My post the other day about the importance of public transport in reducing car dependency’s financial cost, generated a lot of interesting discussion. There was a bit of debate over whether New Zealand mirrored the USA’s split in household expenditure (it seems we spend a bit less of our incomes on transport), but what there was general agreement on is how car dependency might vary from place to place – particularly across different parts of Auckland.
Using 2006 Census Data (yes I know it’s horribly out of date but for comparative purposes that might not matter too much), we can look at transport modeshare results by Census Area Unit (generally around 4000-5000 people). This tells us some interesting stories. Full excel worksheet here for your information.
Firstly, let’s look at Census Area Units (CAUs) with the highest public transport modeshare: It would seem that key characteristics of parts of Auckland with high PT use include proximity to the city centre and also proximity to high frequency services (bus, train or both). I’m pretty sure every single one of these CAUs is on the isthmus – and most of them fall within parts of Auckland developed prior to the Second World War. Interestingly, they have a pretty wide range of levels of car use and walking/cycling use.
If we turn to walking/cycling next, we see an even more dramatic concentration in and around the city centre – which is no surprise:
These areas with the highest levels of walking and cycling generally correspond with being those that have the lowest level of car-use, with Whenuapai West being an interesting exception (due to the airbase I imagine).
If we look at Census Area Units with the highest levels of car-use, unsurprisingly the first 20 are pretty much exclusively rural areas: Ormiston (the Flat Bush area) is an interesting inclusion there – though not surprising as back in 2006 there was probably no public transport and almost certainly nowhere to walk to. What the rural nature of these areas highlights is that by living in the countryside you really do become massively dependent on the private car.
The next 20 highest CAUs start to show us a few more urban areas: We definitely start to see a few more urban places here – though generally on the periphery (Weymouth, Dannemora, Wattle Farm, Silverdale etc.) This suggests that Auckland’s urban form in these peripheral areas isn’t really encouraging either the use of public transport or walking and cycling as viable alternatives to driving.
Taking things one step further, I was curious to see whether modeshare had any basic relationship with income – building on my hypothesis that many people in Auckland perceive the PT network to be so bad that their families own multiple cars – regardless of their income. So let’s firstly look at CAUs with the highest proportion of households earning over $100,000 a year: No super-clear pattern seeming to come through there. Many quite wealthy areas (Ponsonby & Grey Lynn) seem very willing to catch public transport, with many (Stanley Bay, Parnell, St Mary’s Bay) also very willing to walk or cycle to work. Perhaps this highlights the connection between richer areas being central and central areas being less car dependent, more than anything else.
Now let’s look at poorer areas, those with the lowest proportion of households earning more than $100,000 a year: The data is complicated a bit by a few very unusual CAUs (Gulf Islands in particular), but generally once again there doesn’t seem to be much of an obvious pattern. Some of these areas have comparatively low car dependency (Lynnmall being perhaps the best example), but many are pretty high – ironically including Mangere Station CAU, which has no public transport use at all even though it’s named after a (now closed) train station. Places like Manurewa and Papakura remain extremely car dependent – even though these centres have become two of Auckland’s busiest rail stations.
I probably need to learn more statistics to properly analyse the information, but the various tables above highlight a few things in my mind:
- Proximity to the city centre seems the strongest determinant of car dependency
- Rural areas are extremely car dependent
- Public transport use is highest in city fringe areas and along well established bus routes like Dominion Road
- Income, both at the high and low ends, seems not to be related to modeshare much at all, except through other correlations such as central areas being high income areas
What I’d really love is to see some of this information mapped. Guess I should take a GIS course next semester.
A reader has kindly mapped the car modeshare, which highlights to us in progressively lighter colours the areas with lower car modeshare – pretty much proving that proximity to downtown Auckland seems to be the most important factor in determining whether or not you drive to work: