News & Discussion: Roads & Traffic

[AtD]

camaro68: I suggest you have a read of the first several pages of this thread. To steal a quote, saying we can widen roads to cure congestion is like saying you can widen your belt to cure obesity. The notion that building new, faster, wider commuter motorways can reduce the number of trucks, reduce pollution and reduce wear on cars is complete rubbish, simply because of the law of induced demand.

It's been demonstrated in both Adelaide and interstate. Notice that every motorway that leads to any of the major cities in the country is congested, even when they're only a few years old. You can take a look at how the Southern Expressway and Mt. Barker Freeway served to encourage low density housing in far away places such as Willunga or Mt. Barker where the population is forced, though lack of alternatives, to drive into the city on a daily bases for work. Look how Cross Road, Portrush Road and Glen Osmond Road got dramatically worse after the new tunnels. Look how South Road became an order of magnitude worse after the Southern Expressway.

Conversely, imagine how much easier your drive from Noarlunga to Gawler would be if there were 10, 20, 30 thousand fewer people on the road. What's an easy way to achieve this? Get as many of the city-bound commuters out of their cars and onto buses or trains by providing them with a fast, frequent and reliable service. You, as a motorist, will benefit as there will be less traffic on the road, and unlike a motorway, a railway is less likely to encourage new low density sprawl in far away areas simply because you need to be within walking distance of the rail line to benefit from it - that's where smart urban planning comes into play.

The more apartment buildings we can build on our railway lines, the more people who have trains as a viable choice for commutes, meaning less people on the roads and therefore faster commutes for you. The state and federal governments have acknowledged this with a large piece of funding for public transport and a greater emphasis on high density buildings around it.

This does not mean everyone needs to live in an apartment and take a train to work. Though the simple laws of supply and demand, the more attractive apartments we build, the lower (all things equal) rends and housing costs will be for everyone else. More people who take trains means less traffic for you to deal with!

Everyone wins.

[raulduke]

camaro68: I suggest you have a read of the first several pages of this thread. To steal a quote, saying we can widen roads to cure congestion is like saying you can widen your belt to cure obesity. The notion that building new, faster, wider commuter motorways can reduce the number of trucks, reduce pollution and reduce wear on cars is complete rubbish, simply because of the law of induced demand.

It's been demonstrated in both Adelaide and interstate. Notice that every motorway that leads to any of the major cities in the country is congested, even when they're only a few years old. You can take a look at how the Southern Expressway and Mt. Barker Freeway served to encourage low density housing in far away places such as Willunga or Mt. Barker where the population is forced, though lack of alternatives, to drive into the city on a daily bases for work. Look how Cross Road, Portrush Road and Glen Osmond Road got dramatically worse after the new tunnels. Look how South Road became an order of magnitude worse after the Southern Expressway.

Conversely, imagine how much easier your drive from Noarlunga to Gawler would be if there were 10, 20, 30 thousand fewer people on the road. What's an easy way to achieve this? Get as many of the city-bound commuters out of their cars and onto buses or trains by providing them with a fast, frequent and reliable service. You, as a motorist, will benefit as there will be less traffic on the road, and unlike a motorway, a railway is less likely to encourage new low density sprawl in far away areas simply because you need to be within walking distance of the rail line to benefit from it - that's where smart urban planning comes into play.

The more apartment buildings we can build on our railway lines, the more people who have trains as a viable choice for commutes, meaning less people on the roads and therefore faster commutes for you. The state and federal governments have acknowledged this with a large piece of funding for public transport and a greater emphasis on high density buildings around it.

This does not mean everyone needs to live in an apartment and take a train to work. Though the simple laws of supply and demand, the more attractive apartments we build, the lower (all things equal) rends and housing costs will be for everyone else. More people who take trains means less traffic for you to deal with!

Everyone wins.

always with the induced demand...

[AtD]

Damn that pesky Adam Smith guy.

[Norman]

Don't forget that increasing public transport transport to the system from high-density hubs also increases the amount of workers in the CBD, increasing density there also, which is what we want.

[monotonehell]

Don't forget that increasing public transport transport to the system from high-density hubs also increases the amount of workers in the CBD, increasing density there also, which is what we want.

But what of the increased density around Adelaide Now posters?

[raulduke]

the problem with simple supply and demand analysis is that it typically looks at one factor in isolation ie. ceteris parabis

[Benski81]

the problem with simple supply and demand analysis is that it typically looks at one factor in isolation ie. ceteris parabis

True but not quite, yes first year eco everything is held ceretis parabis to keep it simple but third year eco we look at issues like supply induced demand and other externalities that can and do effect the model. It becomes about more than just shifting two lines on a page and that's where regression analysis and differential calculus come into the picture to make the supply and demand thing a little more 3D. What AtD was saying about supply induced demand for road use is very true, I don't know what the answer to the problem is though.

[Aidan]

The only positive effect I can think of other than what we'd get from upgrading South Road is faster journey times for users - but even that may be temporary, and non users are more likely to be slowed down than speeded up.
But why would we (not necessarily you rhino) want to pay attention to those things.

1 positive effect??? Wake up and smell the coffee dude!!!

You seem to be the one in need of coffee. 1 positive effect in addition to the positive effects that South Road upgrading would give.

Advantages: here’s a few, less trucks on small suburban roads (safety),

But would there be? There would be fewer trucks on urban arterial roads, but I don't think there would be much effect on small suburban roads.

Less pollution to the atmosphere, ergo the less you’re engine is running the less emissions it produces, less wear and tear less stops (Brakes, Clutches etc) and we all know that a vehicle’s highway cycle is more efficient than it’s city cycle. So in summary, cheaper running costs, less emissions and safer suburban roads you do the math???

Firstly, less pollution per vehicle doesn't automatically mean less total pollution.

Secondly, grade separating South Road would produce the same advantages.

If you consider the size of the disadvantages, perhaps a bigger question is why would you?

Apparently Public Transport is the way to go in a city which many PT and Freeway Activists (on S-A) alike have admitted is one of the most low-density cities they have ever seen.

Determine the % of the working population that work in the city, then decide if public transport upgrades is the best option

One thing we must not do is assume that public transport is only suitable for people working in the City.

I thought I'd explained to you that people rejected the MATS plan for a good reason, and that reason has not changed - indeed it's strengthened.

What reason??

Actually there's two reasons: firstly it was too disruptive. Thousands of properties would've been blighted, neighbourhoods would've been ruined, and residential suburbs would've been torn apart, so people didn't want it.

Secondly it was not needed. It was based on forecasts of increasing demand for car travel that failed to recognise that the demand could be reduced by improving the public transport system.

We don't want SA to look like Chicago or California, perhaps the blue rinse brigade that rejected it so many years ago should try travelling down our main roads today it's a joke, it takes me 40 mins to drive from Goodwood to port Adelaide every day, 20 km journey, i travelled 80 km's through the centre of Melbourne at it took me 60 mins, mate do yourself a favour and travel around Melbourne, it's a pleasure to drive there.

The nice thing about Melbourne is it's got a good tram system so there's no need to drive there! And yes, their road system was so bad that they had to resort to tollways under the City which did solve the problem, and the freeways are free flowing even though they're no longer free to use! Some time in the future it will probably be worth building underground tollways in Adelaide too - but at the moment there's not sufficient demand to justify constructing any.

[adam73837]

firstly it was too disruptive. Thousands of properties would've been blighted, neighbourhoods would've been ruined, and residential suburbs would've been torn apart, so people didn't want it.

You focus on the small % of properties that would have had to have been acquired. Compare that with the number of people that would have befited from them daily, THEN if you can still think of a reason that it was absolutely, utterly, horrible you can respond to me .

Secondly it was not needed. It was based on forecasts of increasing demand for car travel that failed to recognise that the demand could be reduced by improving the public transport system.

PT will NOT serve everyone. Private vehicle use is here to stay; you simply can't expect people's lives to revolve around the uncertain timetables of the Adelaide Metro. NOT EVERYONE works in the CBD, and NOT EVERYONE lives within walking distance of everything that their lives revolve around.

BTW, if anyone watches the South Park episode "smug alert" when Cartman is walking through San Francisco, they'll find the similarities between Adelaide and San Francisco quite amusing indeed.

[monotonehell]

BTW, if anyone watches the South Park episode "smug alert" when Cartman is walking through San Francisco,
they'll find the similarities between Adelaide and San Francisco quite amusing indeed.

If you could extract yourself out of the 1950s mindspace for a few minutes; it's funny that you bring up San Francisco.
Read this: http://www.preservenet.com/freeways/Fre ... adero.html and have a think about things. Don't just take the article's word for it, I'm sure they have an agenda of their own, just think about the facts they present.


While some connectors have their purpose, freeways as per the MATS paradigm are a product of early last century's "man against nature" and "engineering it bigger is better" mentality. Since then we've discovered things like induced demand actually mean that freeways aren't such a great idea after all.

Freeway connectors may have their purpose where there are two (or more) discrete areas that see a lot of inter-traffic. When you are talking about cutting swathes of freeway through the grid, you're generally looking at the wrong solution for the wrong problem. All those trucks you talk about going along the metro area's roads are not all going from point A to point B. They are all making quite a number of discrete journeys. If they were all making the same journey, the solution would be a freight train.

A better solution is a number of good roads going in all the directions that people need to go, all sharing the load of traffic. Instead of inducing ALL the traffic down one freeway -- that's asking for congestion (and calls for a bigger freeway).

[Aidan]

firstly it was too disruptive. Thousands of properties would've been blighted, neighbourhoods would've been ruined, and residential suburbs would've been torn apart, so people didn't want it.

You focus on the small % of properties that would have had to have been acquired. Compare that with the number of people that would have befited from them daily, THEN if you can still think of a reason that it was absolutely, utterly, horrible you can respond to me .

Firstly, the properties that would need to be acquired are significant. Just because they're a small percentage of the total doesn't justify ignoring them.

Secondly I wasn't focussing only on the properties that would have had to have been acquired. A bigger problem is the ones that wouldn't be acquired but would still become worse places to live. We don't want the noise and fumes. We don't want neighbourhoods broken up. The MATS Plan was rejected because the public didn't want it, and politically that isthe most important reason you can get.

As for the number of people who benefit daily, more freeways would encourage them to live where they can take advantage of the freeways to commute. This would result in induced traffic, not only driving much further (and so increasing air pollution) but also filling up the freeways, making them less effective. Perth subsequently had to widen some of its freeways, so it's quite likely that Adelaide would have had to do likewise. In other words, the MATS Plan wouldn't even be effective at its own objectives.

Secondly it was not needed. It was based on forecasts of increasing demand for car travel that failed to recognise that the demand could be reduced by improving the public transport system.

PT will NOT serve everyone.

That's a red herring - freeways will NOT serve everyone either.

Private vehicle use is here to stay;

That doesn't mean everybody has to use their vehicle for everything.

you simply can't expect people's lives to revolve around the uncertain timetables of the Adelaide Metro.

I never said you could. And I expect the market share of public transport to remain quite low until normal services are frequent enough for passengers not to need a timetable.

NOT EVERYONE works in the CBD,

NOT EVERYONE who uses public transport goes to the CBD.

and NOT EVERYONE lives within walking distance of everything that their lives revolve around.

But NEARLY EVERYONE lives within walking distance of a railway station or bus or tram stop to enable them to access everything that their lives revolve around.

[paul]

The principle of Induced Demand is not particularly complex and is often at the heart of arguments by those against roads in general. I suspect its impressive sounding name is designed to intimidate opponents and is presented as an indisputable fact. That said, it is used as it does have some merit, however it must be looked at in context - is the growth in traffic a result of economic growth, population growth? the increasing affordability of cars? And, if there was an increase in car usage is this outweighed by the environmental benefits of a nonstop motorway?, the economic benefits of improved transportation?

Should new roads result in a disproportionate increase in car usage during peak hours, road pricing could be introduced during those hours to discourage CBD commuters while maintaining the benefits of a motorway for freight and business traffic and the those making a weekend visit to granny in the northern suburbs.


adam73837 - I admire your persistence!!

[monotonehell]

The principle of Induced Demand is not particularly complex and is often at the heart of arguments by those against roads in general. I suspect its impressive sounding name is designed to intimidate opponents and is presented as an indisputable fact. That said, it is used as it does have some merit, however it must be looked at in context - is the growth in traffic a result of economic growth, population growth? the increasing affordability of cars? And, if there was an increase in car usage is this outweighed by the environmental benefits of a nonstop motorway?, the economic benefits of improved transportation?

Should new roads result in a disproportionate increase in car usage during peak hours, road pricing could be introduced during those hours to discourage CBD commuters while maintaining the benefits of a motorway for freight and business traffic and the those making a weekend visit to granny in the northern suburbs.

adam73837 - I admire your persistence!!

Well reasoned. Let's look at it in the context of Adelaide then shall we?

During peak periods (the times when people complain that the roads are at or above capacity) which arterial roads are 'full'? The answer is - all of them. Where do those roads go? The answer is - all directions. In light of that, in order to relive congestion where is the best place to run a freeway? Probably in no one corridor. The reason is that people do not go from a common point A to a common point B. Their trips are many and varied.

The main point that comes from the study of induced demand on freeways is that they aren't always the answer, and in most cases are actually a route to a larger problem, as well as negative flow on effects. In a sprawl like Adelaide people want to go in many different directions, therefore it makes more sense to spread the traffic load over as many roads as their are directions. During peak period there are a few common destinations, and a well patronised public transport system can help reduce the load by catering to those people.

That's not to say freeways don't play a positive role in a city. Just that the patterns of use don't always turn out to be what people envision them to be. We've had around 50 years of experience to learn from in the rest of the World. No need to repeat their mistakes because we don't ask the right questions.

[Aidan]

The principle of Induced Demand is not particularly complex and is often at the heart of arguments by those against roads in general. I suspect its impressive sounding name is designed to intimidate opponents

I hadn't realised the name sounded impressive. Can you think of a less impressive but still descriptive name for it?

and is presented as an indisputable fact.

Its existence is a fact. What is disputable is the amount.

That said, it is used as it does have some merit, however it must be looked at in context - is the growth in traffic a result of economic growth, population growth? the increasing affordability of cars?

Induced demand exists without any of these factors, although it can be hard to separate out the effects, especially with population growth. To see why, look at Mount Barker: the freeway (since the tunnels opened) has resulted in substantial rapid population growth, but if it hadn't happened there then it would happen somewhere else.

And, if there was an increase in car usage is this outweighed by the environmental benefits of a nonstop motorway?,

I can't think of any urban situation where this is the case.

the economic benefits of improved transportation?

Obviously this is something for cost benefit analysis, but it must be considered against alternative options. This is where the MATS Plan failed technically.

Should new roads result in a disproportionate increase in car usage during peak hours, road pricing could be introduced during those hours to discourage CBD commuters while maintaining the benefits of a motorway for freight and business traffic and the those making a weekend visit to granny in the northern suburbs.

True. But a new N-S motorway above ground can be ruled out completely, and the economic case does not yet justify constructing one below ground. Upgrading South Road (giving most of the benefits of a freeway) is a better strategy for now.

adam73837 - I admire your persistence!!

I don't think abandoning a thread when your points have been addressed and then coming back and acting like they haven't been counts as persistence!

[camaro68]

It amazes me how most responses to the north/south freeway are against it, I must in the presence of greatness as you all obviously know something that all the other countries/cites of the world don't. :wank:

Have you ever considered a job with the ACC, I reckon they’ll need a few draconian replacements sometime soon.