[U/C] M2 North-South Motorway

[rev]

The longest road tunnel in the world in Norway, is 24km long.
The Seikan Tunnel in Japan is a railway tunnel that is under the seabed. It's nearly 54km long, of which nearly 24km is undersea.

There's lots of road tunnels between 20-10km in length.

Here the RAA was talking about a tunnel of a mere 6km in length.
If China and various European countries can build tunnels at least twice as long, I'm pretty sure thing's like ventilation and safety while obvious aspects, are not a major issue that prohibits road tunnels.

[koalaboy]

The longest road tunnel in the world in Norway, is 24km long.

I had a look at google maps and this tunnel saves about 30km of trip length and 45 minutes travel time. The Heyson tunnels are very short, yet they also greatly improve travel time and reduce trip length. Massive costs (operating and constructing), but massive benefits (more than half trip length, more than half trip duration) In both of these cases there are no entry or exit points along the length of the tunnel. There is a theme for when tunnels are used and South Rd doesn't follow that theme.

A South Rd tunnel may save a bit of travel time due to the lack of intersections, but the trip length and travel time would be exactly the same as a series of overpasses / underpasses or a fully elevated road. At least the series of overpasses / underpasses can relativly cheaply have interchanges and ramps installed. Also, most people on South Rd are not travelling end to end, they want to turn off to head into the city or other places along the road. A 6km tunnel with no on or off access would be empty (not quite, but really not worth the mega dollars).

I'm pretty sure thing's like ventilation and safety while obvious aspects, are not a major issue that prohibits road tunnels.

I'm farily sure that's a big part of their construction and operating expense. I agree, the technology has come a long way and they are virtually bomb proof. Previously fires would result in tunnels being shut for months for repairs, but now they just scrub off the soot and reopen.

[Jim Boukas]

So you wouldn't care if a big arse elevated highway was built on your front door step?

Plus what's wrong with a tunnel?

HMMM now let me think would i prefer 1000's of cars passing my house every day or a few 100, gee the less traffic might even add value to my place, Crawf you raise a very interesting point, 1000's of cars vs. 100's and increased property value????

Can I get back to you on that on that one??

[Nort]

So you wouldn't care if a big arse elevated highway was built on your front door step?

Plus what's wrong with a tunnel?

HMMM now let me think would i prefer 1000's of cars passing my house every day or a few 100, gee the less traffic might even add value to my place, Crawf you raise a very interesting point, 1000's of cars vs. 100's and increased property value????

Can I get back to you on that on that one??

You really think that having 1000's of cars passing overhead on a roadway that shadows your property and allows them to look down into your back yard would be more appealing than having 1000's of cars passing by behind a fence?

[Jim Boukas]

You really think that having 1000's of cars passing overhead on a roadway that shadows your property and allows them to look down into your back yard would be more appealing than having 1000's of cars passing by behind a fence?

Yes you make a valid point when I’ve driven along elevated freeways at 100+ km/hr i get a really good view of the houses directly below

Are you au fait with the term line of site? in this case since your head height is approximately 200-300 mm above the side barricade that usually runs along an elevated freeway and assuming the freeway is approx 10 m above ground level basic trigonometry would mean the closest house you'd see is about 100 m away from the freeway, I’m not sure about you but travelling at 100 km/hr and trying to look at someone's back yard 100 m away might not be that easy.

[drsmith]

The inescapable truth with South Road is that it will be impossible to deliver a free-flowing solution and maintain local access on the one corridor. Grade seperation at existing signalised intersections while retaining property/local street access won't cut it. Some form of signalised control would have to be maintained in order to permit such local access.

Whether it's via tunnel/trench, viaduct or a new ground level route, these will be the only options for a fully free flowing solution.

[drwaddles]

Are you au fait with the term line of site?

I am aware of line of sight but what on earth is line of site?

[Aidan]

You really think that having 1000's of cars passing overhead on a roadway that shadows your property and allows them to look down into your back yard would be more appealing than having 1000's of cars passing by behind a fence?

Yes you make a valid point when I’ve driven along elevated freeways at 100+ km/hr i get a really good view of the houses directly below

Are you au fait with the term line of site? in this case since your head height is approximately 200-300 mm above the side barricade that usually runs along an elevated freeway and assuming the freeway is approx 10 m above ground level basic trigonometry would mean the closest house you'd see is about 100 m away from the freeway, I’m not sure about you but travelling at 100 km/hr and trying to look at someone's back yard 100 m away might not be that easy.

Not all vehicles are cars, not all users are i the driver's seat, and a 10m height is excessive (as the normal limit for overheight vehicles is 4.9m).

Anyway the main problem isn't being overlooked, nor being overshadowed by the elevated road itself. The problem is the noise. 100km/h traffic is very noisy. Barriers reduce the noise but they don't eliminate it. And being elevated means less of the sound will be blocked by the surrounding buildings.

[crawf]

The longest road tunnel in the world in Norway, is 24km long.

I had a look at google maps and this tunnel saves about 30km of trip length and 45 minutes travel time. The Heyson tunnels are very short, yet they also greatly improve travel time and reduce trip length. Massive costs (operating and constructing), but massive benefits (more than half trip length, more than half trip duration) In both of these cases there are no entry or exit points along the length of the tunnel. There is a theme for when tunnels are used and South Rd doesn't follow that theme.

A South Rd tunnel may save a bit of travel time due to the lack of intersections, but the trip length and travel time would be exactly the same as a series of overpasses / underpasses or a fully elevated road. At least the series of overpasses / underpasses can relativly cheaply have interchanges and ramps installed. Also, most people on South Rd are not travelling end to end, they want to turn off to head into the city or other places along the road. A 6km tunnel with no on or off access would be empty (not quite, but really not worth the mega dollars).

I believe a tunnel from say Regency Road to Anzac Highway would still be heavily used considering there are thousands of people travelling north-south and vise versa every single day. Would it be possible to have a exit point at Port Road for people travelling to the city?

[Aidan]

The inescapable truth with South Road is that it will be impossible to deliver a free-flowing solution and maintain local access on the one corridor. Grade seperation at existing signalised intersections while retaining property/local street access won't cut it. Some form of signalised control would have to be maintained in order to permit such local access.

Whether it's via tunnel/trench, viaduct or a new ground level route, these will be the only options for a fully free flowing solution.

What precisely do you think the problem is with having a local traffic lane as well as two nonstop lanes each way?

[drsmith]

What precisely do you think the problem is with having a local traffic lane as well as two nonstop lanes each way?

None in principal, but this is still a 2-corridor solution.

[Aidan]

What precisely do you think the problem is with having a local traffic lane as well as two nonstop lanes each way?

None in principal, but this is still a 2-corridor solution.

No it isn't, the entire road would remain in a single corridor. Nothing more substantial than a dashed line of reflective paint would separate the local traffic lanes from the rest of the road, except at around major intersections where the nonstop lanes would go onto the overpass/underpass while the local traffic lanes split off to go to the traffic lights.

[AtD]

I do agree with it, but I am amused by the literal NIMBYism in this thread. Uncharacteristic of this forum.

[drsmith]

No it isn't, the entire road would remain in a single corridor. Nothing more substantial than a dashed line of reflective paint would separate the local traffic lanes from the rest of the road, except at around major intersections where the nonstop lanes would go onto the overpass/underpass while the local traffic lanes split off to go to the traffic lights.

If this is a workable solution, where else in Australia has it been done ?

[Aidan]

No it isn't, the entire road would remain in a single corridor. Nothing more substantial than a dashed line of reflective paint would separate the local traffic lanes from the rest of the road, except at around major intersections where the nonstop lanes would go onto the overpass/underpass while the local traffic lanes split off to go to the traffic lights.

If this is a workable solution, where else in Australia has it been done ?

I don't know of any Australian examples; I got the idea from Britain.