepps Cross Intersection

[Eurostar]

As many of you know the Gepps Cross intersection is a busy intersection where Port Wakefield Road, Main North Road and Grand Junction meet, during certain times traffic is heavy. By now you'd think the State Government would have fixed it. Here is some options:

Option 1

Main North Road goes over the top
Grand Junction Road goes under the intersection
Port Wakefield Road meets with the intersection

Option 2

Main North Road goes under the intersection
Grand Junction Road goes over the intersection
Port Wakefield Road meets with the intersection

Option 3

Main North Road goes under the intersection
Grand Junction Road goes under Main North Road and intersection
Port Wakefield Road goes over the intersection, traffic merging with Main North Road (south) or vice versa

[Aidan]

As many of you know the Gepps Cross intersection is a busy intersection where Port Wakefield Road, Main North Road and Grand Junction meet, during certain times traffic is heavy. By now you'd think the State Government would have fixed it.

They released a plan, but then they seemed to decide to concentrate exclusively on South Road instead. Unfortunately it's an insanely overengineered plan for South Road that's likely to paralyse everything else for a long time.

Here is some options:

Option 1

Main North Road goes over the top
Grand Junction Road goes under the intersection
Port Wakefield Road meets with the intersection

Option 2

Main North Road goes under the intersection
Grand Junction Road goes over the intersection
Port Wakefield Road meets with the intersection

Option 3

Main North Road goes under the intersection
Grand Junction Road goes under Main North Road and intersection
Port Wakefield Road goes over the intersection, traffic merging with Main North Road (south) or vice versa

How about Grand Junction Road going under the intersection and nothing else*?

With less time on red to let the Grand Junction Road traffic through, the intersection wouldn't cause such long delays.


* Nothing else in the short term, but the underpass design shouldn't be incompatible with the later addition of an overpass to Port Wakefield Road, nor one to Main North Road.

[claybro]

Agree that Grand Junction Road should be the priority at this intersection. Surely though an overpass would be easier and less expensive than an underpass? It is a wide intersection with no residential immediately adjacent. This should be considered in view of Grand Junction road eventually becoming a non stop outer ring route. With the opening of the Superway and the eventual completion of the Northern connector, a lot of traffic that currently converges at this intersection from Pt Wakefield Rd and even Main North Rd will no longer need to use this intersection making further grade separation beyond separating Grand Junction from the rest not imperative.

[[Shuz]]

Agree that Grand Junction Road should be the priority at this intersection. Surely though an overpass would be easier and less expensive than an underpass? It is a wide intersection with no residential immediately adjacent. This should be considered in view of Grand Junction road eventually becoming a non stop outer ring route.

Have you not heard of the Port River Expressway?

Not to mention there is sufficient land either side of the Montague Road corridor to transform that into a continuation of the Port River Expressway, as originally intended for the Dry Creek Expressway as part of the 1968 MATS Plan. That would be a far more suitable, and cheaper alternative, than making Grand Junction Road a non-stop route.

I hate that word. Non-stop. Just call it what its meant to be, a bloody freeway. Why all the scare with freeways on here?

[claybro]

Agree that Grand Junction Road should be the priority at this intersection. Surely though an overpass would be easier and less expensive than an underpass? It is a wide intersection with no residential immediately adjacent. This should be considered in view of Grand Junction road eventually becoming a non stop outer ring route.

Have you not heard of the Port River Expressway?

Not to mention there is sufficient land either side of the Montague Road corridor to transform that into a continuation of the Port River Expressway, as originally intended for the Dry Creek Expressway as part of the 1968 MATS Plan. That would be a far more suitable, and cheaper alternative, than making Grand Junction Road a non-stop route.

I hate that word. Non-stop. Just call it what its meant to be, a bloody freeway. Why all the scare with freeways on here?

Yes Shuz, I am aware of the Montague road part of MATS, and that does have its merits, joining on to the PREXY, and I am in two minds for the Northern Ring. But the Eastern End of Montague road is now heavily residential and commercial. Grand Junction not so much. The aim being to get transport from the end of Portrush to the Northwest suburbs as easily as possible. I thought Grand junction road provided a more direct route for that.

[Aidan]

Agree that Grand Junction Road should be the priority at this intersection. Surely though an overpass would be easier and less expensive than an underpass? It is a wide intersection with no residential immediately adjacent. This should be considered in view of Grand Junction road eventually becoming a non stop outer ring route. With the opening of the Superway and the eventual completion of the Northern connector, a lot of traffic that currently converges at this intersection from Pt Wakefield Rd and even Main North Rd will no longer need to use this intersection making further grade separation beyond separating Grand Junction from the rest not imperative.

There is housing on the east side, and within 200m of the intersection it's on both sides of the road. But despite that an overpass is probably the better choice if no further upgrades will be needed beyond that.

We shall soon see the effects of the Superway opening, but I doubt it will make much difference, as most of the traffic that would use it is likely to turn off Port Wakefield Road at Cavan Road at the moment.

And I'm far from convinced of the need to make Grand Junction Road a nonstop route, let alone the rest of the outer ring.

Have you not heard of the Port River Expressway?

Not to mention there is sufficient land either side of the Montague Road corridor to transform that into a continuation of the Port River Expressway, as originally intended for the Dry Creek Expressway as part of the 1968 MATS Plan. That would be a far more suitable, and cheaper alternative, than making Grand Junction Road a non-stop route.

I hate that word. Non-stop. Just call it what its meant to be, a bloody freeway. Why all the scare with freeways on here?

There's no scare, but most of us don't want one within Adelaide's inner suburbs. And unlike freeways, nonstop corridors need not be limited access.

As for Montague Road, extending it to the PREXY would be worthwhile, but the costs of grade separating the entire road would greatly outweigh the benefits. The MATS Plan had it as an expressway to connect with the Modbury Freeway. As the latter will never be built, it makes sense for Montague Road to remain a normal suburban arterial.

[[Shuz]]

Montague Road is not the inner suburbs. That's laughable if you believe it is.

I concede there is one small complication to extending the PREXY to Montague Road, and that is that the new Dry Creek Railway Depot stands in the way. You would require a diversion north or south of the depot, which would require costly property acquisition of industrial warehouses. However this is not impossible.

RE: Modbury Freeway - I firmly believe you are wrong. The Modbury Freeway can still be, and should be built. It is imperative to relieving the congestion off both Lower North East and North East Roads. In conjunction with this, it would actually assist in the reinstatement of the tram network which used to traverse both these routes and beyond. By eliminating and reducing congestion on both these roads and redirecting the traffic onto the new freeway, not only would you reduce travel times for commuter and freight traffic by providing (and I hate to say it) a non-stop, fast flowing route into and out of the city,it would actually favour the reliability of a potential tram service, which would have less traffic congestion to compete with. Hell, I'd go so far as to suggest tram-only lanes on both these roads if the Modbury Freeway were built.

This has gone a little off-topic from Gepps Cross, but nevertheless, assuming all that, I quite liked the suggestion a couple years ago which called for southbound traffic on Port Wakefield Road to turn right onto a new road along the boundary of the Gepps Cross drive in and turn right on Main North Road at a new T junction. But further to this, I'd suggest also, that the new road extend along Kara and Tepko Streets on the State Sports Park land (owned by Government) to connect with a new T Junction at Grand Junction Road, so that all traffic wishing to turn right onto either Port Wakefield or Main North Roads use the new road, and right hand turns at the Gepps Cross Intersection from westbound traffic on Grand Junction Road would be banned. (I believe this is why most of the crashes occur?)

[Aidan]

Montague Road is not the inner suburbs. That's laughable if you believe it is.

Would you regard Mawson Lakes as one of the outer suburbs? To me that would be laughable. When I first came here the inner suburbs ended at Grand Junction Road, but since then they have expanded.

I concede there is one small complication to extending the PREXY to Montague Road, and that is that the new Dry Creek Railway Depot stands in the way. You would require a diversion north or south of the depot, which would require costly property acquisition of industrial warehouses. However this is not impossible.

I was thinking an elevated road would be more appropriate.

RE: Modbury Freeway - I firmly believe you are wrong. The Modbury Freeway can still be, and should be built. It is imperative to relieving the congestion off both Lower North East and North East Roads. In conjunction with this, it would actually assist in the reinstatement of the tram network which used to traverse both these routes and beyond. By eliminating and reducing congestion on both these roads and redirecting the traffic onto the new freeway, not only would you reduce travel times for commuter and freight traffic by providing (and I hate to say it) a non-stop, fast flowing route into and out of the city,it would actually favour the reliability of a potential tram service, which would have less traffic congestion to compete with. Hell, I'd go so far as to suggest tram-only lanes on both these roads if the Modbury Freeway were built.

Nice try, except that:
• There is no environmentally acceptable route available for a freeway.
• It is perpendicular to the main axis of freight traffic
• Apart from the sections E of Hope Valley/Modbury, (which the freeway wouldn't alleviate) commercial vehicles only comprise between 2.5% and 3% of the total traffic
• How would you enable the City to cope with the extra traffic? The modal shift onto trams would not be anywhere near as big as the shift from the O-bahn to cars on the freeway.
• ISTR reading that before the O-bahn was built, North East Road was 3+3 lanes. This suggests it might be possible to add tram only lanes without having to divert the traffic away.

Freeways tend to move traffic congestion problems rather than solve them. If congestion on those roads is a problem, extending the O-bahn right into the City is likely to be a much more effective solution.

[monotonehell]

Nice try, except that:
• There is no environmentally acceptable route available for a freeway.
• It is perpendicular to the main axis of freight traffic
• Apart from the sections E of Hope Valley/Modbury, (which the freeway wouldn't alleviate) commercial vehicles only comprise between 2.5% and 3% of the total traffic
• How would you enable the City to cope with the extra traffic? The modal shift onto trams would not be anywhere near as big as the shift from the O-bahn to cars on the freeway.
• ISTR reading that before the O-bahn was built, North East Road was 3+3 lanes. This suggests it might be possible to add tram only lanes without having to divert the traffic away.

Freeways tend to move traffic congestion problems rather than solve them. If congestion on those roads is a problem, extending the O-bahn right into the City is likely to be a much more effective solution.

You forgot;
• Switching the OBahn for a tram to the NE would add more traffic to the road system. Because the tram can not offer door to door service for people away from the track, therefore pushing more people into cars.

[Aidan]

You forgot;
• Switching the OBahn for a tram to the NE would add more traffic to the road system. Because the tram can not offer door to door service for people away from the track, therefore pushing more people into cars.

No, I didn't forget it. Shuz did not propose replacing the O-bahn with trams - only the buses on NE and LNE Roads.

[monotonehell]

You forgot;
• Switching the OBahn for a tram to the NE would add more traffic to the road system. Because the tram can not offer door to door service for people away from the track, therefore pushing more people into cars.

No, I didn't forget it. Shuz did not propose replacing the O-bahn with trams - only the buses on NE and LNE Roads.

The Obahn was built on the proposed Modbury Freeway's route. I was assuming that Shuz was reccomending trams on the road and a freeway instead of the OBahn.

[[Shuz]]

My position is clear. I favour;

Demolishing the O-Bahn Busway.
Along the O-Bahn corridor, and McIntyre Road, construct the Modbury Freeway, as per the 1968 MATS Plan.
Construction of a train line in the central median of the new Modbury freeway, similar to the Mitchell and Kwinana Freeways in Perth.
Reinstating trams along Lower North East and North East Roads.

[Norman]

Are you sure a 2+2+2 will fit along the narrow corridor?

[[Shuz]]

Are you sure a 2+2+2 will fit along the narrow corridor?

I was thinking more 3x3 + train.

Also, property acquisition.

[Aidan]

Shuz - Normally at this point I'd say 9 lanes is too many. But South Australians value the Torrens Linear Park so much that even one extra lane would be too many. So instead I'll just ask: why? Is it just because you like freeways? Or are you, despite the evidence, genuinely under the impression that it would be the best solution to the area's transport problems?

Also, does your yearning for the MATS Plan's Modbury Freeway alignment include the northern end (across the Wynn Vale Gullies and through what are now residential suburbs)?