Radical Transport

Keep New Zealand Real

2011-05-11T19:16:00.000-07:00

I've decided to replace this blog with a new one building on the themes I developed in my book, From Smoke to Mirrors.
Check out my Keep New Zealand Real blog over at kevincudby.com.
This blog will be discontinued when I get a round to it.

Converting Coal Into Liquid Fuels Is Dumb

2010-05-09T17:19:00.000-07:00

A proposal to convert South Island lignite (coal) into liquid fuels is bouncing around the 'net.
This is a dumb idea.
Replacing only a third of our conventional fuels with FT synthetic fuels made from lignite would increase New Zealand's greenhouse gas emissions by more than 25 percent*. That's because coal-to-liquid facilities emit lots of carbon dioxide. That is on top of the greenhouse gas emissions from engines, which are practically identical for conventional fuel, and for fuel made from coal.
Coal to liquid fuel will increase the carbon footprint of all New Zealand exports, including agricultural products and tourism. And that, in turn, would hurt our economy.

Synthetic Fuel Production
Coal promoters have been hyping up a coal-to-liquid (CTL) facility in the South Island for several years. They point out that this would satisfy New Zealand's diesel requirements.
The only proven way of making fuel suitable for modern diesel engines is the Fischer-Tropsch synthesis process. Although there are other ways of making coal into liquid fuels, we can safely assume this is what they are talking about.
The Fischer-Tropsch process can convert various raw materials into high-quality liquid fuels (petrol, diesel, jet fuel). The quality of the finished product depends on the characteristics of the Fischer-Tropsch (FT) synthesiser, but not upon the raw material. However, the impact of carbon dioxide emissions from FT fuels depends on the raw material. Made from wood, they are carbon-neutral and will not affect the global climate.
Coal is a fossil fuel, which means that FT fuels made from coal will exacerbate global warming. There are no ifs, buts, or maybes about that.
Based on published information, we know that FT diesel is practically a drop-in replacement for present-day diesel. We also know that lighter FT hydrocarbons, known as naphtha, can be upgraded into good quality petrol.
If the proposed CTL facility were designed to focus on diesel, it would inevitably produce naphtha as a byproduct. This would account for about 20% of its output (on an energy basis).
New Zealand consumes roughly equal quantities of petrol and diesel, so we can be quite certain that the New Zealand fuel market can absorb all the CTL naphtha this hypothetical coal-fed diesel factory can make.

Greenhouse Gas Emissions
In 2007, New Zealand's greenhouse gas emissions totaled 75.55 million tonnes (CO2-e), excluding the absorption of greenhouse gases by growing forests and land-use changes. If we take into account the effect of land use, land use changes, and forests, the total was 51.71 million tonnes (CO2-e).
Of that, 7.759 million tonnes resulted from diesel consumption.
Suppose we used CTL diesel instead of conventional diesel.
Based on the results of a 2008 analysis by New Zealand scientists**, I calculate we would have emitted 18.59 million tonnes (CO2-e) from CTL diesel (10.75 million tonnes more than ordinary diesel)
It doesn't end there.
In the process of converting CTL naphtha into petrol and burning it up in our engines, we would have produced an extra 2.63 million tonnes, compared with ordinary petrol.
Overall, CTL fuels would have produced an extra 13.38 million tonnes.
Excluding LULUCF, our greenhouse gas emissions would increase by 17.7 percent.
Overall, converting lignite into CTL fuels would increase total greenhouse emissions by more than 25 percent.

Agricultural Greenhouse Gas Emissions
Agriculture accounts for 12 percent of New Zealand's diesel consumption. CTL diesel would directly increase agricultural greenhouse emissions by about 3.5 percent.
But.
Agricultural products are useless until they have been transported to markets. That requires diesel. The carbon footprints of our agricultural exports would grow by more than 3.5 percent.

Can't We Bury It?
No.
So-called carbon capture and sequestration (CCS) systems take carbon dioxide from the factory smoke-stack and pump it into the ground. This can only work if the ground happens to contain a suitable geological structure, such as a worked-out gas field. We don't know if Central Otago's underground structures can safely hold all this carbon dioxide. There's no point spending a lot of money and energy pumping it into the ground if it leaks out within a few years or decades.
CCS increases operating costs. If it were added to the proposed CTL facility, we would quite likely find that CTL fuels end up costing more than carbon-neutral FT fuels made from wood chips.
Unless coal promoters can point to an existing CTL facility with fully-functional CCS technology, I will not believe they have any intention of installing CCS technology on their proposed facility. To do so would involve developing new technology.
Even if someone does successfully invent CCS technology, coal promoters would need to demonstrate that the carbon dioxide will remain underground until the onset of the next ice age, in about 30,000 years, before I will accept that CCS technology can reduce anthropogenic climate change.
That will take, oh, I'd say about 20,000 years of practical testing and monitoring.

The Real Impact
British and European consumers are already avoiding products with large carbon footprints. CTL liquid fuels boost the carbon footprints of all New Zealand exports, making our products less attractive to foreign consumers. We will lose sales. We can be quite certain of that.
Farmers will quite likely respond by cutting production: either intentionally, in response to falling sales; or accidentally, when they go broke.

Is that what we want?

--
* Updated to take account of LULUCF, 4 June 2010
** Hall & Jack, 2008: Hall, Peter; & Michael Jack: Bioenergy Options for New Zealand – Pathways analysis. Rotorua, NZ: Scion, 2008. http://www.scionresearch.com/bioenergy+report.aspx, visited 20 Oct 2008.

Can Wellington Depend on Road Transport Indefinitely?

2010-01-25T00:30:00.000-08:00

Some economists say that because humanity has always found new technologies, we will continue to do so. According to this perspective, economic growth can continue indefinitely.
Commonsense and the laws of thermodynamics suggest that exponential growth cannot go on forever. For example, fusion is sometimes promoted as a limitless source of clean energy. However, we will not see a self-supporting fusion reactor before 2030 at the very earliest. We won’t be able to realistically assess the technology’s potential until this first small-scale experiment is complete, and even then, there's no guarantee it will work. We might find it necessary to build another experimental reactor, which will take another twenty-odd years, before we can realistically make a judgement. In my opinion, it would be extremely unwise to make any plans based on this technology until 2050 at the very earliest. There's no basis for the idea that it will not be subject to some kind of constraint.
A contrary view is that road and air transport are not sustainable, because fossil fuels are finite, and because their consumption causes climate change, and because we have not yet commercialised suitable alternatives.
Extremist Perpsectives are Unrealistic
There's no reason to think that road transport will necessarily be constrained by energy shortages, or that its impact on climate change cannot be neutralised. Engineers know how to make renewable, carbon-neutral petrol, diesel, and jet fuel. Some of the necessary technologies are still being commercialised, but no new inventions are required.
It's also worth keeping in mind that present-day cars, trucks, buses, trains, aeroplanes, and ships are built mostly from readily recycled materials such as steel and aluminium.
The odd technological breakthrough might improve matters, but the world will not be forced to abandon motorised road transport if they don't happen. The same goes for aviation and shipping.
I’ve spent a good part of the last three years surveying the strengths and weaknesses of various carbon-neutral and carbon-free technologies. I've identified a raft of excellent technologies seldom mentioned in mainstream NZ media. After analysing their strengths and weaknesses, I’ve reached the following conclusions:

It is very unlikely that global supplies of petrol, diesel, jet fuel, fuel oil, and other hydrocarbon products will taper off when crude oil production starts winding down. We have plenty other other ways of making these
products.
Even if the world is forced to use an alternative road transport technology, energy will not be the constraint. The world can continue to support present levels of land, air, and sea transport using a mix of renewable fuels and well-proven alternative technologies. There is room for a small amount of growth, but not much.
New Zealand scientists and engineers know how to satisfy local transport requirements with carbon-neutral petrol, diesel, jet fuel, and fuel oil, made from renewable indigenous resources. Unlike the rest of the world, we already know we do not need alternative road transport technology such as ethanol, hydrogen, or batteries. The necessary technology has already passed the high-risk laboratory and pilot-scale development phases. We can expect it to be commercially mature within the next decade.

Later this year I’ll write about these future transport technologies. For the moment, my main concern is that Wellington’s transport infrastructure is being shaped by an inappropriate debate. On one side is the belief that roads will eventually become redundant. On the other side, the belief that our roading system can expand indefinitely. Both positions are wrong.
Both sides must accept that their opponents may have some worthwhile points to make. Wellington is very much a work in progress. It emerged from a series of historical accidents and the city was built by people trying to make the best of various unplanned situations. It has never had an effective land transport system. Its street layout is, at best, an ad hoc shambles, and it is getting worse.
Better Communication Can Lead to Genuine Improvements
Right now, Wellingtonians are talking past each other, and this lack of genuine communication is ruining our city.
Karo Drive exemplifies the problem. As far as I can tell, roading opponents wanted two things: They wanted uninterrupted pedestrian flow from the Aro Valley down through Cuba Street (and perhaps Willis Street) to the CBD; and they wanted the heritage neighbourhood to be preserved.
The purpose of the new road was to provide an unimpeded route for through traffic, bypassing the CBD.
Clearly, both of these results could have been achieved by building a four or six-lane tunnel from Willis Street to Taranaki Street, with the road then running alongside Buckle Street to the Basin Reserve.
Engineers would prefer to build such a tunnel by the "cut-and-cover" technique. That is, they dig a trench for the road, and then roof it over. They would have needed to move all the existing buildings, build the tunnel, and then restore the neighbourhood.
The original plan called for a trench.
Instead of calling for it to be converted into a tunnel, with restoration of the neighbourhood, objectors decided to fight the whole idea of a road. The upshot? Upper Cuba Street is divided in two by a very busy street, a bunch of very nice heritage buildings have been plonked into a fake heritage precinct that no-one uses, and Wellington still does not have a decent through road.
Some parts of the project can be salvaged, but for the money, we could have done a lot better if the various groups had communicated better.
Energy is not the Constraint
There is no technical reason why transportation should be constrained by the supply of carbon-neutral renewable energy. Oil producers would very much like us to believe there is, because if we think there's a looming energy crisis, we'll stoically allow them to rip us off.
In my opinion, humanity will quite likely encounter other constraints, such as possible shortages of minerals and water. Neglecting Wellington's transport infrastructure cannot, in any way, mitigate those problems.
In my next instalment, I'll write about the ways that Wellington can develop its road and rail systems to complement each other, preserving the things that make Wellington special, and eliminating the blockages that throttle its economy and make life difficult and stressful for tradespeople, transport operators, and
other folk who spend part or all of their workday using Wellington's roads.

Merry Christmas

2009-12-23T21:04:00.000-08:00

If you're looking for positive practical thinking about carbon-neutral transport and liquid fuels for Wellington in particular, and New Zealand in general, you won't want to miss this blog in 2010.
Have a great holiday.

What a Difference!

2009-12-10T18:57:00.000-08:00

I usually plan my workday to avoid commuter traffic. If I spend all day in Wellington I use the trains, and I try to schedule short meetings outside rush-hour.
Wednesday was an exception. For the first time in months I've been forced to drive along the Western Hutt Road during rush-hour.
I left Oriental Bay at 5 p.m. The trip along the waterfront and the motorway to Ngauranga was typically slow but tolerable. But what a difference when I reached Petone. Gone where those infuriating Korokoro and Maungaraki queues. The traffic flowed so smoothly it felt like normal weekday traffic and far better than the madness of a typical weekend.
Congratulations to everyone involved in the Dowse to Petone upgrade. The widened road through Petone, the grade-separated interchange at Maungaraki, and the continuous median barrier have dramatically transformed the road. If commuters use the trains whenever possible, business travelers and transport operators will be able to rely on getting around Wellington Harbour without resorting to helicopters, even at peak times.
Needless to say, the job is far from complete. We desperately need new trains, otherwise commuters will start buying battery powered cars or plug-in hybrids. If that happens, we'll discover the true meaning of congestion and high electricity prices, not to mention all the greenhouse emissions associated with making all those batteries.
About a third of all the traffic that uses the Western Hutt Road is commuter traffic. That's a lot of traffic to cram into a short period at the beginning and end of each day, which is why the road gets so congested at peak times.
However, it struggles to cope with normal business-day traffic, which is the main reason it needs improving. It's never been any good and we should have made it into a motorway forty years ago.
Melling is a shambles. Belmont's b*** awful, and Kelson is chronic. We need grade separated interchanges at Kelson and Melling. We need a two-lane slip road to link the other side roads to these grade-separated interchanges and eliminate intermediate intersections. We should also extend the Melling railway to Kelson, so that it can take as much commuter traffic as possible from Lower Hutt's Western Hills.
And, as I mentioned in my previous post, we absolutely must fix the cycle road. I notice another crappy "cycle-track" is being built at Petone. We must stop wasting money on these ridiculous white elephants and do a proper job.
Before we start on any of this we should commission a traffic study of the Akatarawa Motorway to find out if we can get away with four lanes between Maungaraki and Silverstream. We might need to six-lane this section (though I suspect we'll get away with four lanes if slow drivers learn to drive in the left lane instead of driving two abreast in their three tonne diesel-hybrid SUVs).
None of this detracts from the fine effort that has gone into the Dowse Interchange. I won't say it's perfect but it's damn good, it looks to me as if the road can be widened to six-lanes if necessary, and it has eliminated some very serious congestion.

How to Build a Decent Cycle Road Between Petone and Ngauranga

2009-11-26T20:00:00.000-08:00

As long as I can remember (which goes back to the early 1960s) cyclists have been riding along the Western Hutt Road's stopping shoulders.
There has always been a "cycle-track" between the road and the railway, and it has always been totally useless for regular cycle commuting, mainly because of its poor geometry. Not too long ago a shipload of money was spent on this white elephant, but cyclists are still forced to ride on along the stopping shoulders, because the "cycle-track" is too dangerous.
I've ridden along the stopping shoulders myself. I've also done a fair bit of cycling in other parts of New Zealand. I've cycled so many miles that most parts of my road cycle have been worn out and replaced at least once.
This experience has taught me a thing or two about the practical requirements for a decent cycle road. What I've learned fits well with readily available cycle road design handbooks, such as the UK Department of Transport booklet, "Cycle Infrastructure Design".
The most important point is that cycle commuting is only practical if the cyclist can maintain a reasonably high speed, typically at least 25 kph for an hour, or 30 kph for a shorter commute. To do this safely, the cycle road must satisfy certain requirements, most importantly, lane width, curve radii, and visibility around curves. One of the main reasons I will not use the existing Petone to Ngauranga "cycle-track" is that it does not satisfy these requirements. Some curves are so narrow and tight that if you meet someone coming from the opposite direction you will crash. No ifs or buts. You'll go head-on into another cyclist at a combined speed of about 50-60 kph. Not pretty.
I feel safer riding on the stopping shoulder. A car driver would need to go out of their way to intentionally run you down. I've had the odd car driver swerve to the left to "buzz" me. That's scary, and I suspect they are taking out their frustration at the inadequate road system, which they wrongly blame on cyclists. Many of the people who oppose motorway expansion also promote cycling, so perhaps some young blokes think all cyclists would like to ban cars and trucks. If so, they are wrong-headed f***wits. Of all the cars I have owned, the one I would most like to get back behind the wheel of, was a V8 Valiant. Not all cyclists are anti-car. Some of us cycle for the fitness benefits.
I reckon the Western Hutt Road should incorporate a decent two-way cycle road suitable for cycle commuting. In Wellington, tailwinds can easily push you up to 35-40 kph. The cycle road must allow for this, with sweeping curves and wide lanes. Most importantly, it MUST be off-limits to pedestrians. Pedestrians on shared tracks are unpredictable, they tend to step into your path just as you pass them. I've crashed badly more than once avoiding pedestrians on shared tracks and still have the scars to prove it. I swore off shared cycle/pedestrian tracks more than ten years ago.
The absolute minimum width for a two-lane cycle road is about four metres (two metres north-bound, two south-bound). It should also include a stopping shoulder wide enough for people to stop for a breather, or to change tyres.
Adequate maintenance is vital. Only a concrete barrier separates the cycle road from the motorway, so a bottle chucked out of a passing car can land on the cycle road. It only takes one cheeky little shit to chuck a Heinie bottle out of their window to create a serious hazard on the cycle road. The Western Hutt Road is so busy that the chance of this happening, at least once a week, is pretty-much one hundred percent. That is why the cycle road should be regularly cleaned by a street-sweeping machine. This means the cycle road should be wide enough to allow a cyclist to comfortably pass the street-sweeping machine. I suspect most cyclists will be happy with a four metre road plus a one metre stopping shoulder, provided the street sweeper is no more than about 1.8 metres wide.
Another important requirement is that roading authorities should treat cycle roads as seriously as they treat other roads. Which is why I call them cycle roads, not cycle-tracks.
We can convert the existing left-hand north-bound lane of the Western Hutt Road between Ngauranga and Petone into an excellent cycle road. This would provide a two-metre wide lane in each direction, a one metre shoulder against the hill, and a 200 mm shoulder between the south-bound lane and a concrete barrier between the cycle road and the motorway.
Most of the rest of the existing road would be taken up by the three south-bound vehicle lanes. A bit of the existing stopping shoulder, and the existing "cycle-track" should be reserved for an additional railway track.
While we are at it, we might as well build a footpath along the seaward side of the railway (fenced off from the railway tracks). (As mentioned previously, the north-bound side of the motorway would run along the hillside well above the existing road.)
It's very simple to connect this cycle road into the rest of the roading system.
At Ngauranga, the ramp carrying the north-bound lanes up onto the hill-side would fly over the cycleway, which would run alongside the motorway to the intersection of Centennial Highway and the Western Hutt Road (at the bottom of the Ngauranga Gorge).
At Petone, the north-bound carriageway would cross a flyover that carries it down to ground level near Cornish Street. The cycle road would run under this flyover, emerging on the western side of the motorway, and climb up to the Korokoro bridge which carries it across the railway and onto the Main Hutt Road.
This completely separates cycle traffic and motorised traffic between Petone and Ngauranga.

Decongesting Ngauranga

2009-11-12T20:44:00.000-08:00

The Akatarawa Motorway opens the way for a radical re-organisation of freight transport in the Wellington region.
Right now, just about everything must travel through either the Ngauranga Gorge, or the Wellington Motorway, or both.
Very little freight travels into or out of the region by rail, because very few freight forwarders possess depots that allow them to efficiently transfer freight between trains and local delivery trucks.
Long-haul trucks operate from depots at places such as Ngauranga and Seaview. Many of them use the Ngauranga Gorge every day. On top of all that long-haul traffic, local delivery trucks and vans operate from the same locations. Those serving areas along State Highway One, from Tawa to Waikanae, further increase traffic in the gorge. Other local delivery trucks radiate out from Ngauranga and Seaview along the already-congested Wellington Motorway.
We can reduce inner-city traffic by locating freight depots on the outskirts of the city. This means that only trucks and vans with freight for the inner city need to use inner city streets.
Depots for the northern suburbs would be located at Waikanae and Upper Hutt. Waikanae is especially attractive because it is on the North Island Main Trunk railway, so freight forwarding depots at Waikanae would be able to transfer freight between trains and local delivery trucks, as well as between long-haul and local delivery trucks. This would shift a significant amount of long-haul freight from road to rail.
Upper Hutt would suit freight forwarders who, for whatever reasons, cannot use rail.
Local delivery trucks would radiate out from both locations to serve areas north of Ngauranga. Organised properly, none of these trucks or vans would go anywhere near the central city, and only goods vehicles with freight for Ngauranga would use the Petone to Ngauranga motorway.
Ideally freight for the southern and western suburbs would go to depots south of the central city, to minimise congestion from that side. That requires improvements to the Ngauranga to Airport Corridor. That is outside the scope of this blog, though I should say that I see no reason we can't extend the North Island Main Trunk railway and the motorway through to the airport.
In any case, I'm convinced that the Akatarawa Motorway, combined with a six-lane motorway and a wide, two-way cycle road between between Petone and Ngauranga, will open the way for a radical revamp of Wellington's freight distribution system which would reduce congestion and make driving and cycling between the Hutt Valley and Wellington far more pleasant than it presently is.

Spoke for Wellington

2009-10-27T19:52:00.000-07:00

Cities are essential to human culture, and transport is essential to cities.
A city is, first and foremost, a hub. Without decent transport connections it is rubbish.
Transportation requires energy, in the form of liquid or gaseous fuels, or electricity, or anything else engineers can harness. My forthcoming book lays out a simple plan by which NZ can become totally self-sufficient in energy by 2040. The book does not try to predict the technological future of road transport. It surveys all the options, including batteries, hydrogen, advanced hybrids, ethanol, biodiesel, synthetic hydrocarbons ("renewable" petrol, diesel, jet fuel and fuel oil), and even pneumatic vehicles.
The underlying message is very simple: Energy is not a constraint upon the New Zealand economy. It does not matter which technology, or which mix of technologies, we deploy in our road transport system. We can produce the energy from renewable indigenous resources. For all technologies except biodiesel we can do it without reducing our agricultural exports. For all except biodiesel, and perhaps ethanol, we can eliminate liquid-fuel-related greenhouse emissions.
Make no mistake: A time will come when global oil production will begin to fall, and when that happens, a major economy could fail. We also know that if we do not move away from fossil fuels very quickly, the sea will rise faster than it is already rising, and the climate will change in ways that will very likely cause serious problems.
However, New Zealand is well-endowed with renewable energy. There is absolutely no doubt we can continue to support current levels of road transport activity, unless our society is sabotaged by road-hating Luddites.
We cannot afford to squander energy. No-one can. That's why we need to expand and upgrade our rail network. We will not eliminate the need for a decent rail network by fixing Wellington's roading problems. If you think that's what this blog is all about, you are mistaken.
The point is that State Highway One between Wellington and Levin was already outclassed when I started driving, back in the 1970s. It really is a serious embarrassment. Wellington is our capital city. This is where foreign visitors come to see our weirdest and whackiest architecture and sculpture and art, and yet the city's main connection with the rest of the North Island is complete and utter rubbish.
We should have fixed it thirty years ago. The trouble is that the options we have been offered are awful. The exit from the Ngauranga Gorge into the harbour is breathtaking, but the approach to those magnificent flyovers is horrible. At the best of times it can barely handle the traffic, and in bad weather or at busy times it quickly becomes overloaded. By the time you get to the flyovers, you're so stressed out you can't enjoy the view.
Imagine the alternative. From Peka Peka the road veers southwest and climbs gently through a wide rural basin. After cresting the summit it crosses a wide pass, and then, almost two kilometers beyond the summit, it gently descends a forested gully and sweeps into a short, curved tunnel. Bursting out of the tunnel it meanders along a flat valley floor beneath forested hills. Emerging from the forest it follows the wild meandering River Hutt. As the road sweeps down the valley the river becomes ever more civilized, reflecting the nature of the settlements along its banks. At Melling the river swings east, leaving the road to spear its way between the sheer cliffs of the Western Hills and the sheer walls of Petone's warehouse district. But it saves the best till last. Emerging from under the Korokoro bridge, the six-lane motorway soars high above railway lines and cycleway. The southbound lanes drop to ground level between the cycleway and the railway, while the northbound lanes run along a ledge carved into the hillside, traffic screened from view behind a strip of native bush.
I once heard a hitchhiker gasp as I drove out of the Ngauranga Gorge onto the flyover onto the motorway. He thought it was spectacular. The Akatarawa Motorway will be even better.

Hilly, Hillier, Hilliest

2009-10-08T23:24:00.000-07:00

Any road into or out of Wellington is going to be hilly.
There's a big difference between the three possible routes from Peka Peka to Wellington.
Two of these routes traverse the Ngauranga Gorge. This must be Wellington's most notorious road, thanks to the diabolical combination of wicked reverse camber and a very steep slope. In wet weather it is murderous.
The steep section of the Ngauranga Gorge is just over one kilometre long. It has a slope of more than 8.5 percent, which means that for every one hundred metres of horizontal travel, the road climbs (or falls) 8.5 metres.
If you live in Wellington, you’ll know it doesn't take much to cause an accident on the Ngauranga Gorge.
This road also wastes fuel, because many drivers are forced to use their brakes on their way down. If you can coast all the way down without braking, then, at least in theory, you could save enough fuel to make up for the extra fuel you needed to get up the hill in the first place.
However, if the road is too steep, then you have to use your brakes, which wastes energy warming up brake discs and brake pads.
We might improve matters by adopting vehicles with hybrid transmission systems, but I doubt that even the best hybrid systems could completely solve this problem. And of course, hybrids can't fix the safety problem.
Coastal Route
Heading south along the existing (Coastal) route from Peka Peka, the first steep section is the climb through Pukerua Bay, which reaches 83 metres above sea level. The steepest part of this climb has an eight percent slope.
The downhill section south of Pukerua Bay has a five percent slope. The rest of the route would be fairly flat, if it weren’t for the Ngauranga Gorge.
Transmission Gully
This is by far the hilliest option. From the Peka Peka end, the first steep section is the 4.5 kilometre climb from McKay’s Crossing to the Wainui Saddle, which includes two kilometres of eight percent slope. Fortunately, this will have sweeping curves, crawler lanes in both directions, and NO reverse camber. Still, if you think this part will have a 100 kph speed limit, you're dreaming. We’ll be lucky to get an 80 kph speed limit here.
The next steep bit is the climb from Pauahatanui to the James Cook Interchange behind Whitby. This has just over a kilometre of 6.5 percent, which is too steep for a motorway. And then, of course, we have the Ngauranga Gorge, which will remain the scourge of State Highway One if we build a road through Transmission Gully.
Akatarawa Motorway
This is practically flat from Peka Peka to Reikorangi (inland from Waikanae). Then it climbs up to the Menin Reiki saddle, with 3.8 kilometres of five percent slope. According to Land Transport NZ's “State Highway Geometric Design Manual” (pg. 5-3), this will be flat enough for a 120 kph speed environment.
By the way, this road is nowhere near as high as the saddle on the existing Akatarawa Road. Menin Reiki is 340-360 metres above sea level, whereas the summit of the existing Akatarawa Road is 461 metres above sea level. Fortunately, we don’t need to go there.
From the summit, the road follows the Akatarawa River down to Cloustonville, with a grade varying between three and four percent. At Cloustonville there is five hundred metres of five percent, and then from there to Wellington, the slope never exceeds three percent. You might as well call it flat.
Comparing the Options
Akatarawa is by far the flattest option, with a maximum grade of five percent. However, since it has not been surveyed in detail, this is best thought of as a theoretical possibility. The terrain looks promising but we have not yet checked it out. At the other end of the scale, Transmission Gully is by far the steepest.
Another interesting question is: Which route has the most uphill and downhill driving? We can get a simple comparison by adding up the height of all the hills: the total vertical climb. Between Peka Peka and Kaiwharawhara, the vertical climb adds up to:

Coastal: 250 metres (Pukerua Bay, Ngauranga)
Transmission Gully: 585 metres (Wainui Saddle, James Cook, miscellaneous hills, and Ngauranga)
Akatarawa: 340 metres (Menin Reiki)

Hilliness is not the only important criteria. However, it has a significant influence on safety and fuel consumption. The Akatarawa Route is a lot better than Transmission Gully. And, since it avoids the steep grades of the Ngauranga Gorge, it also beats the Coastal Route.

Wellington Needs a New Roading Plan

2009-09-24T21:37:00.000-07:00

The Transmission Gully Highway might have been a good idea half a century ago, but Wellington has outgrown it just as surely as it has outgrown the Coastal Highway.
If the goal is an unobstructed road from Peka Peka to Wellington, we should investigate a motorway through the Akatarawa Valley combined with an upgraded Western Hutt Road.
From Waikanae, the route would climb to a saddle about 2.5 km southwest of the summit of the present Akatarawa Road, then follow the Akatarawa Valley to the existing highway near Upper Hutt.
This route has gentle gradients that would allow it to become a true motorway. The steepest section, the climb from Waikanae to the summit, requires a five percent gradient, much flatter than the eight percent gradients of Transmission Gully and the Ngauranga Gorge.
The Western Hutt Road between Petone and Wellington can be upgraded by carving three new northbound lanes into the hillside above the existing road, which would become three southbound lanes and a two-way cycle track wide enough to accommodate proper road maintenance equipment.
The distance from Pekapeka to Wellington via Akatarawa is within a kilometre or so of the distance via the proposed Western Bypass, Paraparaumu, and Transmission Gully.
The existing Akatarawa Valley Road would be retained as a local access road, with no connection to the motorway except Upper Hutt, Cloustonville, and Waikanae. The summit would have a grade-separated intersection providing access to the ridge-top tracks.
(also posted on Stuff)