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.

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  1. It does look close to completion however the scheduled completion date is not until 2012. Surely they can’t be that far ahead of schedule?

  2. I wonder if these projects are being deliberately tendered for or advertised with a longer time frame so they say how successful they are are bringing the contract in early and/or get financial bonuses for doing so.

  3. Well I’m certainly no expert but it does seem strange that it would take them four years to build a 6km stretch of motorway through mostly empty farmland. Everytime i have gone past it it looks like it’s pretty close to completion.

  4. A lot of the work on motorways appears to be involved with linking roads together; building the interchanges, building the junctions, etc. It’s not very demanding to build a road when nobody’s using it, but it’s rather more challenging to link those new roads to roads that already have traffic on them.

  5. An interesting aspect to this project is that the extension of the Northwestern motorway through to Brigham Creek has been quietly turned from a two lane road, as originally intended, into a full four lane motorway.

    I agree with Admin re the removal of lanes on Wiri Station and Hobsonville Roads. Actually you can take this a couple of steps further and actually cap the number of motorway lanes you have on the Isthmus. The city of Vancouver has taken this even further – no extra traffic lanes are permitted to be built in the city.

    So if lanes are added to the Western Ring Route, the same number of lanes could be removed or re-dedicated for public transport on SH1. Once the WRR is finished, this would have the effect of pushing a lot of through traffic out of the CBD and on to the WRR.

    The other thing that should be happening right now is instead of the Southwestern Motorway being ramp metered when it enters the Southern, the reverse should happen – with precedence being given to the WRR.

    1. I’m not concerned about the additional lanes for SH16 from to Brigham Creek Rd, adding them in now when you are building a whole new road anyway isn’t probably such an issue. If the road was already there then I would be more concerned.

      Also it might be a bit premature to push for WRR to become the primary road through the region, at least until Waterview is finished.

  6. “Fundamentally though, the worry is that I don’t know whether many traffic engineers understand the benefits of lowering road capacities.” That may be so for engineers, but any true Transportation Planner understands that contrary to NZTA funding guidelines congestion is not always a bad thing 😉

  7. Unlike Wiri Station Road, Hobsonville Road is a two lane road (one lane each way), so it is not possible to reduce the number of lanes. Council has plans to install a cycle lane on each side of the road, generally involving removal of parking on one side and involving some land purchase. Perhaps ironically the reduction in through traffic (which is currently fully saturated during peak periods) will allow traffic signals to be installed at major side roads which will help to re-balance flows to be more in favour of local traffic movements, provide pedestrian crossings etc, and improve safety at junctions. The signals could also increase the travel-time difference between Hobsonville Road and the motorway.

    I have also heard from a knowledgeable source that the motorway construction is currently well ahead of schedule, presumably as they have had periods of good weather.

    Some traffic engineers understand the benefits of improving the road environment for non-vehicular users :-). That may or may not involve reducing the capacity of the road.

    1. Yes Hobsonville Road is two-lanes at the moment. I guess the point I’m making is that we should ensure it stays that way. A few signals would be good actually, to break up the road, slow down the traffic a bit and connect the side-streets a bit better. It would also obviously make it easier to cross the road – which must be nigh on impossible at the moment for pedestrians.

  8. Interesting the Hobsonville Road speed camera was the third busiest in the country in 2006, suggesting that something is not right with the Road layout. http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10363184
    A quick look on streetview suggests this is not suprising given the current layout with wide lanes, a continous wide median, a shoulders with no cars parked. Having the footpaths right next to the traffic lane is also not good and something that should be fixed.

    Interestingly the ARTA Regional arterial road plan suggests that Waitakere CC were planning to put bus lanes along the length of Hobsonville Road as soon as the motorway opens. Although I applaud the sentiment I’m not sure of the point of this, especially with urban development on one side only. One would would think that local bus services would use the local loopy streets for services going to Westgate and the future Hobsonville town. Any express going from Westgate to North Shore would use the motorway.

    Also hope a quality pedestrian and cycle connection is provided to link West Harbour and Westgate, at the moment its completely lacking.

    1. Hobsonville Rd is the current MUL boundary but after the motorway opens it will shift to the motorway (which makes sense). That undeveloped land will not stay that way for very long and I think that the Waitakere city plans were to have large parts of it as commercial development rather than residential.

  9. Have you seen the latest renders of how Gt. Nth Rd. will look? Nothing will be different except the plan to plant some grass in the medians – talk about failing to improve the general amenity of a suburb they’re destroying.

  10. Yeah I’ve read the transport evidence. Pretty much NZTA and Auckland Council/Auckland Transport pointing at each other saying “your problem”.


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