Cross-town routes

Cross-town routes, by which I mean routes that don’t travel to or via the CBD, are quite a conundrum when it comes to planning an effective public transport system. Everyone kind of realises that we need cross-town routes – particularly in a city such as Auckland where 88% of the region’s jobs are located outside of the CBD. However, at the same time the cross-town routes that we have are generally not particularly successful/popular, making it difficult to justify having more of these routes.

Auckland does have a number of cross-town routes at the moment. On the isthmus there’s the 006 route from Unitec to Newmarket, the 007 route from Pt Chevalier to St Heliers, the 008 route from New Lynn to Otahuhu and the 009 route from New Lynn to Sylvia Park. There are also a couple of other rather random cross-town routes, such as the 010/011 and the 12 route from Pt Chevalier to Newmarket. However, apart from the 007 route (at a pinch), none of the other routes seem particularly well supported and generally run at very low frequencies, or at certain times of the day only (such as peak hour). This doesn’t exactly make them the kind of routes that people would rely upon to make trips other than their daily commute, and even then it would seem as though public transport routes for non-CBD jobs have an incredibly low “capture” – basically only those who can’t afford a car (and the odd weirdo like me who used to catch the bus to work in Avondale even though driving was faster).

There’s a reasonable argument that in order to increase public transport use, we need to centralise employment more – preferably in the CBD, but if not that then focusing employment into particular nodes will make it easier for those areas to be served by public transport. Traditional routes, from the suburbs to the CBD and then back out again, are really only useful if you work in the CBD, or happen to work and live on the same bus/train route. Of course, in a city where employment is dispersed, the chances of this happening are fairly low.

Melbourne transport academic Paul Mees has analysed in great detail ways in which we can make public transport more useful and effective in low-density, highly dispersed cities – which Auckland is a pretty classic example of. At a theoretical level, he describes a situation where let’s pretend we have a city with its jobs being dispersed in a completely universal fashion (probably the worst case scenario possible for public transport). In the diagram below each population/employment point is shown as a red dot. With traditional routes generally running all in the same direction (from the suburbs to a CBD point), we can see that someone living along one of the routes can only access 9 of the other 99 points – barely 10%:

In fact, if we are obsessed with providing “point to point” travel between work and home, without any transfers, no matter what route we take, the number of points accessed is pretty low (route 1 below still only serves 18 out of the 100 dots). To increase the number of points served it is necessary to make the route really long, slow and windy (route 2 below serves 42 points, but would probably take about a year to get there!). Auckland has far too many “route 2’s” in my opinion, which generally lead to incredibly slow journey times and dissuade anyone who doesn’t have to from catching public transport. There is where cross-town services become important. They are necessary to “link up” the other routes, and create a system that is a true network, catering for a wide variety of trips beyond simply CBD-focused ones. Let’s have a look at what throwing in a few cross-town routes does to the system in our first diagram:

Now assuming that it’s easy enough to walk the distance between one red dot and another, through running 10 different routes (five vertical, five horizontal) we have now brought every single dot within an easy trip of every other – with the key aspect which enables this being the transfer. Below we have an example which shows exactly how you can get from any point on the network to any other point. Interestingly enough, you always have two different options to get from the start of your trip to the end, which means that you can choose the one that either comes along first, or you can choose the one that you have learned through experience will have the least congestion.  In the above example, if you took the purple option you would need to walk the last little bit, or catch another bus. That might make the blue option more attractive, but importantly you have a choice here.

Somewhat unfortunately, Auckland never built its streets in a perfect grid-layout, which makes creating those cross-town routes quite a challenge beyond the central isthmus area which has a reasonable super-grid of main streets (New North, Sandringham, Dominion, Mt Eden & Manukau in a north-south direction, Balmoral and Mt Albert east-west). However, I think it would certainly be possible to improve our cross-town links and eventually create a rather warped – but still recognisable version of the system above. Perhaps something like this could form a base for the network: The purple lines indicate the “better frequency” routes that Auckland has at the moment, which run along a traditional suburb-to-CBD alignment, while the blue routes are (generally) new or significantly altered cross-town routes that would “link up” all the purple routes to create a true network.

Of course there’s something huge missing from this map, and that is the rail system and how it works. A lot of previous posts I have written talk about the need to have many more feeder buses, whereas these above routes tend to mainly show long-haul routes. Well I think the answer is that we need both. Perhaps the routes shown above could end up being the only non-feeder routes throughout the Auckland isthmus, with all other areas served by buses that feed into train stations or into the more high frequency services that may potentially become light-rail in the future (Dominion Road for example).

I do wish Auckland had developed with more of a grid street network though. It would make life a LOT easier.

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