Stephen Woodcock, “The maths of congestion – springs, strings and traffic jams“, Phys.org (via my dad):
How can one report filed with the NSW Major Project register predict 20,000 fewer cars per day on a section of Parramatta Road, while other reports within the Roads and Maritime Services state that no significant reductions are likely to be seen?
It is very easy to chalk up some of these differences either to wildly overoptimistic developers potentially misleading themselves and others to get a project approved. Similarly, it is sometimes alleged that feasibility studies might be influenced by political biases or pre-established views on the merits of roads or public transport schemes.
While these factors may well influence some decision making, one thing that is often missed in the reporting of such studies is the sheer complexity associated with analysing such networks. Assuming all roads are connected, the behaviour of a whole network can be hyper-sensitive to how individual parts, even seemingly minor ones, function.A poor estimate of traffic flow in one section of a network can lead to hugely different behaviour across the whole system. Furthermore, even the simplest networks can have the potential to function in some extremely surprising and often counter-intuitive ways.
It is very easy to believe that if a traveller is offered the choice of two routes for a journey that the addition of a third choice should not worsen his/her travel time. If the new route is slower, the traveller could simply ignore the new route and make the same choice as before.
As the German mathematician Dietrich Braess pointed out, this is not always the case. Increasing the capacity of a network can, perhaps surprisingly, decrease the efficiency of journeys around it even without increasing the number of trips made, as was pointed out in a recent article…
This paradox is not simply a mathematical quirk or one which can be neglected by network analysts. There are a number of examples where removing roads – rather than building news ones – has improved transport networks.
Probably the most famous example of this comes from South Korea. When the motorway network around Seoul was reworked to remove some of the 1960s-built roadways, the the result was significantly reduced transit times throughout the city. This was not because of fewer journeys through the city, rather a more efficient distribution of cars across the remaining network.
Similar phenomena have been observed during road closures in New York City in the United States and in Stuttgart in Germany.
The Economist, “Technology in New Zealand: Kiwis as guinea pigs“:
IN MEDICINE, trials are conducted on guinea pigs, rats, mice and rabbits. In digital businesses, tests are performed on New Zealanders. Their country is proving the perfect location for software firms, social networks and app developers discreetly to try out and refine their products…
New Zealand’s relative isolation means that if a product needs to be modified significantly to fix faults or make it more appealing to consumers, word of its teething troubles is less likely to spread, thereby discouraging customers elsewhere from trying the improved version. If a firm finds that a particular product, or a new feature added to an existing one, is a resounding flop in New Zealand, it can quietly be dropped without having much effect on the company’s overall reputation.
Simon Vincent, “The Ride to Wigan Pier – a story of kids, bikes, and beer“, Cycle Action Auckland:
Cycling along the cut was always a joy. The path was not smooth; its rough surface allowed us to jump and practice our wheelies. It did, however, have its dangers. The overgrown brambles narrowed the path and the thought of ending up in the cut was not a pleasant one. Water quality was not something we thought of in those days, but we did worry that lurking in those murky depths lay piscine danger – a giant pike, known as Big Bess, that had snapped many an angler’s line hunted here. And, more improbably, the story that a unscrupulous pet shop owner had discarded his stock of piranha in the canal was doing the rounds at school
We rode and we rode. We rode so far the accents along the tow path changed again and again. We called out “Any luck?” to those fishing on the banks, and bartered with bargies – we would open the locks for them in exchange for our shandy money.
A bicycle was our passport to the wider world and we loved the freedom it gave us.
Joseph Stromburg, “Highways gutted American cities. So why did they build them?” Vox:
So why did cities help build the expressways that would so profoundly decimate them? The answer involves a mix of self-interested industry groups, design choices made by people far away, a lack of municipal foresight, and outright institutional racism.
“There was an immense amount of funding that would go to local governments for building freeways, but they had little to no influence over where they’d go,” says Joseph DiMento, a law professor who co-wrote Changing Lanes: Visions and Histories of Urban Freeways. “There was also a racially motivated desire to eliminate what people called ‘urban blight.’ The funds were seen as a way to fix the urban core by replacing blight with freeways.”
This is also notable, and likely to apply to New Zealand as well:
Even though gas taxes have never fully paid for highways — a recent Public Interest Research Group report found they’ve covered between 43 and 74 percent of costs through the interstate system’s history — the widespread perception that highways and freeways are somehow self-funding has stuck around.
Simon Bush-King, “From polder to pavlova paradise“, Architecture Now (via Brendon Harre):
The Dutch experience is far removed from New Zealand. Historically, in the Netherlands most land was owned, developed and sold by national or local governments. Housing was developed at scale by private developers and few people were able to build an individual house. Housing was however, generally of a high standard and affordable. Over the last 20 years, the Dutch have introduced a greater flexibility and individual focus to the housing industry that is more relevant to the current context of New Zealand. While introducing market-led reforms, they have retained the benefits associated with building at scale, articulating a clear vision and involving all affected parties. In short, the Dutch plan – in the original sense of the word; opportunities in greenfield and brownfield sites are identified, development options are tested and the affected community is involved early in the process. Rather than lobbing grenades from the sidelines, all parties have a seat at the table. It is a process that invites certainty for communities, developers and the financial institutions involved. Public Private Partnerships are the norm. Over the years this approach has produced a number of interestingly diverse examples. Those that follow include the exciting and well-known as well as projects destined to be comfortable places in which to raise a family, rather than grab the spotlight…
Het Funen
Funen, Amsterdam, a development that combines living and working in high city-centre densities with sufficient green space on ‘Het Funen’, a former industrial zone on the edge of Amsterdam’s city centre. It is a concept that incorporates the qualities of diverse typologies: the construction of perimeter blocks along two sides, with a novel interpretation of the ‘garden city’ model to their rear.
At a different scale altogether, ‘Het Funen’ – or Hidden Delights – consists of 500 dwellings set in open space on what was a former parking lot for towed cars in east Amsterdam. A masterplan by Frits van Dongen established a perimeter block around the right angle of a difficult corner site that acts as a barrier to the busy railway line adjacent. A loose grid of 16 housing blocks is laid out within the triangle with a diversity of typologies: live-work units, maisonettes, penthouses, seniors housing, studios and houses specifically design for the disabled. There is a mix of individually owned and rental accommodation. The ground floor of the perimeter block contains commercial space. In this instance a single company – IBC Vastgoed – undertook the entire development. Usually it would be instigated by the city.
The Economist, “London skyscrapers: The ascent of the city“:
These protected views help to explain why tall buildings are rising in such a dispersed pattern. The Shard will not get neighbours anytime soon, as it is wedged between two viewing corridors. In the City, towers are scattered instead of crowding around transport hubs, as economic theory might predict. Their odd designs—described by nicknames such as the Gherkin, the Walkie Talkie and the Cheesegrater—are in some cases a means of avoiding imposing on St Paul’s. Only at Canary Wharf, which is too far east to spoil many views, do cuboid skyscrapers rub together in the way they do in other big cities.
The other reason London’s tall buildings are so oddly spread is local democracy. In the conservative borough of Westminster, the council resists almost all new tall buildings; despite soaring rents, no new skyscrapers have been built there since the 1960s. In the corporatist City, expensive architecture is prized. Almost anything goes in poor Labour-run authorities such as Lambeth, Southwark and Tower Hamlets.
Tom Vanderbilt, “Five myths about traffic“, Washington Post:
2. Faster roads are more efficient roads.
Speaking of efficiency, common sense says that when drivers are humming along at or even above the speed limit, highways are performing at their best. The German autobahn, with its (shrinking) speed-limit-free zones, is often offered as a shining example. It must be those slower drivers who are holding things up!
But as good as fast-moving roads might be for the individual driver, they are not the best for the most drivers. As data gleaned from in-pavement “loop detectors” on Washington state highways showed, those highways were able to achieve “maximum throughput” — pushing the most cars through one segment of road in a given time — at speeds that were roughly 80 percent of the posted speed limit of 60 mph. Why? At higher speeds, drivers need to allow more “headway” between vehicles, meaning more space is required per vehicle. And faster-moving traffic tends to break down more quickly, with more severe “shock waves”; it takes a lot longer to recover from a traffic jam than to get into one. I have been told, anecdotally, by traffic engineers that the left-hand “passing lane” can become congested first. (I’ll leave it to you to decide if karmic justice is at work there.)
Ramez Naam, “Renewables are disruptive to coal and gas“, Marginal Revolution:
Wind and solar compensate for each other’s variability, with solar providing power during the day, and wind primarily at dusk, dawn, and night.
Energy storage is also reaching disruptive prices at utility scale. The Tesla battery is cheap enough to replace natural gas ‘peaker’ plants. And much cheaper energy storage is on the way.
Renewable prices are not static, and generally head only in one direction: Down. Cost reductions are driven primarily by the learning curve. Solar and wind power prices improve reasonably predictably following a power law. Every doubling of cumulative solar production drives module prices down by 20%. Similar phenomena are observed in numerous manufactured goods and industrial activities, dating back to the Ford Model T. Subsidies are a clumsy policy (I’d prefer a tax on carbon) but they’ve scaled deployment, which in turn has dropped present and future costs.
Paul Krugman, “Preliminary notes on inequality and urbanism“, New York Times:
[W]hen it comes to things that make urban life better or worse, there is absolutely no reason to have faith in the invisible hand of the market. External economies are everywhere in an urban environment. After all, external economies — the perceived payoff to being near other people engaged in activities that generate positive spillovers — is the reason cities exist in the first place. And this in turn means that market values can very easily produce destructive incentives. When, say, a bank branch takes over the space formerly occupied by a beloved neighborhood shop, everyone may be maximizing returns, yet the disappearance of that shop may lead to a decline in foot traffic, contribute to the exodus of a few families and their replacement by young bankers who are never home, and so on in a way that reduces the whole neighborhood’s attractiveness.
On the other hand, however, an influx of well-paid yuppies can help support the essential infrastructure of hipster coffee shops (you can never have too many hipster coffee shops), ethnic restaurants, and dry cleaners, and help make the neighborhood better for everyone.
Gordon Campbell, “Castles in the Square“, Werewolf:
In sum, almost every major city and tourism centre in New Zealand is – simultaneously – building or extending convention centres, and is taking significant risks and investments in public money ( and public land) in the process. All these complexes are targeting much the same basic audience : the domestic and international conference markets. The economic rationale for these projects is based on the spending that the centres are being hoped to generate from (a) the hotels that will accommodate the delegates (b) the bars and restaurants that will serve them and (c) the retail outlets in which they will spend a remainder of their money.
To date, there has little or no analysis of what the net national benefit would be – if any – to New Zealand from these ventures. Constantly, the facilities will be competing with centres offshore for hosting rights to a limited number of major international conferences. Domestically, one region’s gain will be another region’s loss.
The infrastructure investments needed to support the expansion of the private car ownership paradigm. H/T @Carsharing pic.twitter.com/gwYEqTk10v
— Chris Bruntlett (@modacitylife) May 28, 2015
Processing...
Peter the Netherlands historically used compulsory acquisition as a tool for these housing projects, less so now and Germany when local governments consider property prices do not match underlying fundamentals also use the power of compulsory acquisition.
There is a discussion of “Property law: compuslory acquisition” by the FT that might help give some light on the subject.
http://www.ft.com/intl/cms/s/0/3c732968-9bf1-11e4-a6b6-00144feabdc0.html
In NZ we are not far off using compulsory acquisition for housing. The government is using excess Crown land for housing -500 hectares in Auckland.
A planned approach where the government acquired land in locations where they can integrate the public sphere -roads, PT, public services -schools, healthcare etc with the private sphere -housing, commercial etc would seem the logical next step.
I have just spent most of last month based in Vathorst-Amersfoort, very much a architects and town planners play ground,
This is how they explain the design priorities.
The Dutch government sets priorities in dealing with population growth, which are based on VINEX-paper introduced in 1993, which has four main purposes (1) trying to enlarge existing shopping and service areas, so they are used more frequently and their ‘efficiency’ will rise. Thereby (2) diminishing the pressure for young people to move outside the Dutch cities, and (3) protect the remaining ‘open space’ in the Dutch landscape by building programs close to city centre. These new close-to-city-districts (4) make distances attractive for walking or biking.
Thanks Brendon – keep the excellent link suggestions coming! Unfortunately, I don’t have access to the FT, but this article sounds quite interesting. Does it discuss NZ in particular?
My understanding is that NZ has a few legal barriers to compulsory acquisition for the purpose of housing/commercial development. Unlike the US, where governments’ eminent domain powers are quite broad (dangerously broad, in my view), the Public Works Act sets more limits on what governments can do with compulsorily acquired land.
In particular, if a government acquired land for infrastructure and later decided to release it back to the market, it may be compelled to offer it back to the original owner, at the original price (plus inflation). I believe this can all get quite legally difficult pretty quick…
Peter check this link out http://www.teara.govt.nz/en/land-ownership/page-5. NZ’s longest serving government 1891 to 1912 land policy was based on land taxes and purchases of large blocks of land for sub-division and sale. Some of those purchases being via compulsory purchase. So NZ has a history of using government policy to eliminate land banking. This created the eco-system of small family run farms that became the backbone of our economy and political system for many years.
I do not know the current laws regarding government compulsory acquisition of land for housing. But surely it is only a small step from using excess Crown land for housing to acquiring new Crown land in correct amounts and locations for the public and private development of said land.
The FT link(not paywalled) was about the UK not NZ. It discussed how much compensation/payment a land owner could expect when their land was compulsorily acquired. In my discussions with farmers they are not against compulsory acquisition as they are well compensated -one farmer telling me they recieved 60% over the usual rural value and this easily allows them to replace the lost farmland with equal or better farmland.
“Even though gas taxes have never fully paid for highways — a recent Public Interest Research Group report found they’ve covered between 43 and 74 percent of costs through the interstate system’s history — the widespread perception that highways and freeways are somehow self-funding has stuck around”.
Lets think about this statement further. I humbly suggest that footpaths, and cycleways, and social welfare are even less self funding. The statement above is pretty much irrelevant, but will pander to the anti-car evangelists.
How about bus and train tracks that are even more heavily subsidized?
Just keeping perspective balanced.
What don’t you understand? No one claims there are no subsidies for footpaths and PT, but people do believe, wrongly, there are none for driving amenity. As is clearly stated above. Your constant attempts to paint the road industry as some sort of noble but misunderstood victim is sadly wide of the mark.
Just be grateful our taxes pay you to draw motorways we don’t want all day.
Those costs are purely the physical costs of the infrastructure as well, and take no account of the additional hidden costs such as due to congestion and negative health effects (not to mention the huge opportunity costs of dropping billions on unneeded roads) which we all end up paying for as well.
Nobody, I repeat – nobody, but you, argues with any conviction that because all those other things are not “self-funded” either its relevant to the roads lobby.
Your comparison and straw man argument about the anti-car brigade is bogus, utterly meaningless and crap.
The argument is not whether the “self-funding road” kettle is less black than the all the other pots in the kitchen.
Its quite simply making the point, that the “self-funding roads” lobby, as you yourself indicate this with your response – doesn’t even see itself as even belonging in the kitchen, let alone being of exactly the same kind as those other “state funded” things. A casual glance (or a modicum of internet research) shows that it is clearly wrong.
The US Interstate system was very much paid for by the US government [US taxpayers], and was sold to Congress partly on the basis that they had to be funded by the US government because a national road network was needed.
They were intended to be used at times by the US Armed forces, to assist them with future National Emergencies or wars (civil or foreign invasion).
This was the post WWII and General [then President] Dwight D Eisenhower had seen how the then German Autobahn system worked well for Germany’s armed forces during WWII and also for the Allies during and post WWII – so there was a recent real life example to hand.
It was of course, partially paid for by a Federal “Gas tax”, but this tax has never kept pace with either the original costs needed to build (or now expand) the system, and even maintain it.
Inflation has further reduced what percentage that, that tax did/does contribute so its no more “self funding” now than it ever was when the first lot of money was handed over.
I’ve been reading a bit about transport pricing lately. One thing that all economists who’ve looked seriously at the issue is that a failure to price roads properly – which means, basically, to charge people for the delays that they impose on others when using busy roads – has spillover effects onto pricing for public transport. Essentially, if roads aren’t priced properly, it’s necessary to give a higher subsidy to public transport to encourage people to travel less on highly congested roads.
In this respect, public transport subsidies should more properly be seen as subsidies for the remaining drivers. If we didn’t subsidise PT, car commutes would be more painful.
Furthermore, as highlighted in the Vox article on the construction of the US interstate system, when the system started getting built, it was a subsidised – i.e. not tolled – transport mode that was competing with urban public transport systems that were recovering all of their operating costs. (Albeit not always making enough money to make capital investments.) The original sin of transport subsidies, in other words, was the construction of non-tolled highways.
I watched a youtube doco recently on americas crumbling infrastructure, basically how they are struggling to maintain the interstate and bridge failures are an ever increasing likliehood.
If you take into account the billions of dollars of public land that is used for roads (especially in Auckland), you may find roads are subsidised more than any other form of transport. How much is the land under Fanshawe street worth for example? Imagine if we charged every user of Fanshawe street the true cost of the land they are using!
Sydney Centre City should go car-free with Light Rail, hear, hear. So should Auckland [and CRL]:
http://blogs.crikey.com.au/theurbanist/2015/05/27/should-cars-be-banned-from-sydneys-cbd/
And you guys wonder why you’re called car haters…
I don’t wonder at all. I value my cars (yes I own two of them); I just know when and where to use them. Also they’re just tools; they don’t have feelings, I don’t worry about upsetting them, and nor do I give over my entire identity to them.
Didn’t say you hated them Pat, but that with all the negative banging on about them, hardly a surprise you’re regarded as such.
Haters gonna hate; I don’t lose any sleep over silly name calling.
The fact remains that the best, most success cities in the world are reversing last century’s car-centric policies, particularly in pedestrian and Transit rich downtowns. I am ambitious for Auckland, it is important for our prosperity and wellbeing that we don’t stay tied to tired old patterns:
http://www.theguardian.com/cities/2015/apr/28/end-of-the-car-age-how-cities-outgrew-the-automobile
This week, I posted three articles and one tweet that discussed cars or roads.
The first article, written by a mathematician, discussed a well-known physical phenomenon – Braess’s Paradox – which has important practical implications for managing road networks. Essentially, it means that some of the projects that “just make sense” actually don’t.
The second article, written by a journalist, discussed the history of the US interstate system, and, in particular, how it came to be subsidised by federal tax dollars. That’s just part of the historical record.
The third article, written by a journalist, discussed why some of the obvious “fixes” for traffic congestion may in fact make matters worse. For example, it observed another physical fact – that free-flowing traffic does not maximise the efficiency of the road network.
The tweet, posted by a bicycle activist, made a geometric observation – that less space is required to move people by public transport than by car. Again, simple physics at work.
In my view, this doesn’t amount to “negative banging on” about cars. It’s all very factual. We don’t have a bias against cars – we have a thoroughly rational bias towards facts and evidence. Please stop confusing those two things.
Thanks Peter. All contributing to what makes studying transport so interesting. The worked examples of Braess’ paradox look contrived, but as you say, there is real experience of it happening. The same phenomena occurs in competition between public transport and car travel – particularly if the pt is on a separate right of way – a Nash equilibrium occurs where the cost of travel is the same by both modes (including walking and waiting time etc) and improving the road can make both modes worse. (It doesn’t in the case where road is so much faster that no-one uses public transport by choice. This may still be the case for some Auckland trips but is becoming less so). The 80% of the speed limit you quote for maximum flow is a typical figure – if you assume the universal law of traffic follows a BPR function, that implies that maximum flow occurs at 75% of free flow. This is the economic optimum as well as the most efficient utilisation of the road. Ideally the charge for using the road should be set (varied) to ensure maximum flow and road capacity should only be added if the cost of new capacity is less than the revenue being received from the charges. Current charges (fuel tax) are far too low to prevent congestion and also too low to fund increases in road capacity. Auckland motorways are being built by cross subsidy from other road users.
Yes we can see the Nash equilibrium most clearly in work between the Northern Busway and SH1 between the city and the Shore; the attractiveness of the bus service essentially sets the speed of the adjacent highway at the peaks. Surely the most cost efficient way to improve effectiveness of the road would be to continue to increase the speed, frequency and reach[especially] of the bus services on this route. Extending the busway both north and on road priority for buses south through the city to the University, Hospital, Newmarket and perhaps beyond, and the connection with other improving services, especially the rest of the Rapid Transit Network. Happily some of this is coming in the North Shore New Network and, perhaps critically, fare integration which will practically make feeder bus trip free.
‘going forward’ as politicians like to say: http://www.citylab.com/housing/2014/05/what-millennials-wantand-why-cities-are-right-pay-them-so-much-attention/9032/
‘The key characteristics seem to be walkability, good schools and parks, and the availability of multiple transportation options.’
And here’s the kind of pay-off in place value that reducing vehicle domination of the public realm can do:
http://londonist.com/2015/05/are-these-londons-most-exciting-future-public-spaces.php
If your gut told you there is something fundamentally wrong with Braess’s Paradox then you were right and here is why.
1/ Note the diagram shows four links set out in symmetry to give the same delay before the new road and to ensure that after the new road the diagonal routes present a choice of a highly fixed delay (105 each regardless of volume) or a highly volume dependent delay (in this case 1 minute for each vehicle in total).
2/ The addition of the new link can then trigger a calculation of delay based on the volume dependent links that is higher than before.
3/ Every specification I have seen the fixed is always slightly higher than the result of all traffic using the vehicle dependent delay route.
4/ Hey presto the new link results in higher delay.
Thanks. That confirmed my gut feeling about the paradox