Starting this week I’m trying out a new feature: a midweek post rounding up some new articles on transport and urbanism. (Time for writing more substantive posts has been a bit tight lately.) The themes will be familiar to regular readers.

Let’s start with congestion pricing – a perennial topic of fascination for economists. Congestion pricing is mainly seen as a policy to improve the efficiency of road networks by “pricing in” the cost of delay that motorists impose on each other. But, based on London’s experience with a cordon charge, it may also improve road safety for all users. Charles Komanoff at Streetsblog NYC reports on some new data:

Evidence keeps mounting that congestion pricing can catalyze major reductions in traffic crashes. A year ago I reported on research that vehicle crashes in central London fell as much as 40 percent since the 2003 startup of London’s congestion charge. The same researchers are now expressing the safety dividend in terms of falling per-mile crash rates, and the figures are even more impressive.

The researchers — economists associated with the Management School at Lancaster University in northern England — compared crashes within and near the London charging zone against 20 other U.K. cities, before and after 2003. Their conclusion: Since the onset of congestion charging, crashes in central London fell at a faster rate than the decrease in traffic volumes. As important as the reduction in traffic has been for safety, at least as much improvement is due to the lower crash frequency per mile driven.

In short, driving in the London charging zone isn’t just smoother and more predictable, it’s safer. And safer for cyclists as well as drivers, with the number of people on bikes expanding considerably as car volumes have fallen.

And on that note, a reminder that the best way to improve the safety of cycling is to increase the number of cyclists on the road (or better yet, cycleway):

But that’s the big smoke. It couldn’t happen here, in small, rural New Zealand, could it?

Maybe not. “Town Proper”, an urban design and transport blog, points out that we often get it wrong when thinking about the rural-urban balance in our society. (Riffing off a post I wrote a while back.) We tend to “mistake want as demand“:

Purportedly New Zealanders value open space, ball games and big houses. That does not hold up to our litmus test though. As reported above, most of New Zealanders have chosen to forgo big houses, large and open (private) spaces in exchange for the vitality of a denser area.

It is not like there is a critical shortage of open land in New Zealand – you can easily buy a dozen or so hectares with a big house for below Auckland’s average house price. Rather, people do not want to live there.

When you have multiple wants, you must make a choice as to the prioritization of your wants. It seems that while New Zealanders might want the rural lifestyle they have decided to choose the urban lifestyle over it. This is where so many commentators make a mistake, they confuse wants for demand. Demand is when you not only have the want for something, but also the ability (and the willingness to expend that ability) to obtain it.

There is little demand to live in rural areas (only 20% of Kiwis live in rural areas, and most of them in “rural centers”), why? I propose that generally Kiwis value the advantages of an urban area above the disadvantages.

Indeed. When planning cities, it’s important to take into account people’s needs and the real choices that they face, not just a hypothetical idealised notion of how people should live.

Which brings us to California. The land of technological disruption is steadfastly refusing to allow its housing market to change. And so demand for urban space – particularly the dense, connected urban space of San Francisco – is colliding with scarcity. TechCrunch’s Kim-Mai Cutler puts the issue in historical perspective: “A Long Game“:

I believe we’re hitting another major juncture, although I don’t know when it will deteriorate to the point that it forces real reform. California’s fragmented, post-war suburban model, which was created for a more even wage distribution in a mass industrial economy, is clearly becoming more dysfunctional by the year for a knowledge-and-services economy with a wider level of income stratification.

Not only are we not building enough housing overall, we have scarce sources of funding for supporting those on the lower-earning ends of a rapidly widening income spectrum. So we end up politicizing and extracting funds out of new construction even though we are 40 years deep into a largely self-imposed housing shortage.

There are a couple of disturbing trends showing up in the data. If you look across the state’s workforce, Californians born in 1990 are on average spending 50 percent of their income on housing. That’s way above the 30-percent-of-income level that is generally considered to be the threshold of whether housing is affordable or not in public policy conversations.


Then, if you look at working-class segments, commutes are rapidly rising for the lower-income workers in the region:

This is troubling because commute time is one of the strongest predictive factors in determining a child’s chances of climbing from the lowest income quintile to the highest-earning one. That morning and evening time between parents and children that is taken up by commuting is invaluable for bonding and child development.

The data on the length of commutes is incredibly important. As I found when I looked at Auckland’s commuting patterns, lower-income households can access lower rents by living further out, but the gains tend to be erased by added commuting costs. If there are also additional social costs from long commutes, it reinforces the importance of giving people the option to live closer in.

Back in New Zealand, and on a very different note, Peter H from Hamilton Urban Blog takes a look at street trees in Frankton Central, Hamilton. This kind of micro-scale analysis of urban places can be incredibly valuable in illuminating what’s good about a place and what can get better.

The following map shows existing street trees in Frankton Central. Viewed in terms of ecological function, Frankton Central’s street trees represent an incomplete system with gaps. Although the mapping of street trees points towards a substantial number of trees in the Frankton, these have only limited impact on the experience of green in the wider area.

Frankton central TreesThere are a number of streets with sporadic tree canopies as seen in the map above. The green network created by street trees varies widely in quality. Both ends of Commerce St have thriving street tree corridors that give those areas a distinct character. The interesting trees contribute an artistic flair to the retail part of Commerce St.

There are new plantings throughout the town, particularly in south-eastern streets, but the ecological, architectural, and urban quality benefits of these trees are not yet evident. The current town green network has gaps and there are sections of the Frankton that do not have any real trees.

It would be interesting to see some similar maps for different parts of Auckland. I wonder if Auckland Transport maintains a database of street trees in its road reserves?

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  1. Indeed. When planning cities, it’s important to take into account people’s needs and the real choices that they face, not just a hypothetical idealised notion of how people should live.

    Exactly, well said. Letting people make real choices about where they want to live is at the core of making a great city.

    If there are also additional social costs from long commutes, it reinforces the importance of giving people the option to live closer in.

    The key word here is “option”, it must be a choice that can be freely made. Enforcing a hypothetical idealised notion of what is best will deny choices and increase costs.

  2. The safety observation for road pricing is an interesting one. Predictable smooth travel probably means peope are less likely to get frustrated and make poor desicions. Imagine if everywhere people drove it was like that. I can imagine that could lead to a much safer and more courteous driving culture.

    1. Yes. Or here’s an alternative explanation: the “bad” drivers are the ones who are most readily priced off the roads.

      I think a combination of both effects is most probable.

  3. Is that a new trend for younger people to spend a higher percentage of their income on housing, or is it just continuing an existing pattern – i.e. if you did the same analysis with data from 20 or 50 years ago, would you get the same result? Seems to mirror my parents in the ’60s – got married in their early ’20s, had 6 kids, bought a house, scrimped and saved, income increased with age and experience, mortgage payments stayed the same, by mid-40s mortgage paid off, Bob’s your uncle…

    1. If you look at the graph it clearly shows that people born earlier spent significantly less ofther income on housing when they were 20 or 30 that those born around 1990.

      Basically the boomers in San Fran have rigged the market, the same way that they are in Auckland.

      1. 55% vs 45% at age 20, 45% vs 40% at age 25, should both be about 35% at age 30 (if you extrapolate the yellow line).

        Wonder what the real causes are for the sudden change in commuting distance for sub $15k earners since 2010?

  4. I always thought the greatest tragedy in Auckland was the removal of blanket tree protection in 2012. The results have been disgusting.

    It’s one of the reasons I support apartment towers. Going up, not out, means more greenspace even while you increase population density and get all those agglomeration benefits. Terraced housing = tree murder. Infill housing = tree murder. Perhaps we could have a new planning rule for every x m^2 of floor space you need to plant y trees.

    Also, while it’s intuitive that a sprawling city means longer commute times, it isn’t absolute. A small, dense city where walking is the only travel option would have longer commutes than a sprawling city with high frequency high speed rail lines. We could have both easily enough; a sprawling Auckland built around a 20 train per hour network with 30 second dwell times, served by frequent (5 minute) minibuses to and from the stations.

    1. I think it is more like:
      – apartments towers = more density than townhouses
      – townhouses = more density than freestanding houses

      Where does this idea that townhouses and trees can’t coexist come from?

      1. Basic geometry. Townhouses don’t have backyards. Suburban houses do; apartments don’t, but apartments enable economies of scale to build parks nearby, where you put trees.

        1. Townhouses do usually have backyards (and some suburban houses don’t). Even my apartment building has a backyard.

          You’re concept of tree murder is a little off. I’ve got a large site with one house on it with one significant tree and some scrubby crap. In about a year when I’ve put four terraced houses on it, it will have planted seven more signficant trees ,and a bunch of other landscaping, so that each house has a significant specimen in the both the front and back yards.

          Not sure how octupling the number of trees counts as murder.

          1. I commend you for planting 2 trees per townhouse, how large will these trees grow? One of the problems with trees is the wrong tree planted in the wrong place, where they can end up causing damage to paths and gutters, especially on smaller sites where height or width cause problems with shading.

            I’m on a larger site, but have had to remove most of my trees because they were in the wrong location, planted too close to buildings and had grown too large (one toppled on to the neighbour’s house). Replaced with natives on the boundaries away from the buildings, and lots of firewood for the next few winters.:-)

          2. I’ll leave that to the architect to pick the right species, but trees are part of the design of the houses (privacy, shade, separation etc).

            I know what you mean though, my folks used to have two enormous Norfolk pines, one in the wrong place. Now they have one in the right place and a big pile of firewood.

          3. There’s some remarkable anthropocentric prejudice here. “Right place” for a tree? The right place is where it grows. “Damaging gutters and paths”? Immediately privileging artificial constructions over natural ones; the tree is a far more complex creation than your concrete path.

            In my view, the focus should be on the natural elements

          4. A Norfolk Pine is an entirely artificial construction, given that we don’t live in Norfolk island… its not less artificial to lay a sapling than to lay a pipe.

        2. That is just fundamentally untrue. You’ve also forgotten that the townhouses occupy less land, leaving more forest intact.

          1. Not talking about forests, talking about urban trees. Look at Paris on a map. Look at Auckland on a map. Whhich has more urban trees

        3. OK, I guess you’re talking about Auckland here.

          In Auckland we have these silly things called “Townhouses”. They often come in groups of up to a dozen on a large lot, have a body cooperate, and indeed no private backyard. Some developments have some common space, and that often comes with trees.

          In Europe we have townhouses. They usually sit on small freehold sections, come with a backyard, and the more recent ones usually have some setback in the front for parking.

          The latter are extremely rare in Auckland. Basically this is the same as what you find in tramway-era suburbs, but on more narrow sections and without metres of space between neighbouring houses. One example regularly popping up here are the houses called the “six sisters” in Ponsonby. They sit on small sections (under 200m²) and they do have trees in their backyard.

          1. Toronto has a lot of townhouses (European definition), as well as semis and detached houses on narrow sections. Little to no space wasted at the sides allows more space at the back. Most have setbacks at the front too, with some households using the space for parking and others landscaping it. I saw some gorgeous trees in those front yards.

    2. I like trees a lot, and oppose cutting down old native trees. However, I’m not in favour of blanket tree protection. The problem is that preventing people from cutting down trees will also discourage them from planting new trees in the first place. Over time, this will lead to a city with less trees, not more trees.

      For example, if somebody knows that planting a tree in their backyard would prevent them from redeveloping the lot in 30 years time, they simply won’t do it. The result is that instead of having a tree there for 30 years, you don’t have a tree at all. Sub-optimal.

      However, I do think that it’s worth looking at other policy mechanisms to encourage people to plant more trees. Particularly on streets, where AT can simply plant and maintain them itself, and in big paved expanses such as parking lots.

      1. That argument sounds remarkably like the “we don’t need a minimum wage because it will just prevent people hiring people in the first place” argument to me.

        Anyway, even if you were right, if we looked at the # of trees in Auckland when the protection ended, that was enough if not one of them had been cut down.

        1. Theres a fundamental difference. The minimum wage seeks to regulate trade between people where there is arguably a power imbalance.

          Regulations on trees seek to change the relative value that the same individual places on trees compared to, say, floor space. Presumably such regulations would be motivated by the presence of externalities.

          So I wouldn’t say that policy arguments with regards to urban trees are particularly relevant to discussions of minimum wage.

          1. Both rely on the philosophy that distorting the market via regulation changes behaviour (not planting trees, not hiring 16yos) do they not?

            Maybe I’m stupid (probably) but if the presence of a minimum wage doesn’t reduce willingness to hire, why would the presence of tree protection reduce willingness to plant?

          2. A minimum wage is not a good analogy for blanket tree protection. Minimum wages set standards for contracts but don’t restrict employers’ ability to fire or workers’ ability to quit. So they would be more like a rule that required people to only plant native trees, but allowed them to cut them down if needed.

            Basically, minimum wages preserve labour market flexibility. If a firm experiences a drop in sales, it is still able to cut costs by laying off staff. This is obviously traumatic for the people who get fired, but there are benefits for the remaining staff, as the risk of *them* losing their jobs due to business failure is reduced. The appropriate way to address this “fairness” issue, in my view, is to have a social welfare system that provides good support for unemployed people, and an education system that enables people to gain new skills throughout their life. An alternative policy – prevent businesses from firing staff – might look superficially appealing but would carry the risk of unintended consequences.

            Getting back to tree protection, I would encourage you to ask two important questions:
            * Is there a risk of unintended consequences from the policy, e.g. people planting less trees to ensure that they aren’t limited in development options in the future?
            * Is this policy really the most efficient way of achieving the aim of a greener city, or would it be better to do something different, like having council plant street trees itself?

          3. I live in a suburb where people have large sections and lots of big trees. For weeks just before blanket tree protection came in there were dozens of chainsaws going as people got rid of anything they thought might need to be pruned or removed in the next 20 years! Wholesale slaughter because someone thought a rule would be a good idea. After the rule we didnt plant any natives or even exotics we thought we might not be able to remove. If you are happy with privet and weeping willows everywhere then by all means introduce blanket tree protection.

          4. * Is there a risk of unintended consequences from the policy, e.g. people planting less trees to ensure that they aren’t limited in development options in the future?
            * Is this policy really the most efficient way of achieving the aim of a greener city, or would it be better to do something different, like having council plant street trees itself?

            There is always a risk because most people are venal. If people value a few dollars from subdivision in the future over beautiful living organisms, however, it begs the question: do these people deserve the rights and responsibilities they are given?

            Street trees can never truly green a city unless the streets are huge, which goes against liveable neighbourhoods.

            A better approach would be:
            1. Restore blanket tree protection *without* warning to avoid “windfall gains”
            2. Hire a lot more resource management enforcement officers, who could use aerial surveillance photos to identify potential cutting
            3. In cases of cutting, seize the land and buildings (illegal fishing = your car gets seized)

          5. You put up a good guise of moral righteousness, Early, but you can’t tell me you aren’t laughing as you type that sort stuff. Nice trolling but it is getting pretty outlandish now.

          6. I would have thought the best way to ensure a good number of trees in the suburbs would be minimum requirements for permeable surface, which as far as I’m aware already exist. Some people would choose trees, others lawns or gardens; on the law of averages we would end up with a consistent amount of trees.

            As mfwic and others rightly point out the tree rules just result in perverse outcomes.

          7. Made me laugh too Early but in case you were serious they let you prune 10% each year and if you pruned in spring you could shock the tree into not growing that year so over a series of years you could slowly get rid of a tree you didnt want. On the other hand my neighbour pruned the bottom 10% and the rest of the tree just fell over!

          8. Early Commuter would also appoint commissars to prevent any inappropriate use of pruning implements to harm trees. Stasi-style networks of informants in every neighbourhood, aerial drone strikes against people having chainsaw-related phone conversations, etc.

            This is starting to sound like Animal Farm for gardens. Legs bad, roots good!

      2. Thanks Peter for posting the Frankton tree map.
        Here in Hamilton there’s a fellow acting a bit like a Oncer-ler family member with a very strong dislike to some ones right type of tree planted a few decades ago, which are now the wrong type of tree. In the CBD we are now close to having a quarter of the mature trees removed in the past 5 years.

        It now looks like the Super-Axe-Hacker is about to be moved to Frankton
        Frankton neighbourhood Plan – “To start immediately … Commerce Street …replacing the street trees”

  5. “It would be interesting to see some similar maps for different parts of Auckland. I wonder if Auckland Transport maintains a database of street trees in its road reserves?”

    We have access to some of the Council GIS data at the University, including their tree register (which, itself, includes street-side trees from AT). I had a quick look just now and there’s a lot of them. Over 200,000 in total. Though the coverage is far from uniform. The old Auckland, Waitakere and North Shore city areas seem to be comprehensively audited. Other areas less so.

    I don’t think there should be any problems in making and posting some maps from this data, but sharing the data itself would likely be prohibited. I’m short on time today, but can double check with our library staff tomorrow, or Monday.

  6. “It is not like there is a critical shortage of open land in New Zealand – you can easily buy a dozen or so hectares with a big house for below Auckland’s average house price. Rather, people do not want to live there”

    No, people can’t live there because there is no employment.

    1. Yes, that’s the point of the article. People value proximity to large, diverse labour markets. So rather than trying to push water uphill, and disperse people to places where they don’t really want to be, it’s better to focus on making cities work better.

      1. There’s a proverb I once heard: a politician follows the people, a statesman leads the people.

        You can’t just let “nature take its course”. You have to regulate, because people have short-term, selfish fixations.

        1. In the days before opinion polls we had statesmen. Politicians had to say what they stood for. Many got it wrong and were thrown out, but a few guessed the public mood through good luck- they were then labelled ‘statesmen’.

  7. Anyway, I want to add a comment about “natives.” The term is an artificial construct; plant seeds have been traversing the world on the wind for millions of years. New Zealand was once part of a larger megacontinent; what we call “native” is merely the lucky few that hitched a ride when we broke away (which but for fate might have included the Norfolk Pine).

    As long as we protect natives, we don’t need to think of them as the only worthy tree. An oak is far more noble than most natives (but it pales before the kauri). Olive trees are not native, yet old-growth olives are some of the most charming things you will ever see.

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