A number of motorway projects underway at the moment – like the Manukau Connection, the Hobsonville Deviation and (not quite yet underway) the Waterview Connection – will have significant traffic reduction benefits for the local roads that they bypass. Well, actually I should say that these projects potentially will have significant traffic reduction benefits for local roads they bypass – because unless these benefits are ‘locked in’, over time it is inevitable they will be lost to induced demand.
What do I mean by “locking in” the traffic benefits of motorway projects? Well let’s take the Hobsonville Deviation as an obvious example, as one of its biggest benefits will be a significant reduction of traffic along Hobsonville Road – which is the SH18 link between West Auckland and the North Shore at the moment. Hobsonville Road is a pretty horrible road – only two lanes, 50 kph speed limit (so it takes forever to drive along), a pretty messy mix of local traffic and general ‘through-traffic’. When the new motorway opens, a huge chunk of its through traffic will be removed, and put onto the new motorway. I took a photo of the progress on this motorway yesterday – and it doesn’t seem too far away from completion:
The completion of this project will enable Hobsonville Road to become a much more normal arterial route – still potentially quite busy – but with potential to be a great main street to new development that will happen in this area over the next few years.
When the new motorway opens, most through-traffic will take the motorway, while I imagine even a lot of local traffic will try to spend as little time possible on Hobsonville Road before getting to the new motorway. Hobsonville Road will be much nicer for pedestrians, cyclists, there will potentially be the opportunity to create bus lanes and other forms of bus priority without stuffing up general traffic too much – simply because there will be, at least for a while, relatively little general traffic. However, over time there will be a lot of increased development in the area and slowly Hobsonville Road will fill up again – probably ending up eventually back where it started in terms of congestion, unfriendliness for pedestrians, cyclists and public transport – and generally once again be a huge gash sliced through the area. That is, unless we ‘lock in’ the benefits of the motorway project.
But how does one do that? How can we ensure that the traffic reduction benefits of this motorway project stick around for a long time? Somewhat counter-intuitively, what I think we must do is drastically cut back the general traffic capacity of Hobsonville Road once it no longer becomes the main road through the area. The same is true out in Manukau City, where the massive capacity of Wiri Station Road needs to be sliced back severely now that it’s not the main link between SH20 and SH1 any more. It is critical that most vehicles are encouraged to take the new motorway – both through it being a higher-speed environment but also through the old route becoming much slower speed and generally having a much more ‘local’ scale. Along Hobsonville Road, there’s the ability to start working on that Henderson to Albany QTN/RTN that has been listed on many plans for many many years. Along Wiri Station Road there’s the ability to create something of a “main street” for Manukau City – tying together Rainbow’s End with the main shopping centre and so forth.
Fundamentally though, the worry is that I don’t know whether many traffic engineers understand the benefits of lowering road capacities. I worry that the hugely wide, but initially nearly empty Hobsonville and Wiri Station roads will be seen as huge success stories, rather than as the opportunity to rededicate some of this unnecessary roadspace to more sustainable transport options. In Auckland we see many examples of huge road capacity being constructed a very long time before it is necessary (like all the four-lane roads through empty fields in Albany and Flat Bush) without any public transport, cycling or other pedestrian priority measures. This inevitably sets up these places to be completely auto-dependent. Motorway links that take a lot of traffic off main arterials provide us with a ‘second chance’ to give better priority to non-automobile transport.
We need to make sure that opportunity is taken. We need to rededicate that roadspace and lock in the real benefits to communities of the new motorway bypasses.