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Being grateful for cycleways

cycling if you can

by Glen Smith
The last decade has seen a fierce debate about the role of cycleways in our city’s overall transport infrastructure. Those opposed present them as a luxury for a small number of people at high cost while inconveniencing others. Those supportive point out the potential cycle mode share (over 50% in some overseas cities) and the huge improvements this level of cycling can make in health, our city’s liveability, and climate change.

In this article I will look at the contribution cycleways can make to the overall efficiency of our transport networks, to show that cycleways are one of the most cost effective ways of improving the efficiency of our road network.

In 2012 Opus International Consultants were commissioned, in the TN24 Baseline Forecasting Report, to professionally model the outcome of the National Party’s massive proposed spending on new roads around Wellington as outlined in the Opus TN23 report (see table 2.1, page 3 and 4). Surely, one might think, after spending all these billions the traffic would flow more freely across our region!

It must have been a bit of a surprise when the modelled outcome was not a drop in congestion but an average increase of around 90% and a stunning increase of around 400% from the Hutt (see table 6-4 page 28 of the Opus TN 24 report).

The report projected an increase of around 50,000 car trips (about 20%) with a trivial increase in public transport utilisation. But how, you might ask, can 20% more car trips lead to a 90% rise in average congestion? And how can it possibly cause the massive 400% increase from the Hutt?

The answer lies in the inescapable laws of traffic flow dynamics, and in particular the non linear relationship between road productivity, or flow, (how many vehicles a road can transport) and the density of cars on the carriageway (how many vehicles are trying to use it).

At first as density increases the roads productivity increases linearly. So if 2 cars are on the road and another 2 join then productivity of the road doubles.

flow

This doesn’t continue forever. As more cars are added, a maximum flow is reached at around 1800-2200 cars per hour (‘critical density’). After this point, productivity doesn’t plateau as one might expect. Instead, if more cars are added, flow drops dramatically (the road transports LESS cars) and this continues until finally ‘jam’ density is reached and the road transports no vehicles at all. Trying to add more cars beyond ‘critical density’ is counterproductive – it just makes the road less productive with rapidly escalating congestion. If you want to maximise a road’s productivity you have to limit car numbers to below ‘critical density’.

cars per hour

There are equilibrium mechanisms that work to maintain a road at below ‘critical density’ over time. People try to avoid congestion and so defer, combine or cancel discretionary trips. And for essential trips they use ‘diversion’ to other times (eg people leave for work at 5am) or routes (eg taking the Terrace exit before the Terrace Tunnel). But these can only compensate to a certain degree. Once the overall road use consistently exceeds its ‘critical density’ there is only two ways you can accommodate more transport trips- build another road lane, or encourage the transfer of discretionary trips (trips that don’t require a car) to other modes.

The best option depends on the setting. But in most cases in a city where land has largely been allocated, it is going to be cheaper to transfer trips to other modes. This is because motorcars are a very inefficient mode of transport (see figure below) and the cost of building new road capacity is very high.

corridor capacity

The number of trips that have to be transferred to alternative modes does not need to be that large.

Around ‘critical density,’ a small change in the number of cars using a roadway makes a very large difference in the road’s productivity with a rapid drop in road speed and total flow as car density increases (see empirical data set below). Transferring even 5 or 10% of total trips can tip the road’s productivity back below ‘critical density’ into the ‘freeflow’ section of the graph (moving to the left).

density graph

As the NZ Transport Agency points out in their “Benefits of cycling in NZ communities” booklet:

“Getting just a few people onto bikes can make a difference to traffic flows. On the congested 5km Petone to Ngauranga section of State Highway 2, for example, research suggests that only 10-30 vehicles out of the 250-280 vehicles occupying the space at congested times are causing the congestion.”

As an example that has caused considerable controversy, let’s look at Island Bay. The District Spatial Plan proposes major infill in this suburb. However Island Bay has predominantly one access road (Adelaide Road) and, anecdotally, this route is often congested with traffic backing up approaching Berhampore, John Street and the Basin. It is likely approaching or exceeding ‘critical density’ for increasing periods of the day and there is a high chance that the planned growth will tip this roadway into rapidly increasing congestion.

Building extra road capacity to Island Bay would be extremely difficult and expensive. However a cycleway is eminently achievable. Of these two choices to keep the road access below ‘critical density’ and flowing freely, a cycleway is clearly the most cost effective solution.

The higher the quality of the cycleway that is installed, the greater percentage of discretionary trips it will attract and the greater the resulting efficiency in the parallel road system with growth over time. Building a low quality cycleway is false economy – a high-quality separated dual cycleway will almost certainly pay for itself many times over in congestion savings in the decades and centuries to come. For one option of a high quality cycleway servicing Island Bay see “learning about supercycleways from Birmingham.”

Roads don’t exist in isolation but as part of a road network. The maths involved in the flow dynamics of a road network is complex and depends on a number of factors. However, just like individual roads, road networks also have an overall ‘critical density’ and, again, once average density exceeds this critical level the productivity of the network declines until finally ever increasing areas of the network descend into congestion.

Like a yeast in a sugar solution that multiplies unconstrained until finally it dies in its own poisonous excretions, so unfettered road expansion is ultimately self destructive, inevitably descending into quagmire of its own over-exuberance.

The ‘critical density’ of a road network can be increased by changes in its physical infrastructure, but this becomes increasingly difficult and expensive as the network expands.

In 2019 Loder, Ambuhl et al used billions of vehicle observations from more than 40 cities to look at factors that influence a network’s ‘critical density’. One of the critical results they observed is that

“..we find a sublinear relationship between network size and critical accumulation emphasizing deceasing marginal returns of infrastructure investment.” That is, as a road network grows it costs an ever increasing amount of money to achieve ever decreasing gains in total network capacity.

Peter Nunns noted exactly this effect in new road proposals in Auckland, observing that that “the cheapest major roads we’re going to build over the next decade are as costly as the most expensive roads we’ve previously built.”

cost per km

Escalating sums can be spent on a road network for ever dwindling increases in ‘critical density’ but eventually all possible gains will have been made and the road network will be at its maximal achievable capacity. From this point in a city’s transport infrastructure evolution, ALL increases in total transport network capacity can ONLY be achieved by increases in alternative more efficient modes (cycling, walking, bus, rail) with these modes accounting for an ever-increasing mode share over time.

London is an example of a ‘mature’ city. Table 2.1 from the Travel In London Report 10 shows that total trips between 1996 and 2016 rose by almost 20% from 21.5 to 27.1 million trips. However road trips were static (the road network is ‘full’) with all of the increase in capacity being in alternative modes.

Wellington’s road network is now at the stage where large areas of our network are surpassing their carrying capacity for long periods of the day. At this stage in our transport system’s evolution it is clear that the most critical imperative is to establish the high-quality alternative transport corridors that will attract discretionary trips in the decades and centuries to come and so ensure the efficiency of our road infrastructure and overall transport network on a long term basis.

Why then do so many of our politicians continue to promote road expansion as the solution to our cities congestion problems?

The reason is that road improvements give an immediate ‘hit’ of decreased congestion (which appear good on short term cost benefit analyses). But these gains are rapidly lost over time. Cycleway and PT improvements give relatively small benefits in the short term but these increase over time as the networks expand and mature, with resulting increasing patronage (see Figure 11 – page 23 in this report.

congestion impacts 2

A bit like a heroin addict who craves his next ‘hit’ without thinking about the long term consequences, so our road advocates crave their next ‘roading hit’ without any apparent appreciation or concern about the long-term consequences. And just as drug users have their ‘pushers,’ so road users have their ‘road pushers’, seeking the short term expedient political gains from the road ‘hits’ they promote (“look at these enticing road plan I have for you… only a few hundred million… or a few billion… each. Imagine those wide open stretches of tarmac… go on…. you know you want to..”)

There is a saying in economics that ‘you can’t buck the market’ and the same is true of flow dynamics. Many cities have tried and many have failed.

Roads are an essential part of our transport infrastructure and many trips are impossible without a car. But a city has a limited capacity to accommodate inefficient road transportation. Failing to recognise this can be a costly mistake, as demonstrated by the now over $US300 billion yearly cost of congestion in the USA .

As a city grows, an efficient road network can ONLY exist if it has a network of parallel efficient modes (rail, walking, cycling, bus) that attract discretionary trips and allows the road network to function below its ‘critical density’. The sooner these networks are established the less total cost congestion that will be suffered over time and the greater the total savings.

Cycleways offer one of the cheapest ways of adding this parallel capacity.

Motorists should be thankful that cyclists are prepared surrender the convenience of a car and take to their bikes, often in wind and rain, and by doing so allow them to continue their travels in luxury. They should recognise that surrendering some of the 30% of city space they currently occupy to cyclists and using nearby parking buildings will benefit all. And they should be prepared to offer cyclists the same subsidy (over $120/week for a family of four) that they receive to drive their cars.

But all too commonly they don’t. Self-interest is a powerful force.

The Wellington City Council should hold firm in their resolve and continue to roll out a high quality cycling network across our city. The end result will be a more efficient total transport network and the beneficiaries will be ALL transport users – including motorists.

34 comments:

  1. Zeus, 3. June 2021, 10:17

    How can I get my hands on this $120 per week motorist subsidy?

     
  2. Benny, 3. June 2021, 11:05

    Great article, and I love the conclusion. I draw the line, however, when the family of four leaves their house in the morning in an EV, with four people in it, dropping them off at different locations along the way. Same for carpoolers. Seems to me like a pretty efficient and sustainable way to commute. If car occupancy drops to three in one car, arguably it’s potentially still ok. Down to two or one, then of course, from a city transport dynamic point of view, AT and PT are preferable, as this article demonstrates pretty clearly.

     
  3. PCGM, 3. June 2021, 12:06

    As interesting as Glen Smith’s article is, I’m not sure the data actually supports the conclusion. While the analysis of road capacity and critical density is accurate and compelling, the non-infrastructure mechanisms for reducing traffic flow are even cheaper than cycleways and have every chance of being more effective. For instance, turning parts of SH2 into T2 or T3 lanes involves nothing more than a few cans of paint yet will go a very long way indeed to reducing traffic density below its critical level … whilst costing vastly less in money and carbon than constructing a cycleway alongside the motorway. Similarly, congestion charging can make huge differences to how and when people commute without needing quarter of a billion dollars in new infrastructure. And combining these two things – congestion pricing with different rates for T2 or T3 lane users – is likely to produce vastly larger benefits than our total cycleway investment for a small fraction of the cost.

    As is obvious to all concerned, getting people to change behaviours is easier than getting them to change modes. To put another couple of people in my car and/or to travel to work at a different time doesn’t require me to buy a bike (or an e-bike), improve my fitness level, buy a whole bunch of wet weather clothing, get a helmet and the thousands of LED lights with which cyclists seem festooned these days, or anything similar. And it doesn’t require the council to stump up $228 million plus cost over-runs, either – all I have to do is set the alarm for a different time in the morning.

    So the analysis of congestion causes and the challenges is very good, but the conclusion that cycleways are a panacea constructed of sunshine and unicorns seems shaky.

     
  4. luke, 3. June 2021, 12:40

    Cycleways (or lack thereof) are what’s preventing me from moving back to Wellington. The much improved mobility of being able to feel safe while cycling is life changing. I never want to be car dependant again.

     
  5. bsmith, 3. June 2021, 12:49

    The bottom line is, it’s time to stop the funding of touchy feely projects (cycleways definitely fit in this category), and for the council to focus on supplying basic infrastructure, that ALL ratepayers need/expect.

     
  6. Aidy, 3. June 2021, 13:33

    PCGM. You seem intent on conflating the proposed work by the Transport Agency along SH2 with being all costs for a cycle way, when the high project cost is for seawalls and resilience work that will protect SH2 and the railways from storm damage. You ignore the examples made regarding Island Bay through Berhampore, Newtown and into the city; where would you put T2 or T3 lanes along there?
    I note you say it would be easy to change behaviours and put more people in your car – have you considered getting a lift with others on a daily basis? Is that too inconvenient? Or will you only act when a congestion charge is brought in?
    I’m sorry you have no desire to get fitter and feel that cycling is not for you. But would it be too much to consider that other people do wish to cycle safely, and that can help reduce journey times for all?

     
  7. Fleabane, 3. June 2021, 14:22

    Luke: if that’s the case, we shouldn’t build cycleways and then we wouldn’t need more housing to accommodate people moving here either. Win win.

     
  8. luke, 3. June 2021, 15:15

    Thanks for the encouraging welcome home words Fleabane. Being a NZ citizen I can come and go when I please, bringing and taking my skills with me as I see fit. Perhaps more a win-lose situation.

     
  9. Roy Murphy, 3. June 2021, 15:59

    PCGM – you’ve missed the bit about short term vs long term. Sure you can add paint to the road, but as the saying goes, build it and they will come. Adding capacity attracts traffic, and the same applies to cycling. But with cars it leads to congestion, much less so with bicycles. Adding alternatives, particularly public transport and light rail connecting through to the outer regions, helps everyone in the long term, not to mention the environment. Wellington is a narrow city with only half a dozen through routes. The convenience of free and frequent public transport would soon attract many users.

     
  10. pedge, 3. June 2021, 16:10

    Thanks Glen for a well written and researched article. I’m with Luke when he says improved mobility is life changing. It’s hard to say without sounding condescending, but the people who can’t grasp the facts in this article (which are not new by the way, we’ve known this stuff for decades), maybe need to spend some time living in a real grown-up city overseas before they will understand how good cities work and how much they improve the lives of everyone. As for bsmith, did you read the article? It would be more helpful if you address the facts in the article, or you could you not see them because your head is surrounded by sand?

     
  11. Dave B, 3. June 2021, 19:04

    Thanks Glen for an informative article that helps to sort fact from myth. I like your analogy of the heroin addiction and the focus on the quick-fix to make the addiction feel better, rather than a long-term strategy to break out of it. Car-dependency has become just as damaging an addiction to society as heroin can be to the body.
    Planning for a less car-dependent society has to be the goal, whether it be by more cycleways, better public transport, better urban design that reduces the need for travel, or a mixture of these. People who resist this and continually demand more resources to prop up the costly ‘car-habit’ are perhaps those whose judgement has become clouded by the addiction. We cannot keep on like this, and wise political leaders are those who are prepared to lead us out of the mess.

    PCGM, you are right to point to the need for disincentives such as congestion-charges, to help cull-out vehicle-trips which are unnecessary or can be made by other means, but tend to get made anyway when the real cost is not charged to the trip-maker. A very distortive practice over the decades has been the ‘justification’ of costly road-schemes based purely on measured traffic volumes, with no assessment as to how much of that traffic is frivolous and would soon disappear if faced with a charge. If people were to think twice before hopping in the car for every little thing and instead ask themselves, “Is this trip to the dairy during rush-hour just to buy a newspaper really necessary?”, then transport-system costs for all of us might reduce.
    To those who are opposed to money being spent on cycleways as a means to reduce traffic-volumes, would you prefer a congestion charge on car-use instead?

     
  12. JAB, 3. June 2021, 19:49

    Cycling caters for a pretty limited demographic in hilly Wellington. The quarter of a billion cost should be compared to public transport not the false equivalence of a car journey. Health benefits are a distraction – running for the bus is effective. PCGM is correct we should look at cheaper anti-congestion measures – public spending needs to be effective.

     
  13. Claire, 4. June 2021, 6:53

    Pedge: Many people over 45 have travelled to Copenhagen, Amsterdam and beyond. Different terrain and incentives along with brilliant public transport. Climate Commission is saying they want cycling at 7% of mode. It’s currently 0.9% – always going to be a minority activity. Throwing large sums of money at it is insane.

     
  14. Glen Smith, 4. June 2021, 7:08

    Zeus. You don’t have to apply for the subsidy. You receive it automatically at the expense of others in society and probably have for most of your life. The figure of $120 is based on European research since we don’t seem to bother working out the true cost of cars here in NZ. Dresden University undertook a comprehensive analysis and concluded that “Every citizen of the EU-27 pays for his or her private transport. On average, however, every person living in the EU-27,old or young, male or female, externalizes 750 € per year on to other people, other countries or other generations. Over a period of 10 years, a family of four accumulates a “debt” of 30,000 €. ”
    The analysis uses very conservative methodology for climate change costs (one of the things you pass on to other generations- ie your children/ grandchildren etc)- it only uses ‘avoidance costing’ (what it would cost to avoid CO2 accumulation) rather than ‘damage costing’ (what it will cost once the damage has been done). Damage costing is hard to estimate but likely magnitudes higher (how much will it cost to move Wellington CBD to higher ground?- and the same throughout the world). But don’t worry about that – you won’t be around so let’s just keep driving cars and obstructing people who want to cycle.

     
  15. Peter B, 4. June 2021, 10:24

    Great that the WCC has realised that at $25m per year they can deliver a less congested city for people not motor vehicles. I would rather have 16,000 cycle parks in the city instead of 1,000 car parks and the congestion that every car contributes to. With more healthy people on exercising they make a valued contribution to the climate control and motorists can get around the city easier as a direct result.

     
  16. pedge, 4. June 2021, 10:40

    Claire. You’ve mentioned electric cars before on this site as being a solution, but they will result in the same capacity issues mentioned in the article, so what’s your solution? Please don’t say buses either because the golden mile is at capacity. The facts point to a rail spine from the station to Miramar (my preference is through Newtown, then a tunnel by the Zoo), and of course extensive cycleways. Open up google maps and look at Wellington’s topography. You’ll see that the terrain argument is a fallacy – from Island bay to Kaiwharawhara, Te Aro to Miramar is essentially flat land. Wellington is also a compact city, perfect for cycling. I can’t see how you could travel to places like Amsterdam or Copenhagen and not want that kind of transport freedom for Wellington.

     
  17. Zeus, 4. June 2021, 11:06

    I had assumed it was just made up figures Glen, thanks for verifying. I usually find it’s the other way around – cycles obstructing vehicles.

     
  18. PCGM, 4. June 2021, 11:43

    Aidy – I think you’re missing the essential point, which is that building no infrastructure at all is always going to be cheaper than a cycleway; by any objective measure, a can of paint is vastly less expensive than concrete and tarmac. So if there’s a way of achieving the same congestion reduction ends for less money, why wouldn’t we do that first? I can see an easy $200 million in savings right there. And it’s not like the SH2 cycleway is free. Yes, other work for seawalls and the like is being done at the same time, but it’s not like cyclists are being expected to bump their way along the top of a stony seawall – and the concrete and tarmac needed to turn seawall into cycleway costs actual money and actual carbon to construct.

    As far as my personal preferences go, I walk to work – which has significant climate and fitness benefits, thanks for asking. And while we’re on that subject, it would be kind of nice if the shared paths in this city were treated as shared, because I’m getting a bit concerned by the number of near misses with cyclists who think they’re actually a roadway that can be sped along at 30km/hr+ on their e-bikes.

    Roy Murphy – as Glen Smith points out in his article, we can’t build our way out of congestion and we have a genuine problem that can’t be solved by more roads. There are only two possible solutions; get people to change behaviours, or get people to change modes. This is as true in the long term as it is in the sort term. In addition, traffic growth (technically: vehicle kilometres travelled, or vkt) is not an iron law of nature – it can go down as well as up, and it reacts well to external factors such as fuel prices, the affordability of real estate close to workplaces, incentives and disincentives. So it seems odd to me that cycleway advocates seem captured by the exact same approach as traffic engineers – that we need to predict and provide, and that new infrastructure (in this case cycleways rather than roads) is always necessary.

    Here’s a thought experiment: if you substitute “road” for “cycleway” in most of the comments on wellington.scoop from cycleway advocates, you’ll hear exactly the same arguments being put forward as were advanced by the pro-roading traffic engineers in the 1960s. The type of infrastructure has changed but the old-school thinking doesn’t seem to have budged an inch.

     
  19. Claire, 4. June 2021, 12:34

    Pedge: cyclists can seem be a bit obsessed, dare I say it. It can be like listening to idealistic teenagers. Yes congestion may still be a problem but cycling will not solve that. Charging may make the choice easier to not drive into town.

     
  20. Dave B, 4. June 2021, 13:10

    PCGM, I think the reason that cycleway advocates push for grand schemes on a ‘predict and provide’ basis, is that in our present framework of roads dominated by motor traffic this is seen as the only way forward that will give cyclists a chance. To me, it would be much better to remove or at least calm the traffic on the roads we have, then cyclists would feel a bit more welcome on them. And the way to achieve this is by providing much better public transport instead of continually planning to supersize our road network. This simply increases traffic everywhere, stifles public transport, and worsens things for everyone.

    Zeus, I think you will find that the main instances when cyclists obstruct traffic are when parked vehicles reduce the effective width of the road and cyclists have to pull out around them – allowing extra clearance of course for doors suddenly swinging open. Get rid of on-street parking and cyclists obstructing traffic will greatly reduce. In fact were it not for parking, cycle lanes could be installed much more easily and cheaply on existing roads. Cars are 95% to blame for the plethora of problems we have with our transport system.

     
  21. Aidy, 4. June 2021, 13:46

    PCGM i’m sorry you feel threatened on shared footpaths; maybe that’s how cyclists feel when a vehicle driven inattentively or even maliciously passes too close to them. Unfortunately other than getting out the green paint to make cycle or pedestrian lanes, I’m not sure what can be done if we follow your logic of not building anything new. Of course it would be better if everybody considered the needs of other city users, but that change in behaviour seems beyond us, and the council’s attempts to change things are constantly met with negativity.
    Changing modes isn’t going to just happen without some major improvement in public transport, an oil crisis or a congestion charge, none of which look likely right now so what gives ? We carry on wasting time writing crap on’t int’net i guess.

     
  22. GK, 4. June 2021, 14:27

    PCGM: “… the concrete and tarmac needed to turn seawall into cycleway costs actual money and actual carbon to construct.” You do realize that what’s being built on top of the seawall is a 5m wide road designed for heavy vehicles (and that includes the new “shared path” overbridge north of Ngauranga). All done for resilience (emergency/disaster access) and all from the cycling budget. Then there’s the fact that the project is loaded with ecological restoration, again all from the cycling budget.
    A big WK-NZTA raid on the cycling budget for what is mostly a road and rail seawall project with an emergency/maintenance access road thrown in.

     
  23. PCGM, 4. June 2021, 14:57

    Dave B – I agree the best way of providing more space for cyclists (and pedestrians, for that matter) is to reduce traffic volumes so there’s a safer, less congested and less contested environment for everyone. Incentives like cheaper public transport fares and disincentives like congestion charges would seem to be the best way to achieve this, and in some cases (such as fare decreases) the changes could be made in a small fraction of the time it takes to design, consult on, consent and build new cycleway infrastructure.

    Aidy – Perhaps the rationale of “motorists are horrible to us so we reserve the right to be horrible to you” is not the best way to gain pedestrian support for cycling infrastructure – it rather smacks of entitlement. And your generalised negativity about other forms of change simply doesn’t stack up; for instance, peak ICE car production appears to have been in 2017 and sales have dropped from there; the International Energy Agency is saying oil production is falling and petrol prices are rising and it’s a long-term trend; mode change is gradually occurring in the capital. I know there’s a temptation to cry TINA (There Is No Alternative) from the rooftops about cycleways, but here’s the thing – there’s always an alternative, and some of them are quite good ideas.

     
  24. Quash2772, 4. June 2021, 15:04

    All looks good on paper but there are too many barriers in practise for cycling to take off. Wet and windy days, and how this works for a family unit with school drop offs and work. Destination to work or school too far away. It will only be a practical option for a minority of people, meaning cycleways will never be the most practical option and funding should be weighted correspondingly. However the biggest failing of councils is doing the cheap and less practical approach because it makes it look like they are doing something. The current council plan appears to support critical density on all roads.

     
  25. luke, 4. June 2021, 16:04

    Quash, Copenhagen has high cycle mode share and the climate there isnt Hawaii. It makes Wellington look positively tropical.

     
  26. Andy Mellon, 4. June 2021, 16:14

    Wind issues, except on the very worst days, are irrelevant with eBikes as well. I do school drop offs. We all walk (about 2km) and then I walk to work after that (about 3.5km) – rain and wind be damned. The walk is valuable for our mental and physical health! (Though there are complaints from the littl’uns on the worst days, we usually get over that by wearing our wellies, jumping in puddles and unblocking leaf-filled stormwater drains – their choice, not mine!)

     
  27. Wellington Commuter, 4. June 2021, 16:24

    Luke, sure Wellington has a climate more like Copenhagen than Hawaii but our terrain is more like Hawaii than Copenhagen …

     
  28. Dave B, 4. June 2021, 16:59

    Wellington Commuter, terrain does not stop e-bikes. I know, because they regularly cruise past me while I am puffing and sweating up Wellington’s hills on my non-e-bike.

     
  29. Conor, 4. June 2021, 19:32

    PCGM – the council is not allowed to introduce a congestion charge.

     
  30. Albert Ross, 5. June 2021, 7:05

    This article is more convincing in its argument that “more roads” is not a good solution to congestion, than it is in its argument that “more cycleways” is a good solution. There are better alternatives.

     
  31. Geoff Cameron, 5. June 2021, 17:48

    With added cycleways, what is the projected increase in car trips and congestion? I’m sure the cycleways will have no impact.

     
  32. Dave B, 5. June 2021, 23:02

    Geoff Cameron, instead of being so negative at attempts by others to make the city a less traffic-dominated place, you could help by reducing your own car-usage and cycling yourself. That way you could contribute to the solution, not the problem.

     
  33. Glen Smith, 5. June 2021, 23:06

    PCGM. You list 3 options as solutions for the projected decline of our city into a congested quagmire. All of these have been tried overseas and none of these are likely to work by themselves in the long term.

    One is T2 or T3 lanes which improve the carrying capacity of a single road corridor of our road network. The second is raising a barrier to car use by congestion charging. And the third is diversion to alternative travel times. Increasing the carrying capacity of an individual road in a network usually increases total car trips more than the increased network ‘critical density’ achieved. This is because it shifts the network’s equilibrium more towards overall car dependence. This is essentially the same effect as National’s road plans (which also improve capacity of individual roads but, as the modelling in my article demonstrates, increases total network congestion).

    Road pricing can reduce low value car trips (the ‘frivolous’ trips Dave mentions) but not essential or high value trips unless people have a viable alternative. The majority of car trips from the Hutt, who want to travel across the CBD to areas to the south, have no viable cycling, walking or PT options so any congestion pricing would be largely punitive. A seamless across town rail corridor would be the best solution. I mention diversion to alternative times in my article and, as I said, this can compensate to a certain degree but is doomed to failure with ongoing growth (do you think drivers in the congested cities overseas haven’t tried this?)

    The only way in the long term to prevent escalating road congestion is to install parallel corridors of alternative modes that are of high enough quality to attract discretionary trips. Cycling is one of these, the others being walking and PT (most commonly bus and rail). I’m not sure where I said cycleways were a ‘panacea constructed of sunshine and unicorns’ – you must have been reading a different article. What I said is that cycleways are commonly the cheapest way of adding this parallel capacity- the others being walking and high quality PT which, as you likely know, I also support.

    Your reluctance to buy an e-bike is a fool’s economy. I paid $2000 for my e-bike about 10 years ago. I travel at around 40km/ hr (usually overtaking gridlocked cars) and trips cost around 15c in electricity with no petrol/ parking or gym fees for exercise. The bike has paid for itself many times over. Electric bike sales will soon surpass new car sales. Wouldn’t it be nice if those people could use their share of the subsidy pie to build safe places to ride them (or do you want all the subsidy money for yourself).

     
  34. Glen Smith, 5. June 2021, 23:35

    Pedge. As you say the facts in this article have been known for decades but we seem to be slow learners. It is funny that we are world leading in things such as digital technology, boat design, geothermal power, agriculture etc but when it comes to city transport design we are like the child reaching for the red hot stove after being told it will burn us and with a brother with a bandaged hand in the background. It seems we won’t learn until we are suffer first.