The SH1/SH26 roundabout – what is going on?

In this recent post Matt asked why we were still building dangerous intersections. One part of his post caught my eye, specifically proposed changes to the intersection of SH1 and SH26 in the Waikato. The location of this intersection is shown below.

SH1 and SH26a

 

You can see that the intersection exists firmly within the Hamilton urban area. Moreover,  I understand the area to the east is planned for residential growth in the future. I.e. there will be more and more residential development to the east.

The reason this caught my eye is because the proposed changes, in my opinion, seem likely to result in a horrific clusterfuck of an intersection that will, at a minimum, destroy urban amenity and, potentially, result in pedestrian carnage. In my opinion, this roundabout design is completely inappropriate for an urban area. And unlike NZTA I don’t agree t hat potential delays to vehicles are sufficient reason to provide wholly unsatisfactory facilities for pedestrians. Facilities that are so lacking that they seem likely to increase the risk of injuries to pedestrians who need to cross at this intersection.

The proposed changes are illustrated below.

Hamilton SH1 -SH26 upgrade

 

Now I should mention that the NZTA press release for the changes mentions an additional pedestrian crossing is to be located on SH26 to the east, which I presume (although can’t be sure) is beyond the extent of works shown above. The press release also noted the presence of a pedestrian underpass on SH1 to the south, which is being retained in the new design.

What NZTA are proposing for the southern and eastern approaches to the roundabout is relatively poor practice and ill-suited to an urban area such as this.

But perhaps most importantly, the proposed pedestrian facilities don’t seem to address what happens on the western approach to the roundabout. As anyone can easily see from StreetView below, NZTA’s beautiful junkspace landscaping is *already* being severely trampled beneath the feet of hapless pedestrians as they scamper across the existing road. QED there’s an existing problem that needs to be resolved, not ignored as the proposed design has done.

Crossing

Anyway, I was sufficiently motivated by this proposal to start digging for more information.

The background study for these intersection changes was completed in 2008. Given that it’s now almost 8 years since the study was completed, I thought I’d go and look at traffic volumes since that time. In the figure below I’ve totalled the AADT on the two closest counts on SH1 and SH26 over time (NB: This will double-count many vehicles, which is why the total AADT shown here is significantly higher than the figure of 37,000 vehicles per day using the intersection that is quoted in the NZTA in their press release. Nonetheless it’s likely to be broadly indicative of general trends in AADT).

AADT

 

The volumes bobble around a bit, although current AADT is about 3% below the level achieved in 2008, i.e. the time that the report supporting the proposed changes was developed. Is it reasonable to assume that vehicle volumes will increase or decrease from here?

Well, there’s some growth out this way so it’s plausible to suggest there may be more demand. On the other hand, there’s one major question that I’m not confident is addressed by the studies associated with this upgrade: The Waikato Expressway, specifically the Hamilton section.

For those who aren’t familiar with this project, it’s part of the RoNS programme.

While I’m no fan of the RoNS programme per se, if these projects are to go ahead then I would at least expect NZTA to maximise their potential benefits, especially with regards to re-configuring parallel routes to support more livable urban places. In this context, the Hamilton section of the Waikato Expressway is  high-speed, high-capacity route that seems likely to shift vehicles away from the existing SH1 and away from this roundabout. Construction of the Hamilton section is expected to start in 2016 with a target opening date of 2019.

I note that the NZTA website states that the Hamilton section of the expressway will:

  • Connect the Ngaruawahia section of the Expressway, completed in late 2013, to the Cambridge section, due for completion in late 2016.
  • Reduce traffic congestion and improve safety on Hamilton’s local road network by significantly reducing through traffic.”

And yet NZTA’s proposed changes to the SH1 and SH26 intersection (which appear to have been formulated prior to the RoN being confirmed) are designed to increase capacity.

One has to wonder why the NZ Transport Agency is spending $2 million to create a situation that is more dangerous for pedestrians than the present one, while at the same time spending the best part of half a billion dollars building a high-speed bypass around the same intersection.

Call me a simpleton if you will but I would have thought the more logical sequence of actions would be:

  1. Complete the Hamilton section of the Waikato Expressway in the next 3 years as planned; and
  2. Monitor changes to vehicle volumes in response to growth (which apparently is quite low at the moment) and expressway; and
  3. Develop options for the intersection which respond to these changes, but which are also appropriate for an urban area.

In terms of #3, this really brings us full circle. I cannot understand why NZTA would think the proposed design is appropriate for an urban area. I can tell you that in my opinion it’s most certainly not. While I’ll reserve my full and final judgment until I have more detailed information to consider, the proposed intersection seems to compromise pedestrian safety to a level bordering on negligence.

I know that’s a big call so let me present some reasons why:

  1. The design does not seem to meet the present need for a pedestrian crossing on the westbound SH1 approach, e.g. to access the adjacent school. There is already demand for this pedestrian movement, as we can see from StreetView. This demand will only increase as the area develops in the future.
  2. The approaches are wider than the current facility. The western approach on SH1 , for example, is three lanes wide. This will increase the distance pedestrians will have to cross before they reach the landscaped sliver of land in the middle of the road.
  3. The design incorporates features that seem likely to increase vehicle speeds. The western approach on SH1, for example, now includes what is effectively a “slip lane” for vehicles travelling through. This features will enable/encourage vehicles to maintain their speed on their approach to (and exit from) the intersection. This will increase risks to pedestrians who (legitimately) need to cross the western approach, and the severity of accidents.

I draw two *preliminary* conclusions from all this. First, the proposed changes to the intersection is unacceptably dangerous for pedestrians and should not proceed as designed. Second, the proposed intersection has been designed without consideration of the Waikato Expressway and thus are likely to represent poor value for money and low strategic fit.

I’d really like to know what others think: Am I mis-reading the situation here? Or is it as bad as it looks? An outdated and seemingly dangerous design being imposed on what is very much an urban area, just prior to a major expressway bypass opens? What is going on?

Funding the Basin Flyover Fight

Yesterday the Architectural Centre in Wellington have launched a fund raising campaign to fight NZTA’s continued waste of our money on expensive lawyers for their hopelessly unimaginative and retrogressively conceived Basin flyover project. Here’s the Give-A-Little site with a recap of the situation.

Basin Appeal

 

Breaking down Harbour Bridge volumes

I regularly keep track of a number of statistics about transport and one of those is traffic volumes from the NZTA. Recently I noticed an anomaly with the figures for the Auckland Harbour Bridge. Previously volumes were reported as:

  • Centre Span
  • Left Clip-On
  • Right Clip-On

The monthly data for March and the annual data for 2014 (released in March) was different, instead reporting just Northbound and Southbound traffic volumes – the annual data also included the clip-ons but not the centre span. That in itself isn’t such an issue however the total traffic volumes were quite different, even for previous months/years. An example of the difference is shown in the chart below of annual traffic volumes. You’ll also notice that the volumes are up slightly – although they are still less than they were in 2005 and in percentage terms is low considering Rapid Transit services like the busway are growing by double digit figures. The chart also includes the traffic volume predictions found in the most recent business case for another road harbour crossing.

AHB Annual Volumes to 2014

So seeking an answer for discrepancy I asked the NZTA why the figures were different. The answer is below.

The original site was a National Telemetry Site with loop detectors on the two clip-on sides and an infra-red detector over the four centre lanes. This equipment used on the centre span could not determine directionality and loops could not be used due to the steel deck (the clip-on counters are on the concrete deck north of the main span).

The Auckland Motorway Alliance (AMA) established a count site just north of the bridge some years ago to collect directional data, but it was noticed that the AMA counts and the Telemetry site counts were drifting apart. The problem was with the centre span equipment, which was missing more vehicles as time went by. Therefore, it has been decided that the data from the centre span counter was too unreliable to use.

The Telemetry site was life expired anyway, so the AMA site will become the new Telemetry site. I am told that the clip-on counters are still providing reliable data, so there is no need to decommission them.

That seems a pretty reasonable explanation however as the monthly data released so far only extends back to March 2014 I asked if any further data was available. What I received back surprised me. I did receive some extra monthly data but far more interestingly I also got two years of hourly data by direction – from 1 January 2013 to 31 December 2014. Below are some of the insights we gained from that.

First up results by the day of the week. I was quite surprised to see that traffic builds up over the course of the week with an average difference between a Monday and a Friday of over 15,000 vehicles per day. The busiest single day over that two year period was December 19, 2014 when over 200,000 vehicles crossed.

AHB Traffic by Day

Breaking that down further by time the table below shows that while Fridays have the highest overall volumes, the strongest peaks occur earlier in the week which I can only guess is due to a lot of people rushing to get home whereas on a Friday the peak is smoothed a little, perhaps from people leaving work earlier or staying at work longer socialising. You can also notice that the late night/early morning volumes over the bridge are much higher than other days of the week from people ou

AHB Traffic by Time and Day

Click to enlarge

Showing traffic volumes over the course of the average weekday we get the chart below. I was quite surprised to see that the afternoon peak was stronger than the morning peak.

AHB Traffic by Hour

The data allows us to break that down further including by direction

AHB Traffic by Hour by Direction

While volumes peak in the morning and afternoon I was interested to see how things compare on a per lane basis as the moveable barrier on the bridge means that in the peak direction there is an extra lane available. It is often stated that a single motorway lane can move about 2,000 vehicles per hour. As you can see the volumes on the Harbour bridge fall short of that and peak at around 1,700 per lane. It’s also interesting that at times when the bridge is in a 5-3 configuration that lane volumes are similar.

Note: I’ve estimated the times that the barrier is moved as I’m not 100% certain.

Lane Capacities

I suspect it will be very hard for the bridge to hit any maximum capacity as it is limited by the motorways either side of it. That is also one of the major flaws of any plans to build and additional harbour crossing. You’d have duplicate or at least widen much of SH1 to either cope with the volumes or allow the connections to be used to their potential.

Lastly it’s worth considering the role that buses now play in the Harbour Bridge. Over the two hour morning peak (7-9am) around 200 buses cross the bridge southbound yet they carry around 9,000 passengers which is well more than the bridge carries in an a single morning peak hour. That points to one of the big benefits of PT investment, it’s capacity abilities. By having a strong, congestion free route it allows us to take the edge off volumes and move many more people at a time they want to travel. Imagine the impact there would be if tomorrow all the PT users who currently cross the bridge by bus instead tried to do so by car.

Overall fascinating data so thanks to the NZTA for providing it.

Deluge

This is a Guest post by Wellington Architect Guy Marriage

Wellingtonians get a hard press in the Auckland papers sometimes, but last Thursday we thoroughly deserved it. We are normally a fairly resilient lot, and put up with more than our fair share of howling wind and torrential rain at times, but regularly battle through with trains and buses all performing admirably. Even our regular rush hour traffic jams only just live up to their name, and are normally well over within the hour. We know about Auckland’s horrific traffic, and sympathies, we really do. But last Thursday, we suffered a total melt-down, and for a supposedly heavily resilient city, that was a pretty big fall from grace. So what happened?

brollies

As you may have heard, broadcast all over the evening news, we had a bit of excess rain. About 8 times more rain in an hour than we get in a month, or some such unbelievably wet statistic like that. And then the big wet went on and on, and eventually we had some slips, where our glorious hills decided they didn’t want to be vertical any more, and so they poured out over the flat bits along the edge of the water. Unfortunately for Wellington, all of our escape routes out of the city run along the same flat stretch of road to the Hutt, and so a small slip on the Hutt Road blocked off a route north along State Highway 2, diverting all the SH2 traffic to SH1. Doubly unfortunate really, because on the other side of the hills, SH1 was also blocked off, and that meant they had to send all the traffic back to SH2, over SH58. There is only one other road, the Paekakariki Hill Road, which is narrow and windy, and is frequently blocked by slips anyway, so inevitably that blocked up too. No way in, no way out. The capital was blocked off from the rest of New Zealand. Did you miss us?

WellingtonThursday

The road was therefore bumper to bumper traffic jam from Wellington all the way to Porirua, and also at a standstill over the hills back to the Hutt Valley on the other side. If you’re not from Wellington, then none of that will make sense, and the nearest I can give you as an example is if the Harbour Bridge was closed, and the NorthWestern motorway was closed as well, and all the traffic between Manukau and Auckland was diverted via Puhoi, and then all the cars stopped moving. Yes, exactly, a stuff-up in traffic terms of monumental proportions, one considerably worse than the average Friday night jam in Auckland, and we will inevitably face calls for yet more roads to be built, just in case this happens again.

NZTA WGTN flooding

But wait, there’s more. Surely none of those road closures matter, as Wellington is the most public-transport oriented city in the nation, is it not? Well, yes, but on Thursday even that let us down as well. Every single train to every single destination was cut, and the central Wellington Railway Station was closed down. That’s a station that normally is about 3 times busier than Britomart, and we have shiny new trains too for the most part. But that accursed rain had deluged rocks and washed out gravel over every set of tracks. Replacement buses normally suffice when there is a traffic setback, but with all the roads and all the rail out, there was no way that the few remaining charter buses could keep up with the demand. The city actually took the unheard of step of telling all commuters from out of town to stay in town, spend the night with friends, to rent a room or borrow a couch, and give up entirely on moving anywhere. I’m not sure if that has happened to any city in living memory before, outside of a war zone. Even when Hurricane Katrina hit New Orleans, or when Super-Storm Sandy hit New York, they were still able to move people in and out of the city. But not Wellington, not last week. The only methods of transport still working were the planes (if you wanted to fly to Auckland and drive back down to Upper Hutt) and the ferries, which gave you a choice of sailing through the storm to Picton, or in a much smaller ferry, riding the waves up to Petone beach. Except of course that Petone beach has a damaged pier, and one of the small East-West Ferry boats was out of action, so that left just one small catamaran sailing back and forth to Petone all evening. I was fully expecting my floor to be full of refugees from the storm, but it was, miraculously, fugee-free.

NZTA WGTN

Wellington train_4740

Not that it really made the slightest bit of difference to Wellingtonians however. Within the city itself, there was a fair bit of wetness, more than usual, but nothing was broken. Everything still worked, everyone got home. Buses still ran, taxis still taxied, and cyclist continued to ride on their non-existent cycle network. We haven’t got a cycle network yet, because some pathetic councillors went feral, and have slowed everything down for reasons known only to themselves. We are, it seems, the only city in New Zealand with a pro-Green, fervently cycling Mayor, and yet we have not a single functioning separated cycle lane anywhere of any use on any major traffic route, which seems just a little bit odd. While the usual dips and hollows were fuller of water than usual, it seemed to me that the city performed admirably well, and lived up to its resilient reputation. You could have even thrown in a moderate earthquake or two, and the city would have shrugged them off as well, due to the steady stream of strengthening projects that have been going on. We’re a city that is like a brand new iPhone 6, already with a sturdy waterproof, shockproof rubber case on, and you could drop us from the upstairs balcony and we wouldn’t break, at least not completely. But we might bend a little if you sat on us.

But what this points to is that while Wellington City might be tough enough in parts, its the Regional Council and NZTA that were shown up as monumentally unprepared for disaster. I think we have just seen the biggest case for abolition of the Regional Council, right there. What if it had been a real, serious disaster, not just a few hours of torrential rain? The Civil Defence motto down here is “Get Through.” Clearly, that is not something that we yet can do.

WellingtonTransmission

NZTA have started work on the billion dollar highway known as Transmission Gully, an ironic name as they could only start work there when they had removed all the transmission lines, in case they fell over while they were digging out the gully road. One day, after an inevitable cost inflation to (probably) nearly two billion dollars, there will be a new road north, two lanes each way, all the way, and a new Petone to Granada link road – and you know what? If both of those roads had been built already, those other traffic snafu may well have happened just the same. The Petone to Grenada route will have to involve the moving / removal of some eight million cubic metres of rock, which wont be an easy task. The Transmission Gully route still relies on sending all the traffic along the waterfront and up the Ngauranga Gorge, both of which were heavily affected by last weeks rain, with several small slips/rockfalls and a lane taken out of action in the Gorge. Transmission Gully is also sitting firmly on an earthquake fault line and highly susceptible to slips as well, so there is a lot of work to be done securing hillsides before that route will ever be “safe”. We need NZTA to try a whole lot harder to battle-harden the existing network and we need Kiwirail and GWRC to make sure that public transport is a whole lot more resilient down here. 

“Why economists tend to be in bad odour …” – Cycleways in Christchurch

In an 1879 essay, Francis Walker tried to explain “why economists tend to be in bad odour amongst real people.” Walker, who went on to become the first president of the American Economic Association, argued that it was partly because economists disregard “…the customs and beliefs that tie individuals to their occupations and locations and lead them to act in ways contrary to the predictions of economic theory.”  Frank et al  1999

As some of you may be aware, Christchurch City Council has applied for NZTA funding to develop the network of major cycleways illustrated below.

majcycroutes-may14

This economic appraisal of this investment is discussed in detail in this blog post. The benefit-cost ratio for the $160 million investment was estimated using NZTA’s Economic Evaluation Manual to be 7:1, with the benefits of the project breaking down as follows.

chchcyclemodelbenefits

All well and good.

Until about a week ago when two economists from the University of Canterbury, namely Glenn Boyle and James Hill, released their review of the business case for the major cycleways network. Based on their review, Boyle and Hill conclude the actual BCR is more likely to range from 0.7 – 1.6. They reached this conclusion for the following reasons:

  1. Fuel prices – Rather than the 40% increase in real fuel prices assumed in the business case, Boyle and Hill suggest a more reasonable assumption is constant fuel prices. This reduces the BCR to 6.0.
  2. Time savings – Boyle and Hill calculate the average time saving per vehicle trip and conclude that because it less than 6 seconds, that these benefits should be discounted. This reduces the BCR to 4.6.
  3. Safety benefits – Boyle and Hill argue that the procedure used to calculate safety benefits is designed only for small projects costing less than $5 million. Removing these benefits reduces the BCR to 3.8
  4. Health and environmental benefits – Boyle and Hill argue that the procedure used to calculate health and environmental benefits is designed only for small projects costing less than $5 million. Re-calculating these benefits reduces the BCR to 0.98 – 2.3
  5. Discount rate – the business cases uses a 6% discount rate; Boyle and Hill argue “market realities suggest this is probably too low”. Using a discount rate of 8% reduces the benefits to 0.7-1.6.

Oh dear.

I’ve subsequently reviewed Boyle and Hill’s review. My general conclusion is that while they make some valid points, they miss the mark in the places that matter. This in turn means that their conclusions are at best unsubstantiated and at worst simply wrong.

The key issues I find with their analysis are summarised below.

The first issue relates to their grounds for dismissing time savings. First, Boyle and Hill the divide total (estimated) time savings by the total (forecast) number of vehicle trips in Christchurch so as to calculate the average time saving per vehicle trip. They then reason that because the average time saving per trip is ~6 seconds, then the time saving benefits are too trivial to be included in the business case.

This analysis smacks of the sort of erroneous logical reasoning that one would critique in a first year statistics course.

Consider the statistical distribution of time savings that might result from cycle investment. It’s reasonable to suggest these savings will not be distributed evenly.

More specifically, the time savings will accrue primarily to vehicle trips that occur within specific corridors and at specific times. That’s certainly what the modelling of cycle flows seems to indicate, as shown below. From this map one might expect very small time savings for vehicle trips in areas such as the airport, Brighton, and Banks Peninsula, with larger time savings for vehicle trips travelling in the peak direction on key radial corridors.

Christchurch cycle network demand map

The need to consider the distribution of time saving can be illustrated with a stylised example. Imagine a city where there are 1,000 vehicle trips, and where a proposed cycle investment will save 2 minutes for 50 vehicle trips, while the remaining 950 vehicles trips are unaffected. The average time saving in this city is only 6 seconds per vehicle trip, even if every vehicle trip affected by the investment actually saves 2 minutes.

The takeaway message is that the localised time savings in a large transport network cannot be accurately represented by the average time saving per vehicle trip. The latter metric may indeed obscure what are tangible savings for a small number of vehicle trips.

Or, to put it another way, if Boyle and Hill wanted an even more sensational figure, then they could have averaged time savings over all vehicle trips in New Zealand rather than just Christchurch, and concluded that the project would save less than half a second per trip. But that would be even more ridiculous.

Reductio ad absurdum; QED Boyle and Hill’s dismissal of time savings is unsubstantiated (NB: One could of course analyse the distribution of time savings and consider only those savings that were above a certain minimum threshold, but Boyle and Hill have not done this).

The second issue relates to their choice of an alternative discount rate. The major cycleways project is a transport investment which is seeking funding from NZTA’s land transport programme.

Let’s make this very clear: NZTA specify that a discount rate of 6% is to be used when undertaking economic appraisals of transport investments. It is therefore entirely appropriate for the business case to use a 6% discount rate. If Boyle and Hill have an issue with the discount rate that has been chosen by the NZTA, then they should raise those arguments in an appropriate forum – not pretend it’s an issue associated with the major cycleways project.

At this point it’s worth pausing for a moment and simply noting that if we add back in even 50% of the travel-time savings and use the 6% discount rate stipulated by NZTA, then the BCR for the cycleways project is likely to return to respectability – even if we accept all of their other points. And I don’t …

The third issue relates to their discussion of travel behaviour change. Boyle and Hill question the magnitude of travel behaviour change, but ignore that the business case takes a conservative view of behaviour change when compared with the results of stated preference surveys.

Stated preference surveys in Christchurch suggest that up to 30% of people would be willing to switch to cycling if sufficient safe infrastructure was provided. At present, the Census suggests that around 7% of people in Christchurch cycle to work, while the Household Travel Survey suggests that around 3% of total trips in the Canterbury region are made by bike.

The modelling did not conclude that cycle mode share would increase to 30%. It took a much more conservative view, which is that the cycleways would boost the number of cycling trips by 15-35%, which would imply an increase in mode share of 1-3% to between 5-10%.

A bit of international context would help here. Other cities that have invested in transformative changes to cycling infrastructure have experienced much larger increases in cycling mode share. For example, the Dutch only started investing in safe, quality cycling infrastructure in the 1970s. Today, many Dutch (and Danish and Swedish) cities have cycle mode shares in the range of 20% to 40%. Moreover, more modern cities like Portland have achieved cycling mode shares approaching 10%. QED the travel behaviour change assumptions in the modelling are within the range of what we observe elsewhere.

The fourth issue is that Boyle and Hill have misread the EEM guidance on analysing cycling benefits. They claim that cycling benefits have been estimated using an inappropriate (“simplified”) procedure. However, that’s simply not true. The values used to calculate per-km benefits for cycling are part of the core EEM (Appendix A20, if anyone’s interested). QED it was appropriate for the original business case to include these benefits.

The fifth issue is that Boyle and Hill make non-standard assumptions about fuel prices. They criticise the modelling for assuming that real fuel prices will increase. However, the assumptions in the business case are based on modelling published by MBIE – who are hardly a bunch of peak-oil alarmists. Boyle and Hill’s critique basically boils down to “oil prices are around their historical norm”, therefore we should not assume any future increase in price.

As economists, they should know that past performance may not be a good guide to the future.

Boyle and Hill argue that crude oil futures quotes are expecting current prices will persist, although I understand these contracts 1) typically extend out only for the next decade or so, and 2) the liquidity is fairly low in more distant future years. In contrast, NZTA stipulates a 30 year evaluation period for similar transport projects. Moreover, unless Boyle and Hill have an alternative (forward-looking) model of fuel prices, as well as evidence that their model is more accurate than MBIE’s, then their objection to the fuel price assumptions used in the business case is somewhat vacuous.

If, as it seems, Boyle and Hill’s real target is NZTA’s evaluation methods, then their critique of the cycleways is at the very least misplaced. Christchurch is proposing to invest a decent amount in cycleways, but that expenditure is dwarfed by state highway spending. If, for example, Boyle and Hill applied the same attention to the $11 billion RoNS’ programme, then they’d find some projects which start out with BCRs less than 1.0, even with more uncertain agglomeration / wider economic impact benefits included from the outset.

MoT state highway BCRs 2005-2012

 

A serious investigation would have at least considered this wider transport investment context, before honing in on the cycleways project as perhaps a case study. And even then it’s a relatively non-representative (and unimportant) choice of case study.

So where does this leave us?

Well, if the aim of Boyle and Hill was to create clickbait for anti-cycling neanderthals, then they can rest happy in the knowledge that they have done their job exceptionally well.

However, if they wanted to foster more informed public debate on the merits of the major cycleways project, or the business cases for transport investment in general, then they have clearly and demonstrably failed. It’s especially unfortunate their review comes across as a deliberately sensationalist hatchet job with largely unsubstantiated and/or incorrect conclusions. By extension, their review does not – as they claim – call into doubt the key finding of the original business case, i.e. the investment in major cycleways represents a relatively effective transport investment. For these reason I wouldn’t expect their review to hold much sway with Christchurch City Council and/or the NZTA.

Postscript: While Boyle and Hill’s review is, in my opinion, “in bad odour”, it is encouraging that the business cases for transport investment are receiving more attention from the wider economics profession in New Zealand. I’d certainly encourage Boyle and Hill to pursue this new found interest further, and would welcome them scrutinising the business cases for RoNS projects, many of which cost in the billions of dollars and start with BCRs less than 2.0. That’s really where the real money is being spent, and it’s where the economic evidence is the weakest.

Why are we building dangerous intersections?

Two stories have recently caught my attention for the appalling treatment of people using roads who are not in cars.

The first was a few days ago from the local paper that covers the Hibiscus Coast and details the issues with a relatively new intersection that people keep running red lights at. It’s so bad parents are making kids waive silly flags as they cross the road.

It is only a matter of time before a child is killed at a dangerous Auckland intersection where up to 14 drivers a morning run red lights, concerned parents say.

There are four schools and a preschool near the four-way intersection at Millwater Parkway and Bankside Road, and near misses are a daily occurrence, the mums and dads say.

Silverdale School parents are so worried they have been doing surveys of the intersection, counting up to 14 red light runners a morning.

The group mans the site each school day for 30 minutes wearing high-visibility vests and handing out orange flags to children crossing the road in an effort to keep them safe.

The situation came to a head in the week before the school holidays when two cars crashed in the middle of the intersection, coordinator Penny Howard says.

“It was at 8.20 am when one car obviously ran a red and hit an oncoming car. Shrapnel was sent flying across the road. Thankfully a pedestrian wasn’t hit by it.”

Yes there are bad drivers out there but 14 red light runners a morning it suggests that perhaps there’s also a design issue with the intersection and surrounding area. I suspect one of the issues is the large empty fields on two of the corners plus having the school effectively set back behind a row of trees and a large berm are contributing to giving drivers visual cues that this is an area they can travel faster. I’d be interested to know from readers what options they think would help make the area safer and more kid friendly.

Millwater Dangerious intersection

On a related note, why the hell are we still allowing roads like this to be built without dedicated cycling facilities. It wouldn’t have taken much to add them when the road was being constructed but now it’s likely to be an expensive and difficult retrofit job.

The second example is from Hamilton where the NZTA yesterday announced plans to spend $2 million upgrading the intersection of SH1 and SH26. Despite the state highway designations the area is thoroughly in a residential area with houses, shops and a school all nearby.

The Hillcrest roundabout will be replaced with a new, larger roundabout which will have three entry lanes for city bound State Highway 1 traffic and a slip lane for vehicles heading onto State Highway 26 (Morrinsville Road).

The Transport Agency’s Waikato Highways Manager, Kaye Clark says the new roundabout will improve safety and help to ease congestion at the intersection.

“The Hillcrest roundabout is the city’s busiest with 37,000 vehicles using it every day,” she says.

“At peak times it is a major pinch point which we know causes a lot of frustration for people travelling through.

“The new, larger roundabout will make a difference to traffic flow.”

Mrs Clark says the Transport Agency investigated all possible improvements for the intersection, including traffic lights.

“We looked at installing traffic lights with a pedestrian crossing however our modelling showed this would have added to the congestion issues and caused more delays,” she says.

“More lanes would have been required to get traffic through as well as the larger roundabout will and having a signalised pedestrian crossing on a section of SH1 with such a heavy traffic flow would have caused significantly more congestion.

“We are confident that expanding the roundabout is the most balanced and effective solution possible here.”

As part of the project the Transport Agency plans to improve safety for pedestrians and cyclists by building new paths and a new pedestrian crossing on SH26, so people can cross the road safely.

“With high traffic areas like this pedestrians and cyclists are safer on separated facilities,” Ms Clark says.

“We plan to build new paths on both sides of the entrance to the shopping centre and a new pedestrian crossing on SH26 (Morrinsville Road). The pedestrian crossing will have a raised refuge, so pedestrian can safely cross one lane and wait in the middle of the road before crossing the next lane.

“An existing underpass that takes pedestrians under SH1 will remain in place and a cycle lane will be formed from SH1 into SH26 giving both pedestrians and cyclists safe options to get around.”

Despite what they say it’s pretty clear the only thing the NZTA engineers cared about was the movement of cars and the intersection gives a giant middle finger to anyone not in a car. On the SH26 branch pedestrians have to either cross multiple lanes of traffic to reach the ‘refuge’. That’s may be fine for many people but what about those who can’t run such as the elderly or those with disabilities and would the designers let their children cross there? On the southern side of the SH1 branch the option is a likely dingy underpass that most people will probably ignore – like they clearly do now giving the number of desire lines through the planted median that are visible.

Hamilton SH1 -SH26 upgrade

I wonder how many parents let their children walk let alone cycle to that school.

Below is an example of one of the existing desire lines through the planted median and angled to just avoid the pedestrian barrier. I expect pedestrians will continue to prefer this more risky crossing than the pedestrian underpass a few meters away.

Hamilton SH1 desireline

To make matters traffic volumes through this intersection will likely drop in the near future as early next year the NZTA expect work to start on the Hamilton section of the Waikato Expressway which will see SH1 diverted to the east of Hamilton and away from this intersection. That is expected to be completed in 2019 and is shown below (and even by 2041 is expected to have remarkably low traffic volumes.

hamilton-2041volumes

What they’re proposing is obscene in an urban environment and will almost certainly have to be redone again in a few years time into a form that isn’t so hostile to people.

What’s happening to Takapu Valley?

As Peter found when covering the Ministry of Transport’s review of capital spending on roads (parts 1, 2, 3, and 4) our multibillion dollar national transport budget is being spent in some bizarre ways. Money’s being allocated to major roading projects that don’t offer many economic benefits in return.

MoT state highway BCRs 2005-2012

While the high-level picture is clear, it’s not always obvious what’s going on in project selection. Why does the New Zealand Transport Agency (NZTA) choose one project over another? What are their processes for assessing “strategic fit” and other considerations?

Some smart people have been taking a critical look at a major Wellington road project that’s been flying under the radar: the Petone-to-Grenada motorway. Like the Transmission Gully motorway, it’s being touted less for its benefit-cost ratio than for its impacts on the “resilience” of the Wellington region.

Tamara Duran, who writes on the Takapu Valley website, provides a useful summary of the project… and the issues with the project. In addition to her extensive analysis of the the impacts of the project on resilience (parts 1, 2, and 3), she’s put together a primer on the project, complete with maps for the out-of-towners:

Since the Christchurch and Tōhoku earthquakes, “resilience” has been the mantra of… pretty much anyone building anything, be it a building, a corporate structure, or a communications network. We all want to be resilient, to survive whatever has just happened and get back up and about our normal business as quickly as possible.

The New Zealand Transport Agency has picked up on how keen everyone is on resilience, and so is now including it in all of their sales material. Perhaps unsurprisingly, NZTA has defined “resilience” from a transport perspective as “more roads”. Not “more transport options”, and not even really “better roads”, just more. Got congestion problems? Build another road to get around it. Got a road falling apart? Build another road to take traffic off it.

Case in point: The Petone to Grenada link road, in Wellington. This road has been in the investigation and planning stages for a good 20 years now, the reason being Wellington’s notoriously challenging geography. To get from the CBD to the rest of the Region (and ultimately the rest of the North Island), there are essentially two routes out – SH1 up Ngauranga Gorge, and SH2 along the harbour.   Both of those are through narrow corridors with few or no alternatives.

P2G map 1

Source: Google Maps

The logical thing to do, then, as proposed in various studies since about 1991, is something like this:

P2G map 2

Source: Google Maps

Traffic wanting to get between the SH1 corridor in the west and the SH2 corridor in the east can “cut the corner” of Ngauranga, taking pressure off those two chokepoints.

If there’s a truck flipped in Ngauranga Gorge, traffic can go up SH2 and across P2G. Likewise if there’s a crash along SH2 traffic can go up SH1 and across P2G back to Petone. All good, and everyone’s back about their business with minimal fuss.

But 7km of road is Not Enough Road. More Road = More Resilient, remember. So what NZTA is proposing is this:

P2G map 3

Source: NZTA Presentation to Chief Executives Group, November 2014, released under OIA

We’ll turn the whole thing north-south (because clearly a north-south road is how you solve an east-west problem); then we have room to double the length. Here are some other “resilient” features:

  • Motorway to motorway interchanges through chains of roundabouts!
Source: NZTA/Opus

Source: NZTA/Opus

  • Motorway to motorway interchanges via two-lane local streets! (and roundabouts!)
Source: NZTA Petone to Grenada Project website

Source: NZTA Petone to Grenada Project website

  • “Bypasses” with one-way ramps that force you 12km out of your way!
P2G map 6

Source: Petone to Grenada Scoping Report, February 2014

  • Motorways next to other motorways! (More Roads = More Resilient!)
Source: NZTA Petone to Grenada Project website

Source: NZTA Petone to Grenada Project website

  • Roads on unstudied active fault lines!
Source: GNS Active Faults database

Source: GNS Active Faults database

  • 80 meter deep canyons through the Wellington Fault Scarp!
Source: HC8/9, Grenada-Petone Link and SH58 Upgrade Economics, Sinclair Knight Merz, April 2010, released under OIA

Source: HC8/9, Grenada-Petone Link and SH58 Upgrade Economics, Sinclair Knight Merz, April 2010, released under OIA

  • In Petone!
Source: Petone to Grenada Link Road Preliminary Geotechnical Appraisal, September 2013, released under OIA

Source: Petone to Grenada Link Road Preliminary Geotechnical Appraisal, September 2013, released under OIA

NZTA has taken a reasonable solution to Wellington network resilience woes and “made it better”, in the process negating the very function the road was originally supposed to serve. In the meantime, genuine improvements to the earthquake and natural hazard resilience of the roading network are left to languish.

Source: (ex. labels) Wellington Region Road Network Earthquake Resilience Study, Opus, August 2012

Source: (ex. labels) Wellington Region Road Network Earthquake Resilience Study, Opus, August 2012

I’d really recommend reading her entire series on the motorway. It seems like NZTA is pursuing a more expensive option that delivers much worse outcomes. In particular, Tamara argues that better results could be achieved through upgrades to a few problematic bits of the existing State Highway 58.

Meanwhile, University of Auckland statistician Thomas Lumley (who writes the excellent StatsChat blog) has been digging into NZTA’s options assessments on the project. He’s found that the agency has made some basic statistical errors in its weighting of evaluation criteria. The effect seems to have been that NZTA’s chosen the wrong project, for the wrong reasons:

If you have to make a decision with several options, each with different types of positive and negative effects, it’s going to be hard. Techniques for breaking down complex decisions into sets of simpler questions are very valuable, but it’s important that the way you break down the problem and recombine the answers fits with how you answer the simpler questions.

I’ve been pointed to what looks like an unfortunate example from the NZTA, in assessing options for the Petone–Grenada link road to be constructed near Wellington. The road comes in two sections: from Petone to the eastern section of Lincolnshire Farm, and from there to Grenada. According to the scoping report (PDF), these can be decided independently of each other, so there’s an ideal opportunity to simplify the decision making.  NZTA describes four options P1 to P4 for the first section, and four options A to D for the second section.

I would have expected them to just make independent recommendations for the two sections, but what they actually did was more complicated. First, they looked at the P options and decided based on four criteria that P4 was best.  They then looked at A+P4, B+P4, C+P4, and D+P4 for the same four criteria, and said in a footnote (p172) “Upon combining one of Option P1, P2, P3 or P4 with one Option A, B, C or D the effect more towards the negative takes precedence.

This can only make sense if the harms or benefits weren’t independent.  Sometimes that’s possible. In particular, one of the criteria was “resilience”, and you might argue that it doesn’t matter how robust the second part of the road is when the first part is under several meters of rock and mud, or filled with bumper-to-bumper traffic jams. It could make sense to take the worst value of the two sections when assessing resilience: but people who know more about Wellington-area transport than I do still seem dubious.

The same argument certainly doesn’t apply for the other criteria: archaeological,  ecological,  landscape/visual impact, and transport benefit/cost. If one section of the road is an environmental nightmare, that doesn’t make the environmental impact of the other section unimportant. If one section of the road is unavoidably ugly, that doesn’t excuse making the other section ugly. If one section destroys an important heritage site, it doesn’t mean the other section doesn’t have to care about preservation of the past. If one section is ridiculously expensive it doesn’t mean the costs are unimportant for the other section.

The impact of decomposing and recombining the evaluation as they did, is that any criterion where P4 was bad becomes much less important in choosing among options A to D. P4 was very bad on the landscape/visual criterion, and moderately bad on ecology.

By now you should be expecting the punch line: evaluated independently, options A and B look good because they score well on ecology and landscape/visual criteria. Evaluated in combination with P4, they look terrible, because the ecology and landscape benefits are masked by the “more negative” combining rule. That’s a problem with the combining rule, not with the road. Here’s a colour-coded version of the information in Table 23-19, p182 (from T. Duran)

P2G separate and combined option assessment

Not only is the combining rule obviously missing some information, it’s not even internally consistent. If the evaluation had been done in the opposite order they might well have chosen A first, and then looked at A+P1 to A+P4. Even D was what they’d chosen first, P3+D would then look slightly better than P4+D.

It’s very tempting to look for ways of combining preferences that don’t rely on numbers, just on orderings, but in most cases they aren’t available, and attempts to do it leave you worse off than before.

This evaluation wasn’t set up to focus only on resilience — even assuming that the resilience assessment is valid, which I hear is also being questioned — it was set up to value the four criteria equally. It really looks as though a minor detail of the approach to simplifying the evaluation has had a large, accidental effect on the result.

Thomas’s words are gentle but suggest serious methodological errors in NZTA’s project selection. Taken together with Tamara’s critique of the agency’s evaluation of the resilience impacts of the Petone-to-Grenada road, it really makes you wonder what’s wrong with NZTA’s decision-making.

A Wider motorway

This image came up the other day on the NZTA’s Facebook page and it highlights just how much wider SH16 will be between Te Atatu Rd (top) and Lincoln Rd when the works have finished. Before they started work the motorway was just two lanes wide each way. When finished it will be four lanes wide comprising of three general traffic lanes and a bus shoulder lane each way.

Lincoln Rd to Te Atatu April 15

The stages of construction are shown in this diagram below

Lincoln Rd to Te Atatu Plan

The corridor could get even wider as the North West busway is planned to be on the south side of the motorway

Busway schematic

Additional Harbour Crossing back on agenda

The government has announced it is restarting the process to protect the route for an a third harbour crossing that raises a huge number of questions.

New Waitemata Harbour crossing future proofed

Minister of Transport, Simon Bridges, has taken steps to future-proof the route for an additional Waitemata Harbour crossing in view of the rapid growth Auckland is set to undergo in the next 20 years.

“I have asked the NZ Transport Agency to recommence work on what will be a critical transport link for Auckland and the upper North Island.

“The preferred route for the additional crossing is a tunnel east of the Auckland Harbour Bridge between the Esmonde Road interchange on the North Shore, and Victoria Park Tunnel and Central Motorway Junction in central Auckland.

“Advisors are preparing for the designation process and are putting together a business case focusing on the timing of construction and potential funding options,” Mr Bridges says.

In 2013 the Government announced its support for a tunnel in preference to a bridge.

“With increasing demands on Auckland’s transport network, the Government will continue to work closely with its local government partners to provide a resilient network and wider transport choices,” Mr Bridges says.

The NZ Transport Agency says an additional crossing is likely to cost between $4 billion and $6 billion, and is likely to be needed between 2025 and 2030. A construction start date will depend on a number of factors, including the rate of freight and traffic growth.

Mr Bridges says that the additional Waitemata Harbour crossing will work in conjunction with the existing Auckland Harbour Bridge.

The business case will look at a range of public transport options, including heavy rail. The NZ Transport Agency and Auckland Transport will be working together on this part of the project, including any necessary route protection for public transport.

“The Government knows that investment in all modes of transport will ease congestion and bring lasting benefits for Auckland and for New Zealand as a whole,” Mr Bridges says.

The NZTA last studied an additional crossing five years ago and the reports from that study are available here. The questions I have are in no particular order.

With construction depending on factors such as traffic growth, will the new business case take into account the actual traffic volumes from the last 8+ years. After almost 50 years on constant increases, traffic volumes fell after 2006 and have been so stubbornly flat that they are still less than they were in 2003. Not only did the previous business case – produced in 2010 – predict growth that hasn’t materialised but they also used a model to predict the volume for the starting year of their prediction (2008) which was well above the observed actual volumes.

AHB Volumes

Related, what will be the employment and traffic volume targets the project must achieve. After all if the City Rail Link is going to have bogus targets foist upon it then why shouldn’t the single most expensive project we’ve ever considered.

With the project costing between $4 and $6 billion how will we pay for it. To put things in perspective we currently spend about $3.4 billion on transport per year for the entire nation and that includes costs for state highways, NZTA contributions towards local roads, road policing, and of course NZTA contributions towards public transport. Within that budget we spend $1 to $1.4 billion on state highway improvements. In short an AWHC would suck up massive amounts of cash and that would impact on a huge numbers of projects from all around the country. Even if built as a PPP the ongoing payments would likely cripple our transport budgets for decades. As an example Transmission Gully which is costing around $850 million will have repayments once it opens of about $125 million a year. AWHC would be significantly more than that.

Will the business case achieve a Benefit Cost Ratio of greater than the 0.3 it did last time (Answer: presumably it will because of the changes since then to the NZTA’s Economic Evaluation Model allowing for a longer assessment period and reduced discount rate – still won’t be above 1 though)

AWHC 2010 BCR

It’s all very well talking about a horrifically expensive tunnel under the harbour but what constantly seems to be ignored is what happens on either end of the tunnel. Studies prior to the 2010 one have talked about how any new crossing would also require major expansions to the Northern Motorway to cope with the increased capacity thrown at. How much is it going to cost to duplicate SH1 to Albany and beyond? If not then we just get this situation.

WestConnex

What impact will the $4 billion we’ve been spending to create the Western Ring Route have on traffic and travel behaviour. At the very least we should probably be waiting till after that work is completed and traffic volumes have settled down before we do any analysis of traffic demand over the harbour.

WRR project location

Regardless of how much it costs or what the benefits are one fact that can’t be ignored is that this project will have major impacts on the environment it passes through. It effectively creates a new motorway out in Shoal Bay with all the red hatched parts in the images below being reclamation and the blue parts being viaducts. I wonder what the likes of the Herald’s John Roughan will say about – note:  I still don’t think he’s admitted he was wrong about the Northern Busway.

AWHC north of Onewa AWHC Sulhur Beach

Further if some of the residents of Northcote got so upset about the idea of Skypath, I wonder what they’ll think of having a mini spaghetti junction on their doorstep. Even more so when they realise that the two square boxes on the image above where the new lanes change from tan to purple colour (to the right of the 1 symbol) are 35m high (~10 storey) ventilation stacks for the exhaust fumes inside the tunnel. There is also one on the city side next to the current Air NZ building (below).

AWHC Westhaven

One mini positive is that the government are at least saying the business case will consider a rail crossing however in my mind the NZTA also need to assess options that involve building a PT only crossing first. A dedicated PT crossing along with Skypath are the real missing modes across the harbour. This is especially important given the huge growth we’re seeing in bus passengers from the shore and in the morning we’re seeing up to 30-40% of people crossing on a bus – up from 18% in 2001. This growth in PT is likely to continue for some time yet, especially once the new network eventually makes PT much more useful to a wider variety of people. One risk is I suspect there are quite a few people behind the scenes that will think an acceptable solution to PT across the harbour is just to leave it on the existing bridge.

Car and Bus trips across AHB

The 2010 and 2011 car results seem like they could be incorrect but I can’t confirm it

 

Overall route protection itself isn’t a bad thing but any suggestion that this is project is needed any time soon is fanciful thinking. There are far greater priorities in Auckland such as the CRL and significant upgrades to PT in many other areas. The government should be focusing on getting those projects consented and underway first.

Northern Express delays on the way?

The NZTA have announced works that should result in an improved experience for bus users from north of Constellation Busway Station but that while it’s constructed is likely to cause delays to both bus users and car/truck drivers.

North Shore commuters are advised to allow additional journey time as work starts on the upgrade of the citybound shoulder lane on State Highway 1 leading to the Upper Harbour Highway (Constellation Drive) exit.

The temporary motorway shoulder lane closure, citybound between Greville Road and the Upper Harbour Highway, will be in place for 10 weeks, while the shoulder is widened to take buses continuously between the two interchanges.

Providing a continuous bus shoulder between Greville Road and the Upper Harbour Highway off-ramp will mean citybound buses no longer have to merge in and out of traffic lanes heading to the Constellation Park and Ride,” says NZ Transport Agency’s Acting Auckland and Northland Highway Manager Mieszko Iwaskow.

“These improvements, along with the upgrade of the Greville Road interchange, and the additional northbound lane between Upper Harbour Highway and Greville Road, will provide better journey time reliability for those travelling along the Northern Motorway.”

Due to be completed in June, the shoulder widening is the final stage of the Upper Harbour Highway to Greville Road Northbound Three-Laning Project, which is part of the Northern Corridor Improvements Programme.

For further information please visit www.nzta.govt.nz/UHH-Greville, or call 0800 72 74 74.

For Northern Corridor Improvements, please visit www.nzta.govt.nz/projects/auckland-northern-corridor/ or the Project Information Hub located at 33A Apollo Drive, Rosedale.

image002

While the outcome should certainly be an improvement I do worry about the impact this work will have on bus reliability, especially with it starting in the middle of March.

Now if only they’d build a full busway instead of our at least as part of the massive interchange they have planned.