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

[rhino]

Jim, if you consider that the roads coming in from the south include all 5 from Lonsdale Road to Shepherds Hill Road (that's an incredibly wide zone to draw from), then you must also accept that the roads heading north can include all the main roads from Brighton Road (Lonsdale road feeds into this) to Fullarton Road (traffic from Blackwood, where Shepherds Hill Road originates, can also come north via this route). So you have Brighton, Morphett, Marion, South, Goodwood, Belair/Unley, and Fullarton. That makes 7.

In practise, most Lonsdale Road traffic continues to Brighton Road, not South Road, and most Shepherds Hill Road traffic continues on to Sturt Road, not South Road. And these two routes make the case for induced demand.

Currently, city-bound traffic from Lonsdale Road uses (mainly) Brighton Road and Anzac Highway. Put a freeway down the South Road corridor and that Brighton/Anzac traffic will head for the freeway.

Currently, city-bound Blackwood/Hawthorndene/Belair/Coromandel traffic uses mainly Old Belair Road, and then Belair Road or Fullarton/Glen Osmond Roads to reach the city. Put a freeway down the South Road corridor and guess where all that traffic will go?

And there you have your Induced Demand.

[Jim Boukas]

Rhino, people are going to leave Glen Osmond Road and Unly road to travel to south road and then turn right to go to the city????

I concede it's 5 a piece, the deciding factor here is that it's easier to do the either ends of south road, because over the years instead of tackling this problem our politicians have, as you know been more interested in doing short duration projects such as building festival theaters, underpasses, tram extensions, Desal Plants and donning tight shorts to boot, now alas it’s a horrendously expensive exercise to get it right!!!

[rhino]

Jim, firstly, yes, people from Mitcham Hills area will use Shepherd Hill Road and a freeway to reach the city rather than Fullarton and Glen Osmond roads, if the freeway is there. They will also stop using the train, because the freeway is there.

Secondly, it is only slightly more expensive to build a freeway in that corridor now now than it was in the 1970s. Prices are relative. It was built-up area then, it's built-up area now. It's only when comparing it to greenfields development that it makes a real difference. If you need to bang your head on a wall to make that sink in, go for it. The really stupid move was the Tonkin government selling off the land that had already been bought.

[muzzamo]

Secondly, it is only slightly more expensive to build a freeway in that corridor now now than it was in the 1970s.

Not convinced of this. Much higher OHS&W requirements, higher tradies wages and Australian property bubble leading to excessively high land prices.

[rhino]

Muzz, fair call re the OHS&W requirements, which were unheard of back in the 70s and therefore could not have been foreseen, any more than we can forsee what will be affecting building costs 40 years from now.

Tradies had to get paid then as they do now. Once gain, however, things such a superannuation payments etc didn't figure into the cost of things back then.

So, I concede that costs have risen, but there is also more money around now than there was then, and the cost of materials is not so different (relatively speaking) now. In fact materials are probably cheaper.

If the land for the MATS plan hadn't been sold off, there would probably be a decent north-south corridor by now. Whether it would be a 110km/h freeway or simply a 60km/h controlled-access road, I don't know, but I'm sure there would be something. No use crying over spilt milk but.

Personally, I'm all for a 60km/h controlled access road rather than a freeway. I drove South Road a few times recently during afternoon peak, and was quite impressed with the pace between Richmond Road and Castle Plaza. If I could have kept going like that I would have been very happy. Keep building those underpasses and overpasses!

[Jim Boukas]

Rhino I was thinking about the concept of ID and would it really effect a hypothetical freeway along south Road, one thing to remember is that the other roads will still be there, so I guess if the majority of the road users initially start using the freeway it probably will get congested, however I would say that a % of them would go back to using the existing roads as they in theory should have less traffic. The commuters I’m thinking of are the ones that don’t necessarily use the whole stretch of south road now, a kind of self leveling type scenario.

With regards to me banging my head on the wall I do that every day as I travel along south road to and from work.

[spiller]

^^^ thats the whole point of a freeway - to decrease travel time for those on the long stretch, and also for those taking the shorter journeys on the now less congested minor roads...

[Jim Boukas]

^^^ thats the whole point of a freeway - to decrease travel time for those on the long stretch, and also for those taking the shorter journeys on the now less congested minor roads...

So based on that then Induced Demand is not then applicable to the hypothetical portion of freeway between Darlington and Regency Park.

WOW if feel like I'm on a merry-go-round

[rhino]

^^^ thats the whole point of a freeway - to decrease travel time for those on the long stretch, and also for those taking the shorter journeys on the now less congested minor roads...

Huh? Spiller your comment points directly at Induced Demand. It sounds like you're saying "Build a freeway and everyone can use it for every journey, long or short, that's going in that general direction". That mentality will choke the freeway as soon as it's built. That is Induced Demand.

[spiller]

Sorry guys, thats NOT what i meant, i should have been more specific but was in a hurry with my post. This is what I meant to say.

Benefits of freeway:

1) reduced travel time during longer journeys for people actually using the freeway
2) reduced travel time during shorter journeys for people using other main roads that are no longer as congested (due to less "longer journey" traffic which now occupies the freeway).


makes sense now?

EDIT: reading my OP again, i never said anything about people using the freeway for shorter trips. I said their short trips will be quicker on the minor roads (i.e. NOT the freeway) which are now less congested.

cheers

[rhino]

Thanks for clearing that up Spuiller, makes much more sense now

[Hooligan]

I'm confused. Who sold who the pumpkin?

[Jim Boukas]

So in summary then ID potentially won't apply to a hypothetical freeway from Darlington to Regency park as some of the short journey travelers will still be using the existing (less congested roads).

So I guess ID would only apply if a freeway was built and the existing roads were removed?

[[Shuz]]

Time to get out the popcorn!

[mattblack]

This government should look at taking one lane away from all the main roads in Adelaide and making them dedicated bus lanes, this will mean that we will be forced to get out of our cars and start using public transport. I vote we stop spending money on encouraging commuters to use their vehicles but instead get them onto public transport a much more cost effective solution.

I’ve got to say that I completely agree with this statement with Adelaide having very wide and open streets. Having lived in London and Amsterdam and recently returned from a holiday in Paris the vast majority of roads through these cities are 1 lane in each direction with the occasional dedicated bus lane thrown in which is why these cities are notorious for their congested roads. There must be a balance though. These cities also have excellent public transport, including metros, trams, buses, trains and excellent dedicated cycling lane provisions but they also have excellent freeway systems around the outskirts of the city centres. It is hard to make comparisons however because the major difference between Europe and us is the built form of the city. European cities and smaller in size and have very high densities making public transport much more efficient, Adelaide is anything but that making P/T harder and less efficient to operate.