Snap out of the Walter Mitty Policy Thinking, Phil Goff!
Following a recent article on Auckland's transportation capabilities here on making New Zealand, Phil Goff's recent pronouncement on support for light rail, announced and reported in the New Zealand Herald on the 7th September, I find it depressing that a serious Mayoral Candidate has swallowed the "light rail" religious faith.
Regularly we have evidence of a economic "Walter Mitty" syndrome, where we think our city is on a par with Hong Kong, London, Brussels and other cities whose regional populations, histories and geographies are a whole world different from ours. Auckland, by global standards, is a small city and when benchmarked against similar cities of its size by population, there are certainly cities whose performance is far better in terms of congestion and housing affordability. Auckland's main priorities, like any other city, should first be providing its residents with a governance model and professional expertise that delivers in these day to day metrics that actually make for a 'livable' city. Instead we focus on inefficient models of transportation. Duplicating capital outlays on multiple public transport modes is wasteful in cities of less than 5 million people where the only public transport mode should be a 100% bus-based system.
Rail might make for great headlines and be attractive for tourists. However, while tourism is a source of employment, it is a poor payer in terms of wages for the majority of those in its sector: watch this very informative talk by Professor Sir Paul Callahan from 7:46 to 8:29 (but I recommend the whole 20 minute video)
Sir Paul Callaghan - Strategy NZ: Mapping our Future - March 2011
Therefore, even in large cities it should be a minor mode of travel within a city and in a small city like Auckland, it should be non-existent. What we have in Auckland is not only heavy commuter rail being built at an extremely expensive rate per mile, we now have the addition of light rail as a second rail mode! Rail, light and heavy, is also rendered grossly inefficient by any uphill travel - something that is guaranteed to happen in Auckland with its volcanoes.
The UN Habitat Program report "Streets as Public Spaces and Drivers of Urban Prosperity" should have been a bombshell to solid policy making here. It points out that the amount of street space a city starts out with, relative to built-on private property, is crucial for its ability to repurpose space for cycle lanes, Light Rail and pedestrian only areas. On that note, how does Auckland compare in transport corridors to enable this re-purposing in its urban area? The UN Habitat report provides four ways of measuring it:
Land allocated to streets.
Street density.
Ratio of land allocated to streets to street density.
Intersection density
Every year TomTom produce a congestion report for major cities around the world. While the report is not perfect, it does use data from TomTom users with respect to speed. The chart below shows the congestion scores, for 174 cities shows the congestion scores. Auckland is highlighted with a larger red dot than the other cities.
TomTom Congestion Scores, 174 cities worldwide
To evaluate whether the UN Habitat data has any relation to the TomTom data, the following three charts plot the proportion of land allocated to streets (#1 above), street density (#2 above) and intersection density (#3 above) against the congestion score for that city. What we are looking to see is if, as these three UN Habitat measures have a role in reducing congestion as they increase in value. Therefore the best fitting trend-line, by way of the highest R-squared value, was chosen.
TomTom Congestion versus Proportion of land allocated to streets
TomTom Congestion versus Street Density
TomTom Congestion versus Intersection Density
As can be seen the relationship is somewhat weak, but it would not be possible to argue that increasing the amount of land allocated to street is going to increase congestion; the same would apply to increasing street density and intersection density. The strongest relationship is between intersection density and congestion - if you increase the number of intersections then the general pattern is congestion decreases. Unfortunately the UN Habitat data is only provided for 23 cities - this will be followed up to see if more data is available.
However, it is interesting that intersection density has the biggest positive effect out of all the three UN Habitat data sets. The Auckland Transport Model, ART3, shows that there are a variety of trip purposes, a summary of which was discussed in an earlier article on Making New Zealand. When we consider that in most modern cities there is a plethora of origins and destinations because of the distribution of people is throughout the boundaries of the city and that commuting trips are less than 20%, then we can expect a huge variety of trips by spacial direction. Imagine installing one massive superhighway that everybody has to join even to make the simplest of trips then no matter how big that highway is - in the context of what the city's resident can afford to pay - it will always become congested.
If however there are a multiplicity of routes from all the possible origins to all the possible destinations, then the presence of intersections is needed if we are to avoid using more land for roads than is necessary, or having a spaghetti junctions everywhere, which may not be to our aesthetic liking!
Spaghetti Junctions (like this example in Birmingham, UK) has its place, but not everywhere! (1)
Therefore, the more intersections we have, the greater the number of routes we have and the less likely we will encounter congestion in our trip. Putting it another way, increasing the number of intersections increases the number of routes that we can take.
What we should be doing, if we are to provide a good transport experience, is to allow trips to take place over a wider area to reduce the number of vehicles that need to use common routes. We also need to make sure that the complex web of intersections is built in from the start, to also provide for a greater variety of routes. For those who think that spreading out is going to increase congestion, I would encourage you to read the earlier article linked a few paragraphs above: it is simply too complicated to provide a public transportation system that can provide reliable and frequent connectivity from every origin to every destination.
Thanks to Phil Hayward who provided some of the research data and thinking around this article.
(1) Original - Highways Agency photo on flickr - whose license permits such reproduction when properly credited
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