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Slow Down (again)

This is a guest post from NCD

Some months ago we looked at the cost of Road Traffic Accidents (RTAs) in New Zealand.

What if I was to suggest that there is a single change that could be made to Auckland’s transport system that is cheap to implement and that will have dramatic effects of road safety, quality of place and promotion of active modes of transport? Cue incredulity.

First, let’s set the scene. If safety is one of the criteria by which the effectiveness of road engineering is measured, then it would have to be the single biggest failure of a professional discipline in human history. This is after 100 years of effort to improve the situation. How much longer do they need?

When the Airline or Rail transport industries run conferences on “Safety lessons we can learn from road engineering” I hear they aren’t well attended. Ah, that feels better.

And all the while the solution was staring them in the face: Reduce Auckland speed limits to 30 km/hr.

If you turn down the stereo you’ll be able to hear the AA’s howls of protest from your place.

Kent did a post “Slow Down” which made some of the points below. But that was like, you know, way back in 2012, and not much has happened in Auckland since then, so here we go again. That post has a graph showing that the risk to cyclists of a fatal accident reduces dramatically as speed reduces.

Here’s a similar one from SFstreetsblog (a prettified version of )

NCD - Pedestrian Injurys at impact speeds

Occasional contributor Glen K will dispute the figures, but even the most conservative figures I’ve seen show you’re four times more likely to die at 50km/hr compared to 30km/hr.

A few months ago Bryce P. did a post on the Cycle Action Auckland site that linked to a study in the British Medical Journal, and it’s that study that I’d like consider in a bit more detail. It shows a 42% injury reduction in areas of London where speeds were dropped to 20 miles/hour. It’s hard to convey how significant this is. If this was the 1990s we’d have a GIF with stars exploding, a scrolling ticker, and that number jumping out of the page to meet you. In the world of public health interventions a 5% reduction in morbidity or mortality has researchers high-fiving each other (OK, academics don’t high-five, but you get the idea).

From the report: “Casualties as a whole were reduced by 41.9% (95% confidence interval 36.0% to 47.8%), with slightly larger point estimates for the reductions in all casualties in children aged 0-15 and in the numbers killed or seriously injured. The numbers of killed or seriously injured children were reduced by half (50.2%, 37.2% to 63.2%). The point estimate of the reduction in number of people killed was slightly smaller at 35.1%, −1.9% to 72.0%).”

The study is robust (see the confidence intervals above. The sample size was almost a million accidents!), and checked for things like migration to neighbouring roads. Here’s a map showing how much of London is covered:

NCD london_30km_zones

The authors of the study in a subsequent interview have estimated the 30km/hr zones are saving 200 lives a year in London, and this would increase to 700 if the zones were implemented city-wide. The onus is on those who want to leave them at 50km/hr to demonstrate that the productivity gains justify the 72% increase in injury and 100% increase in child serious injury and death that the higher limits cause (because that’s what proponents the status quo are arguing).

Why is this strategy so successful? Because at its heart it takes the HPtFTU seriously. The what? The human propensity to fuck things up. (Complaints about the language to Francis Spuford.

The airline industry has also been taking the HPtFTU seriously for quite some time now, with spectacular results. That’s why planes have co-pilots, why airline mechanics account for the tools they might have left lying inside the engine, and why airlines run a “no fault” reporting system.

Here’s a chart from the NZTA’s 2011 accident report. It’s titled “Factors contributing to crashes” It could have been titled “The HPTfTU while driving”


The problem though is that “Too fast for the conditions” in 29% of crashes might lead one to think there’s 71% of accidents where speed wasn’t a factor. Actually, there’s 100% of accidents where speed was a factor. (I don’t believe any stationary cars are represented in the stats). You could argue that “too fast for the conditions” should be at 100% – if not too fast for the condition of the road, then too fast for the condition of the driver’s mind!

And this is why taking the HPtFTU seriously and reducing speed limits is so effective- it affects every type of crash. Texting, changing the radio channel, thinking about something else, pretending not to look at the hottie in the car next to you, assuming there won’t be anyone coming, sun in your eyes, headache, recent argument, arrogance, ignorance, incompetence, unbalanced. We aren’t about to stop being human, and we need speed limits that reflect that.

All this saving lives is sure to have some side effects. Yessir. Our city becomes a much nicer place to be. Auckland goes up a few notches on the awesomeness scale. Other modes of getting around become more attractive, safer, with all the health benefits that Mr Money Moustache has so eloquently described. There’s real potential for a virtuous cycle of improving conditions causing more people to change modes, which further improves conditions which causes….

So what’s stopping us just doing it? There are three main objections to lowering urban speed limits: “we’re different”, productivity losses and the difficulty of enforcing limits.

The “we’re different” argument could also be called the “we need to study that” argument. This is a typical official response from NZTA/MOT/AT. The coroner just released a report on cycle accidents in NZ. Sample size: 13. Glen K. very kindly pointed out that 13 isn’t a very big number, and he has data on 84 fatalities. Good point. And that’s why the London study mentioned above is so important. A million accidents gives real statistical grunt. Londoners are human too, they live in streets, drive similar cars. What isn’t needed is another study. What’s needed is leadership. Action.

On to productivity losses. We’re in a city where the CCFAS is projecting average speeds of 11km/hr in a few years, so that pretty much closes the case for the city centre. Second, I’m not suggesting we change motorway speeds. Allowing 100km/hr on motorways would reduce the productivity losses for most longer trips around the city, especially once the WRR is completed. So balding, grumpy traffic engineer, I offer you an olive branch: you’ve done a great job of making motorways safe. Thank you. (But no, the answer to every traffic safety problem is not “make the road into a motorway”)

As for suburban travel, arguing for productivity losses being the reason not to change implies 50km/hr is some sort of sweet spot where we’ve got the balance between safety and productivity right. Not so, says 100 years of stats. With a 30km/hr limit you could expect a 5km suburban trip to take about 10% longer suggests some research. That’s a difference measured in seconds, not minutes.

Arterial roads are a bit trickier- you’ve got the trade-of between them being routes that are useful for active modes, and the fact that they move a lot of cars. Places like Dominion Road. Here’s a proposal: reduce speeds on arterials to 30km/hr until separated infrastructure is built for vulnerable road users. Let’s see how fast AT can build bike lanes then!

The argument around difficulty in enforcing limits seems to be enshrined in NZTA’s big fat book of road engineering wisdom- you can’t reduce a speed limit much below the speed the traffic is observed to travel at. Enshrined defeatism. I don’t believe this approach is taken with open road limits, and it shouldn’t be a factor in urban speed limits either. The whole self-explaining streets idea is great, but realistically, they aren’t going to be everywhere in Auckland any time soon.

Why don’t we try lower speed limits and see how it goes? I suspect it is not a problem that liberal speed camera deployment wouldn’t fix, and wide scale changes would create a mini firestorm of indignation, so AT gets a free publicity campaign.

And what’s the worst case scenario? We have to add the traffic calming in later. That’s not the end of the world.

In London the zones have mostly been done with traffic calming while Portsmouth in the UK and Graz in Austria have changed most of their streets to 30km/hr without traffic calming, and Cambridge (UK) is currently proposing to change all but arterials with a budget of only £500,000.

And the secret formula for change? Stroppy women plus visionary leadership. I’m confident that NZ has the former, if not the latter.

One of the key factors that is identified in bringing a change in the Netherlands from a car oriented society to a more balanced one was that women (in the 1970′s) got angry enough about road fatalities that they got stroppy and organised. Brett Toderian made the same point about Vancouver not allowing motorways in the city centre: it was protesting women that were a significant factor. We need some Kiwi women to continue the tradition. An aside to AT: how’s your board and executive management gender balance?

Lastly, a personal plea to Lester Levy. You’ve had a large and significant role in leading Auckland’s health institutions- thank you! This is really a public health issue that spans health, transport, community and environment. There is no other measure that can be implemented with such huge gains for so little cost. You and your board have an opportunity to show real leadership. Ask AT’s management to report at your next meeting with either a plan to implement widespread 30km/hr zones or a convincing argument why the status quo of a steady stream of death and injury is the best they can do. Failure to do anything on your watch is making a decision that in effect says “I’m going to sacrifice some Auckland lives for an unproven efficiency gain.”

117 comments to Slow Down (again)

  • Bryce P

    Fantastic post NCD. Bring it on #aucklandtransport. What is the worst that could happen? We save some lives and make the streets nicer for ALL users.

  • iiq374

    Number one thing preventing this – trains and buses that don’t turn up. People will defend to the death all parts of the car journey until there is a competent PT system

    • Bryce P

      It’s got virtually nothing to do with speed limits. We’re not discussing removing motor vehicles, just slowing them down.

      • iiq374

        Which without a decent alternative amounts to the same in most people’s perceptions (or emotive response anyway)

        • How much of the average car journey is spent on residential streets? 5/10%? Most of it is spent on arterial roads which are unlikely to be affected.

          That means the difference in travel time will be minutes over 1-2 kms, if that. And that is assuming that your travel is completely unhindered by other traffic and you were able to travel at 50km/h the whole way on those residential streets. How many children’s lives is that worth?

          Buses on average wouldnt do much more than 30km/h so it wont hardly affect them at all.

          • Frank E

            I think you didn’t read the post. NCD thinks arterial roads should have 30km/h limits.

            For buses, the average speed will be 30km/h but obviously between bus stops they’ll travel faster than that so the average speed will certainly decreases.

          • Yes I read the post very carefully and in fact have just written one myself on the same topic on the CAA blog. What NCD suggested is to lower the limits on arterial roads until active modes are separated, not to exclude arterials all together. That would certainly speed up AT’s implementation of separation.

          • Frank E

            But some streets like Dominion Rd as an example can’t easily have seperated cycle lanes built. As I said below AT says it would cost $50 million. A one size fits all policy isn’t the answer.

            I assume active modes being seperated = cycle lanes, as all other modes are seperated already.

          • Max

            “But some streets like Dominion Rd as an example can’t easily have seperated cycle lanes built.”

            That is patently untrue – it can be done easily. It only costs 50 million because we prioritise cycling AFTER cars and buses, and then there’s no space left over, or getting the extra space costs oodles because of kerb changes and land acquisition. You are simply putting all the cost of not sharing the road space on cyclists, as if the cost for motorists was zero. This is nicely aided by the fact that cycle lanes tend to be on the outside of the corridor, so people get all riled up by “the cyclists are taking my front yard land”.

            I can already see you take the secondary tack “but should we really prioritise cyclists over buses on a road like Dom Road”? Probably not, but go to the next street over to the west (Sandringham Road), and the next street over to the east (Mt Eden Road). All major bus routes too. So cyclists get moved on like an unwanted stepchild again – until our politicians finally get some spine. If PT is too important to reduce its convenience for cyclist’s benefit – well then reduce the convenience for car drivers!

  • Jon_K

    Do you have statistics to hand for how many lives would be saved in reality? What you’re suggesting would result in all modes of motorised road transport (includes buses) being impacted – Which as you’ve mentioned many times has a massive financial impact due to “lost productivity”. FWIW, “lost” productivity is a tricky beast because it assumes that people won’t work extra time to try and “make up” for being late. My experience is that people work longer hours when there is congestion at the end of the day, though by no means am I suggesting that this is the norm.

    There’s no arguing the science behind your concept, it is simple physics after all! The question that needs to be asked is “how much of an issue is this?”. I’ve had pedestrians run out in front of my vehicle on numerous occasions, at all times of day (I work shifts so sometimes need to drive) – More often than not, the pedestrians do this when I’m driving slowly. There is no economical way to re-educate some people (wish I could have put that better).

    • Bryce P

      Relax. Here is how it could work:

      Have a read and then come back with arguments.

      • Frank E

        Are you suggesting arterial roads like Dominion Rd be reduced to 30km/h? On Dominion road you can’t build dedicated bike lanes (AT says $50mil) so its not cheap. Also bus and car travel times will decrease quite a bit which does effect productivity.

        I’d support quiet suburban streets have their streets dropped to 30km/h but we do need higher capacity roads that carry car and bus traffic reasonably quickly like Dominion Rd.

        • Bryce P

          It would be interesting to see actual travel speeds (not max but average over distance) down Dominion Rd. I bet it’s close to 30 kmh during daylight. I also do not look at Do.inion Rd as an arterial, more a very busy distributor road.

          • Frank E

            At peak hours the car lanes certainly don’t but the buses certainly can reach 50km/h on the bus lanes.

            I would classify it as an arterial, it carries a lot of traffic, its pretty well designed for it and its the only significant road for a sizable chunk of the isthmus (going downtown).

            Regardless the current Dominion Rd project has a lot of (good) pedestrian improvements. A few more pedestrian controlled traffic lights and pedestrian islands.

          • Bryce P

            You’re referring to max speeds, not averages. There is a big difference.

    • Jon what are your figures for the amount of driving that is actually cutting into productive work? In other words is there much low value driving, especially on suburban and urban streets? Yes there is is. Taking the SUV to pick up lattes, the school run, whatever. Basically time spent driving on these roads is not so valuable, and in fact the value of ‘time savings’ overall is highly contentious and open to a great deal of questioning.

      But also aren’t you just a little more productive when you’re still alive, or not in hospital?

      • Frank E

        The same can be said for time savings for Public Transport can’t it..

        • Patrick M

          ah but on pt you have an option – legally – of doing some productive work, be it on the phone, tablet, laptop or even a notepad. Or just chilling and letting the UN healthy stress drift away. Try this in a car and you could receive a fine, maybe kill someone but atheist suffer the raith of your fellow citizen’s.

    • NCD

      John, you ask:
      i. Statistics: The London study is fairly conclusive. It is impossible to do such a robust study in NZ as we don’t have enough people (see probs mentioned with coroner’s sample size)
      ii. Productivity losses:
      a. As Patrick says, a lot of trips are about nothing much in particular.
      b. Read the Mr Money Moustache article- if people were really worried about lifetime productivity they’d ride a bike ;-)
      c. Communications tech just made PT more productive than driving. Hasn’t caused wholesale abandonment of cars, although the younger generation gets it.
      d. I think there is a good case for prioritising freight movements- by getting cars out of the way of freight, not by building more roads.
      e. I was playing with a Android speedo app yesterday and Mission Bay to Newton averaged 25 km/hr in the evening although close relative in the driver’s seat was driving “with the flow” (to put it charitably). The point being that average speeds are already low. People are happy to do zero (at a traffic light) but doing 30 is seen as some sort of torture. We need a national chill pill.
      iii “How much of an issue is it?” – ask someone whose partner/parent/child was killed in an RTA. Or ask the person themselves if they were “only” permanently disabled. I would wager that every adult in NZ knows one such person. It’s not about re-education of those pesky pedestrians- the point was that we need speeds that take our humanness seriously.

  • Irrefutable logic. Nice work NCD. People, it seems, are happy with the death and injury levels, cos you know, cars!

    If the airline industry killed this many of its users each year every plane would be grounded.

    • Bryce P

      Here is an excerpt from an article I’ve linked to lower down the thread.

      “The Sustainable Safety vision specifies that
      safety should be a design requirement in road traffic
      in the same way as in the design of (nuclear) energy
      plants, refineries, or waste incinerators, and also air
      and rail transport.
      If we want to integrate safety as a design requirement
      in road traffic, we have first to recognize that
      society appears to be prepared to accept many road
      crash casualties. Paradoxically, in a country like the
      Netherlands, we would never accept three widebodied
      aircraft crashes in a year. Even a single plane
      crash evokes a dramatic societal response.”

    • Don C

      And yet you are against cycle helmets…what a fool :(

      • Bryce P

        Wrong. I think cycle helmets have their place. Allow me, as a responsible adult, to determine where and when I choose to do so. If I go mtb’ing I always wear a helmet. If I were into road cycling (as in fast riding) I would also wear a helmet. Likewise if I were looking at riding along fast or very busy corridors on the road. To ride to my local shops, at 20kmh, along residential streets, of which a few have traffic calming, does not require a helmet as the level of risk is reduced by a huge margin. I’m comfortable with that scenario. You’d be surprised what I do for a job :-)

        • patrick M

          Actually I’m going to disagree. Your argument could also be used for not wearing seat belts whilst driving.

          It’s not so much the speed you may be travelling at but the actual height, and angle, one falls from when impacting very unforgiving concrete or tar seal. A slower forward velocity may mean less kinetic energy perpendicular to the path of impact, but this energy is still there and damage to ones brain still occurs from blunt trauma. After all your brain is largely soft tissue floating inside your skull, and concussion can still be dangerous. Try tripping yourself up on the street and landing on your head. See chapter 13 –

          If you choose not to wear a safety belt or cycle helmet as mandated by society (law) then fine. Any and all expenses incurred in the recovery and repair of any damages caused can be covered solely by said individual rather than society.

          Its like the old adage of socializing the cost, but capitalizing the profit.

          • patrick M

            Another easy experiment – walking normally along a street and just walk into a power pole face first – bet it hurts like a ..,

            Then try it with a face guard – like softball catchers. Wont hurt as much and a lot less damage.

            And this is just from walking.

          • Bryce P

            If cars were restricted to 20kmh we wouldn’t need a seatbelt law, much less airbags. See the relevance?

          • patrick M

            walking into said power pole is probably going to be <5 kmh, so the only safety advantage of the car is the distance being use to bleed off speed as the passenger still gets flung into the dash.

            The passenger while traveling in the car will contain potential energy that still converts to potential with the sudden 20 kmh ceasing of momentum.

      • SteveC

        drivers and passengers wearing helmets in cars would probably prevent/mitigate more head injuries per year than for cyclists in a decade, yet we don’t see that one advocated much

  • Bryce P

    And for some more actual evidence on how speeds can be reduced – Copenhagen. And the benefits that ensue:

  • Max

    One of the best posts here in recent months. Great stuff! Lets start with some suburbs where we do blanket speed reductions. And change stupid situations like where Ponsonby Road is 40 km/h, but the surroundings streets are 50 km/h.

    And get rid of the ridiculous “40 km/h speed limit around the immediate vicinity of this school on school days between 7:55 and 8:25 am” speed limits. If ever anything made me embarassed to be a traffic engineer in New Zealand, it is those signs.

    • Max, those signs might make me the angriest of just about anything that’s lame about car-dominant traffic engineering. “Get those kids off the streets by 3:15 or else god help me I’ll run them over…” — what arrogance.

  • SF Lauren

    I ran some numbers on this for one busy section of road here in auckland. It worked out that by reducing the speed limit from 100 to 80 would cost so much in terms of increased travel time that you would need one less person to die on the road each month to offset the cost. Given this section of road only had one single death in the past 5 years that would have been imposdible.

    Hardly a conclusive argument to having high speed limits but it does sort of show that low speed limits on the wrong roads can really stuff up a transport network.

  • John Polkinghorne

    Nicely argued NCD. To add to the debate a bit, Ministry of Transport stats suggest that the current average car speed in Auckland is around 30 km/hr ( That is, averaged across all travel, on motorways, local roads, in peak times or out of it, we’re already at 30 km/hr on average. That’s a bit lower than the NZ average, incidentally, which is more like 36 km/hr.
    Reducing speed limits on some local roads – especially those without proper separation for cyclists and pedestrians – won’t affect people’s travel times all that much. Especially when considering all the time we spend doing less than 30 km/hr anyway – when stuck in traffic, or waiting for a light to change, and so on. However, there could be real safety benefits, and other travel modes (cycling in particular) would start to look a lot more attractive.

  • Awesome post. I have just done one on the CAA blog on the same topic and how New York is looking to copy London ( but you have nailed it.

    Love the reference to Mr Money Moustache. I found him a few months ago and he is great – especially his artciles about “Car Clowns”. Plenty of those in Auckland.

    I was at the Devonport-Takapuna meeting on Tuesday and they were discussing that the Police (????) opposed a 30km/h limit on Victoria Street in Devonport. I just cant understand that – what possible reason could the Police have to oppose that? Perhaps they dont want a law that is hard to enforce but they seem to have no problem supporting plenty of other laws that are almost impossible to enforce.

    How many children’s lives is delaying implementing this speed limit worth NZ Police/NZTA/AT/MoT? Please let us know so we can be prepared to mourn them.

    • Bryce P

      The police opposed 30 kmh speed limits? What the! That’s worth writing to the minister.

      • Bryce P

        Is their opposition in writing? Meeting minutes?

        • Good question and one the Local Board were going to look into.

          Joseph Bergen in particular was very supportive of the idea of a 30km/h limit as was all the board members present. Jan O’Connor was particularly positive and I was really impressed with her attitude in general towards walking and cycling. Mike Cohen and Allison Roe are already big supporters of cycling and walking. Overall a positive nd forward thinking board for the area.

  • Bryce P

    And here is another, recent, study (thanks Max).

    While the risk of fatality at 60 km/h is reduced compared to earlier studies, the difference in risk between 30 km/h and 60 km/h is huge. Under 2% risk of fatality at 30 km/h rising to 20% at 60 km/h.

  • JBarnes

    Great stuff. My only concern is that without traffic calming we are relying solely on drivers (1) seeing the 30km/h signs, and (2) obeying the 30km/h signs, especially when the streets are wide with good sight lines. Kind of goes against your HPtFTU principle?

    It will be interesting to see how successful Cambridge is in introducing a 20mph limit without traffic calming.

    • Max

      The thing is – even if 50% of the drivers obey it and drive 30-35, and the rest keep driving 45-55, we already have a massive safety bonus. Plus its a start to changing the whole culture, and you can always add targeted traffic calming later.

      The only real argument against a 30 km/h speed limit w/o specific traffic calming is the “but if it isn’t working in practice, then you are weakening all speed limits” (i.e. the “who ever slows down at roadworks” argument).

      And to that I say: This is not a problem of our speed limits, it is because we rarely ever enforce them. Get busy enforcing our rules already! We are far too molly-coddling to drivers breaking the rules, because our politicians and our police are all afraid of being accused of revenue gathering. This is an entrenched cultural attitude WE HAVE TO BREAK.

      We should be responding to those whingers in only one way: “You are threatening my life if you speed. You are threatening the life of my nieces if you speed. You deserve any fine you got, and it’s probably still too low”.

    • NCD

      Good point.
      I’m all for traffic calming.
      Main problem is that current response to HPtFTU is to do nothing, or to look for an engineering solution. I suspect part of the interview process for management jobs at AT is ability to be a hand-wringer. Imagine ATman wringing hands, saying “We’d love to reduce speeds, but we have to do traffic calming, and we’ll only have the budget for that in 2036″
      ATactionman (or more likely ATactionwoman) is a species that needs to have a quick evolutionary process, but we need to break the mould (to badly mix metaphors).

      Humour break: This cartoon has the best ever take on congestion, social class, traffic speeds and bicycles.

      • David B.

        NCD – great post and a wonderful idea for Auckland, so why not pilot it for a year on all non-arterial roads and see how many lives we can save? The health benefits will only get higher and higher as our population density increases. It’s a cheap solution to a serious problem, which pretty much makes it a no-brainer doesn’t it?

        • Exactly – what is the worst that can happen. We need to stop studying everything to death and just do trials. The parklet that is now on Albert Street is a great example. Let’s start some road diets using bollards and planters and see what happens, New York style.

          If the world comes to an end we can easily go back to our auto dependent ways – but that hasnt happened anywhere else and there is nothing special about NZ or Auckland.

  • Bryan

    In the majority of cases they’re a waste of time – during the posted times there’s usually too much congestion for anyone to travel as fast as 40km/h, and at other times there’s no need for a reduced speed limit. Admittedly, that’s based purely on 10 years personal experience around Waitakere School, Swanson primary, and Waitakere College.

  • kbilly

    At the same time we should reduce train speeds to 30km/hr too.

    • Counterpoint

      Not that I’m intrigued, but why might we do this…?

    • A little perspective:

      Cars killed or seriously injured 1,751 pedestrians or cyclists last year, plus a further 10,823 injuries to motorists.
      Trains killed or seriously injured 6 pedestrians or cyclists last year, with zero injuries to train users.

      Lets worry about the twelve thousand people a year being hospitalised by cars, before making knee jerk reactions about six hurt by trains.

      • kbilly

        What’s that as a percentage of car trips and train trips?

        • Bryce P

          Work it out and let us know :-)

        • Who cares? It doesn’t matter what the rate is with only six incidents a year. Slowing the trains down can’t achieve much if the don’t cause a problem to begin with.

          You’re just being a grizzly troll demanding trains be slowed down too, simply because slowing cars would be so effective a reducing injury.

      • SF Lauren

        Nick you numbers are way out. On average 36 pedestrains are killed on New Zealand roads, not 1,751. Of the number that are killed by vehicles going more than 30km/h I dont know what the number is however about 5 a year die in their own driveway.

        Of the very very very few pedestrains that are exposed to a train at a level crossing about 2 die each year.

        • wtl

          LOL. He said “Killed or seriously injured”. Can’t you read?

          • Apparently he can’t.

            Focussing on just deaths isn’t particularly helpful, because death is relatively uncommon and therefore arguably less of a problem. Serious injuries are much more common, and furthermore they have huge economic impacts typically requiring hundreds of thousands of dollars of immediate medical treatment and rehabilitation, and often leaving the victims permanently disabled and unable to work or otherwise contribute to society much, if at all. A death is a horrible thing, but a thousand broken legs and shattered pelvises are a bigger problem for the country.

            And yes, on the second point you are absolutely correct. Because so few pedestrians are exposed to trains at level crossings, relatively speaking, there is very little to be gained by slowing trains down.

      • SF Lauren

        If you crnuch the numbers in order for roads to perform to the same level of safety as a level crossing based on risk exposure you would expect about 2000 deaths a year rather than the current 36.

          • SF Lauren

            Rather obvious i thought, roads are significantly safer for pedestrians than level crossings.

            Therefore if you want to address what is a real hazard you would remove all level crossings.

            In regards to a 30km/h speed limit on local roads, this would be ideal on some roads and a complete waist of time on others. Driving down the Great South Road at 30km/h would be unbearable.

    • Max

      What nonsense – clearly a troll. Trains don’t travel in the same corridor as other users. They only cross at a very small number of highly controlled locations. Trains also do not overtake (again except in very controlled circumstances). The comparison isn’t even apples and oranges, it’s more like apples and coca cola.

    • V Lee

      Slowing down trains will make no difference to safety – you will be just as dead if you are hit by a train going at 30km/h as by one travelling much faster. Neither will it allow the trains to stop in time to avoid hitting you. It is completely different with cars. It has been demonstrated time and time again that a car travelling at 50km/h is much more lethal or damaging than one travelling at 30km/h.

  • Jacques

    Love this post. But maybe there needs to be some account taken of the benefit (however small) of reduced commuting time by driving faster. This should be balanced against the negative impact of the increased safety risk to find an optimum, maybe by using an accounting mechanism similar to that used by insurance companies to factor in human cost. It wouldn’t change anything to the outcome, but it’d appease people’s worries that the decisions are the result of a balancing act, not just taking safety into consideration (in which case, the ideal situation would be not to commute of course, which is impractical).

    • Jacques

      A side benefit of the measure is that it’d make cycling and PT much more attractive to a lot of people by totally cancelling the speed advantage they might otherwise get from using their car (if they were driving outside peak hours that is).

    • Max

      So you are asking essentially, for “more balance”, so the economic disadavantages of speed limits don’t impede us all. Sorry, I would respect that view a bit more if most things in our transport system weren’t all geared around economic impacts (including even the safety calculations!).

      The balance you seek has long ago been lost – in favour of a very capitalist/mechanistic system, in which it is ACCEPTABLE that, calculated on average, X persons are okay to die so some thousands of persons get to where they want to go slightly faster (as shown by the original post showing HUNDREDS of lives saved in London every year).

      That doesn’t mean that we should all mandate driving at 5km/h top speed, just so we can reduce the crash fatality rate by 99.9%. But I don’t see why you are calling for balance, when the scales are weighted so badly. We can pile a lot on one side of the scale before we need to check again whether the balance is right.

      • Max

        Oh, and pleas don’t take my post as a personal attack, Jacques – I see you support the slow-down idea in general. I am just surprised how ready we all (including me!) often are to temper our convictions by think we need to “balance” in favour of the already dominant mode. We are so caught up in that paradigma…

      • Jacques

        I think this might be the engineer in me who likes to find an optimum that they can justify. Personally I think it’s a good idea regardless of the way it’s presented and it seems (intuitively) like 30kph would strike the correct balance between safety and efficiency. My point was just that this should be a bit more explicit because there would be a lot of push back and the effect on commute time needs to be quantified to address criticism from people who are not in favour.

    • This seems to be a common “economic productivity” argument – “but we have to go slower so it must cost us!”. There’s two ways to tackle this:

      Firstly, the actual travel time lost is invariably minimal; most of the delay encountered on journeys is due to other traffic and delays at intersections. Having to travel slower on the links is a small proportion of the overall delay (esp. if most arterial roads are unchanged).

      However that speed reduction makes a big difference to the environment for others. As mentioned, there are massive safety benefits for ALL road users (esp. peds/bikes); these alone invariably outweigh the travel time losses. A lower speed environment also encourages more active transport, thus generating considerable health benefits for the community (and less money sent overseas to the oil companies). And typically slower street environments (coupled with the increase in active road users) improve patronage of local businesses and raise residential property values. All of these economic benefits will comfortably trump losing a few seconds of travel time.

      • Jacques

        This is exactly what I was proposing to do: letting people know about the likely consequences of the change. It’s quite likely that the extra time on the road would indeed be minimal (especially for peak traffic commuting times) and that the safety gain would be large. Showing this should make it easy to accept.

  • SteveC

    while I agree with the concept of lower limits (and in the end, that’s largely about managing the expectations around the ability to travel at 50 kph on suburban streets) my preference would be to use a lower design speed for streets so they become self-enforcing, less width, more side friction, curves rather than straights to bring the driver’s visual focus closer to where they actually are

    I know that there are conflicting needs on many streets, including servicing and emergency access for large vehicles,

    it comes down to the expectations and aspirations of the design engineers, how do we reset their priorities? in a number of jobs where I’ve asked for better thinking, i.e. footpaths in car parks, I’ve only got the same old, basically, how can we clone Max?

    • Steve D

      The roadway in my street is about 7 metres, kerb to kerb, with cars parked down one side most of the time, and many people still drive down it at 50 to 60 like utter nutjobs. Traffic calming is important for roads that are truly overbuilt. But we do need to get away from the expectation that most people have, which is that “50″-but-really-60 is the speed you’re supposed to be driving, and you should do everything in your power to achieve it, wherever you are.

      Having a blanket 30km/h limit that covers the large majority of the city, and enforcement to back it up, will help people keep to a habit of driving at 30 km/h on residential streets. At the moment lower limits are few and far between, so people aren’t in the habit of driving that slowly, and resent the unusual disruption to their normal driving rhythm.

      A recent post right here had the statistic that average free speeds on urban roads have dropped from 57km/h to 51km/h since 1995. That’s when there are no traffic lights, no obstructions, no traffic calming, no congestion, etc. It’s the speed people choose to drive when they can go as fast as they like. What caused it? Surely enforcement has got to be a big part of the reason for that.

  • Sacha

    The current 4kmh tolerance campaign might show the impact of enforcement alone. And it must be possible to model some actual cross-town trips from end to end at both 50 and 30kmh maximums and verify the difference in travel time.

  • Braw

    Excellent post NCD with some compelling arguments. These are exactly the kind of bold (but sensible) moves that Auckland needs to take if we’re going to have any hope of moving up the world liveability rankings. Let’s do it!

  • Nice post NCD, some good points raised. Yes, I would dispute the absolute pedestrian fatality risk numbers, as your figures are from a 14-year-old reference based on even older data (some from the 1970s); we’ve come a long way since then in terms of vehicle frontal design, emergency medical care, and correct analysis of the fatality data. Quite a number of more recent studies have put the typical fatality likelihoods at 50km/h at ~20-30% (or less). But you’re very right right that in all cases the *relative* risk from 30k to 40k to 50k tends to double or treble; so it’s a very good reason to bring down travel speeds.

  • JimboJones

    I think 40kph is a more reasonable change. 40kmh the default in a built up area, 50kph the exception on selected arterials, and potentially 30kmh in Auckland city and other pedestrian areas.

  • SF Lauren

    Now given 77 pedestrians died on london roads in 2011, 58 in 2010. Based on the above story some 640 will be created out of nothing if they put a 30km/h speed limit over the entire city.

    It would seem there is something wrong with the numbers if 700 lives can be saved from the current 60 or so deaths.

    • Dear me, you do have very poor reading comprehension don’t you. The research refers to deaths caused by automotive accidents in London, not sure why you decided they were talking about pedestrians alone.

      To recap, they estimated the existing low speed zones were already saving 200 lives a year from car crashes, while if they rolled them out citywide they would save 500 more.

      Try reading the paper before trying to critique its findings.

  • NCD

    Thanks. Here’s a pic from the study linked to above by Max/Bryce

    Seems quite robust. Dotted lines are at the confidence bounds. Relative risk: about 5 times more likely to die at 50 than 30km/hr.

  • Don C

    We could save more lives if all cyclists would obey the law and wear helmets…. But of course some like Patrick think they know better.

    • Way to completely miss the point as always Phil. She was training for an event way out of town. No one is saying that someone doing that kind of cycling shouldn’t be wearing a helmet. That is completely different to someone who might be cruising around a few quiet streets to get to their local shops.

      As for Patrick, I see him carrying his helmet around with him

    • bbc

      So should all car drivers wear fire retardant suits and crash helmets like car racers? That would likely save lives too, why should cyclists be subjected to such rules and car drivers not? Not all cyclists are competing in races in a velodrome.

      • bbc

        That article is the typical rubbish published in NZ about people on bikes, take an extreme and use that as proof that all cyclists should have helmets.

  • Mark Todd

    The point you all miss is every time you advocate removing the cycle helmet law you are risking someone’s life. As adults you should know better!
    It takes seconds to put a bike lid on, it is no discomfort or hassle to wear one, and they save lives. Only a moron would cycle without one.

    • Bryce P

      Every time you hop in your car you are not only risking your life but the lives of others. I assume you have never driven over the posted speed limit, even by a few km/h? Or let kids climb trees? Or a climbing playground? All involve risk. It is how we determine if the risk level is appropriate or not. If we were really worried about the road toll in NZ we would be building median barriers down every road with a State Highway designation and dropping the speed limit on other roads to a max of 80 km/h, but then of course you would feel inconvenienced.

    • Interesting to look at ACC figures on Head injury costs ( if you’re interested):
      – On-road Motor veh accs: 21% of all claim costs
      – On-road Cycling accs: 9% of all claim costs (off-road % is lower, interestingly)
      Seems that helmets in cars would be very sensible; clearly seatbelts and airbags aren’t enough. It takes seconds to put a car lid on, it is no discomfort or hassle to wear one, and they save lives. Only a moron would drive without one…

  • Sacha

    Herald story on policing the new 4kmh limit notes that pedestrians make up way more of the transport fatalities in Auckland than other parts of NZ –

    Strangely enough cyclists do not seem to be the problem.

  • bbc

    Quit SPAMing with reactionary inflammatory comments

  • Interesting that in the Netherlands, where EVERYone cycles, but, correspondingly, NO ONE wears a helmet. What are their stats on death by bike like?

  • Sacha

    How many pedestrian injuries and deaths are caused by cyclists? I thought so. Enough with the derail.

  • Mark Todd

    So the good people of the transport blog are now deleting posts that have links to head injury safety stats… Shame on you as you never know, someone could read those stats, decide to buy and use a cycle helmet and survive a head injury. Congratulations to you for putting your own agenda before saving lives :(

    • Sacha

      Mark, most blogs automatically put you in a moderation queue if your comment contains multiple links. I wouldn’t assume anything has been deleted just yet.

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