Density and public transport usage

Posted: October 29, 2012 in Transport, Urban planning
Tags: ,

The 2011 census data on journey’s to work (JTW) is set to be released this coming Wednesday, and it will be interesting to see if there have been any changes since the 2006 data. To prepare for this, here are some links to a few recent blog posts by Chris Loader at Charting Transport and Alan Davies at The Urbanist on the topic of mode share and urban density.

Is Los Angeles really the densest city in the US? – The Urbanist (17 Oct 2012)

This post points out that if you look at average densities alone, then Los Angeles is actually more dense than New York. However, this is due to New York having an incredibly dense core surrounded by urban sprawl at very low densities. A better measure is the population weighted density, which measures density based on the population density for people, rather than for parcels of land.

Population density for New York and Los Angeles based on distance from City Hall. Click on image for higher resolution. (Source: The Urbanist)

Comparing the residential densities of Australian cities (2011) – Charting Transport (19 Oct 2012)

Taking a more Australian centric look at population density shows that Sydney has the highest density of all Australian cities. In fact, Sydney’s median density of 33 people per hectare is closely followed only by Melbourne at 28, with no other city being above 22. It argues that if suburbs are defined are areas with a population density of 30 people per hectare, then Sydney’s average density doesn’t drop below 30 until you are 39km from the CBD, compared to 9km for Melbourne.

Population density for Australian cities. Click on image for higher resolution. (Source: Charting Transport)

Does public transport use correlate with density in Australian cities? – The Urbanist (21 Oct 2012)

The question then arises about whether there is a link between population density and public transport use. Alan Davies finds that weighted population density and public transport use have an R squared of 0.943 when a logarithmic curve is fitted along the graph below, which indicates a very strong correlation. However, he points out that high public transport use is more likely to be caused by dense employment centres (which is covered more in the subsequent Charting Transport blog post).

Public transport mode share vs population density for various Australian cities. Click on image for higher resolution. (Source: Charting Transport via The Urbanist.)

How did Sydney get to work in 2006? – Charting Transport (26 Oct 2012)

Something that sets Sydney apart from other cities is a large number of dense employment centres, whereas other Australian cities tend to just have their CBD. And public transport usage is higher for Sydney both in CBD travel and travel to non-CBD employment centres in other cities (e.g. the proportion of workers in Bondi Junction, North Sydney, Parramatta, Chatswood, and St Leonards who travel by public transport ranged from 34% to 53%, whereas no centre in any other Australian city was above 15%). However, this is also due to state and local governments in Sydney restricting the amount of parking available for workers, meaning many of them have no choice but to take public transport.

Employment density in Sydney. Click on image for higher resolution. (Source: Charting Transport.)

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