Lately I’ve been thinking about how to better join the dots between Auckland’s housing challenges and its transport challenges. We’re all familiar with the common stories about Auckland’s problems: Housing is too expensive, pricing young people out of the market and forcing low-income households into crowded or unhealthy accommodation. The transport system isn’t working as well as it could – key roads are congested, public transport is often unreliable due to our mid-century decision to eschew a rapid transit network, and walking and cycling often feels unsafe, again due to policy choices.
But it strikes me that we aren’t yet telling a clear story about how we could solve Auckland’s challenges. This is an attempt to tell some of that story.
It all starts with the street. When Auckland’s suburbs started to get built in the late 1800s, people did a few things to cut costs. One of those was providing long, narrow residential sites without back alleys or many cross streets. This left behind more saleable land while avoiding the need to provide stormwater or sewerage – people simply dug long-drops at the back of their long sites.
The result was a city that has a dearth of streets. The following map compares my neighbourhood in Auckland with my brother’s neighbourhood in Denver, Colorado – his is a bit further from the city centre but otherwise similar. Note the fine mesh of cross-streets and the closely-spaced arterial roads in Denver, and the spidery mesh in Auckland:
When we zoom out the map, the comparison gets even starker. Not only does Auckland lack a Denver-style street grid, it also has a regional transport network full of gaps and pinch-points caused by its position on two harbours.
This is exacerbated by the fact that we have recently built out most of the space in most designated motorway corridors. Once the Waterview Connection opens, the motorway network will be largely complete and will probably never be significantly expanded again, at least within the city. Contemplate that, for a moment.
In short, we are a growing city that lacks street space and has extremely constrained ability to add more transport corridors virtually anywhere in the city.
This brings me on to the second part of the story: Cars. Cars are wonderful things. They are the best way to get to the West Coast beaches, and the second-best way to get to urban beaches, after cycling. If it weren’t for home delivery, they would be the only way to buy a refrigerator or a tonne of compost for the garden. But we’re not going to be able to fit an ever-growing amount of them on Auckland’s roads at peak times. We don’t have the space for it.
In saying this, I’m not arguing that we should necessarily fear congestion. Auckland’s existing performance isn’t terrible: the aggregate cost of congestion is right about what you’d expect based on data from large Australian cities, and average commute times are reasonable. But the constrained nature of our street grid and regional motorway network leads me to think that it will tend to increase more rapidly as the city grows. Consequently, we will need to do something differently.
[A brief digression: We will face this problem regardless of where new residents end up living. Banning growth in your neighbourhood and insisting that all newcomers move to Drury will not solve the problem: many of those people will simply hop on the road to commute to jobs in the city or in the growing Auckland airport business park. Similarly, banning growth on the fringes won’t fix the problem either: many newcomers will still need to drive to get to jobs spread around the city.]
This leads directly to the third part of the story: What can we do instead, if the current approach won’t keep working?
Basically, there seem to be three things we can do.
One: We can implement congestion pricing – or, as Jarrett Walker calls it, a decongestion charge – to take the edge off peak-period delays on busy corridors. I’ve discussed this extensively in the past so won’t rehash this discussion here. One point that many people raise, though, is that congestion pricing should be paired with a strong focus on improving alternatives to driving, to allow people to avoid the charge.
Two: We need to improve Auckland’s regional rapid transit network to ensure that it is possible to travel longer distances within Auckland both quickly and reliably. Setting aside congestion pricing for a moment, rapid transit is the only way that we can reliably achieve this. If you want to travel 20 kilometres and get to work on time most days, you’re better off being in a train or a busway service than a car.
Rapid transit improvements are likely to be especially important for making greenfield growth work well. People who will soon be living in Dairy Flat, Whenuapai, and Drury can benefit from the option to access fast and reliable transport options.
However, good rapid transit isn’t simply a matter of building a busway out to the wops. Service integration is also essential. What that means is that buses or trains need to connect with each other at key points, offering easy and reliable transfers between services and access to a wider range of destinations. Interchanges like Otahuhu and Panmure are important, but the city centre is even more important, as it will always be the place where most of the lines converge.
In other words, if we want to make rapid transit work well for greenfields, we also need to sort out what’s happening to buses and trains downtown and in the inner urban areas.
Three: We need to improve Auckland’s urban cycleway network to give people new options for short- to medium-distance trips within the existing urban area. Cycling has a lot of unrealised potential in Auckland (and most New Zealand cities): At peak times on congested roads, a bicycle can get you to your destination faster than a car, and technological improvements (ebikes!) are flattening out the hills as we speak.
Getting more people cycling for everyday transport would go a long way to sorting out the transport challenges associated with new housing development in a city with a fragmented street grid. Every person who rides to the shops or to work is one who isn’t competing for road space and parking space. We will value those people more in the future.
A key barrier to cycling in Auckland is the perception that it is not safe. This doesn’t necessarily dissuade the mid-30s bloke in lycra, but it will keep many schoolkids, middle-aged women, and a whole bunch of other people off their bikes. We can fix this – and get people from ages 8 to 80 cycling – by designing streets better and providing safe cycling infrastructure where it’s most needed.
To summarise: Auckland’s built itself into a bit of a hole, and in order to meet the needs of a growing city, it will have to do things differently. That means congestion pricing (to make the road network work better), a really good regional rapid transit network (to ensure fast and reliable journeys throughout the urban area), and a safe, joined-up network of urban cycleways (to give people more options for shorter trips). This shouldn’t be seen as an alternative that we could pursue once we’re done building motorways: it is now the most realistic way forward for the city.
What do you think Auckland should do in order to address its growth challenges?
Vincent and Pitt, Thursday 5:49 pm. Every corner occupied with people wanting to cross, including eight on this silly little delight of a ‘pedestrian refuge’, or nine if you include me, as I stepped back into the vehicle priority slip lane to take the shot, including at least one genuine princess. There appears to be one vehicle using the intersection and another a long long way in the distance up Pitt street.
Auckland Transport have a lot of work to do to fix the dated modal priority that dominates City Centre streets as it is no longer fit for purpose. This design dates from a time when very few lived in the city, fewer worked there and those that did didn’t stay on to recreate in the city either. It is also from before the time that the economic and social value of well designed walkable streets were so well understood. People not in cars need more space and time afforded to them from the people that control this critical part of our public domain. The value of this in supporting the modern urban services economy and the social well being of everyone is overwhelming.
After all transport infrastructure is simply a means to economic and social ends; not an end in it self.
The current cycleway revolution in Auckland has a serendipitous feature for one of Auckland’s most cherished but badly treated areas: All routes lead to Karangahape Rd. Both the recent city by-passes: Grafton Gully and the Pink Path, have one end in the K Rd precinct, our only current cycling ‘superhighway’, the NorthWestern, is about to get its city termination moved forward from Newton Rd to the K, and the coming real on-road separated cycle lanes on Great North Rd also lead straight to the K. Oh and the cycle friendly ridge level link of our very own Pont Neuf, Grafton Bridge, leads bike riders there from the other end.
Yes Karangahape Rd is the ground zero of Auckland’s bike riding revival which surely offers a real opportunity for the area to at last both thrive and remain true to its very specific identity. It would be a shame for K Rd to either slide back into decline or to try to keep up with its glossier rivals by seeking to become something its not. And as Ponsonby Rd becomes ever more upmarket and seemingly determined to drown itself in more and more parking and therefore driving, this offers K Rd a great opportunity to brand itself as a street and people place and not a car place. This happy confluence of street culture and improving bike infrastructure is already having an effect on the numbers that access businesses on the street by bike, as can be seen below:
And in the data:
But this is despite the lack of any safe cycle routes on K Rd itself, nor clearly enough parking places. But happily our Transport Agency is on it:
The plan is to add cycle lanes each side with temporary barriers, or at least without expensive excavations of the existing curb line and stormwater systems. And improved bus priority which is already clearly vital to the area. It is wise to start with a changeable pattern as there is a longer term opportunity to further tune down through traffic once the CRL station opens way off in 2023. Then this important section, between Pitt and Queen Sts should become one lane each way for buses (and emergency) and otherwise be for people on foot and bikes only. For more on the plan and links to make a submission go here.
To this end I think the K Rd business association should push for a regular traffic closure of this short section between Pitt and Queen every Sunday. This won’t be particularly disruptive, except to through traffic, and that should be the desired outcome; an assertion over place through movement. And of course a way to brand the area as street not arterial, and uniquely street.
So the whole upgrade is clearly a great opportunity for the businesses in the area to market themselves as being at the leading edge of the new city with the bike as the symbol of all the current new urban changes underway: The rise in city centre living, the ongoing revolution in Rapid Transit ridership, in short the return of the City.
The wider point is that the driving era destroyed this place and the walking/biking/transit age we are now in is its best chance at redemption. Go the K.
From the significant disruption of building the City Rail Link we get two huge benefits. First and foremost, we get a tunnel that transforms our rail network and allow significantly more people to travel around the region free of congestion. But for many of our city streets, it also delivers us blank slate from which we can deliver on the visions that have already been created for the future of the city. It is an opportunity too important to waste. And yet as we highlighted last week, Auckland Transport seem determined to waste that opportunity with their awful plans Albert St and the roads that cross it.
At their heart, AT’s plans once again show that many transport engineers and institutions seem to desperately cling to the belief that their role is to find ways of accommodating a set (and growing) level of traffic demand. In doing so they often fail to recognise that drivers respond to road network provided to them.
Adding traffic lanes and supersizing intersections is almost always a vain attempt to ‘solve congestion’. But any relief is normally only short lived because traffic tends to act like a gas, expanding to fill any space made available to it. Conversely it has now been seen time and time again that removing capacity from the road network results in traffic melting away as drivers respond to the changes.
Some of the most famous examples worldwide have been the removal of an elevated highway and restoration of the stream under it in Cheonggyecheon, Seoul, the removal of the Embarcadero Freeway in San Francisco after it collapsed in the Loma Preita earthquake and recently Paris has permanently closed off a section of road along a bank of the Seine. These have actually resulted in net reductions in vehicle numbers as drivers find alternative routes or change how and when they travel.
Back here in Auckland we now have our own real life experiment underway right now thanks to the works to construct the CRL. Parts of Albert, Customs, Victoria, Wellesley and Wyndham Streets are currently shadows of their former selves having been narrowed down for works, in some cases significantly. An example of this is highlighted well by the image from my post the other day on the construction progress of the City Rail Link looking at the Albert/Customs/Fanshawe intersection. As you can see:
- Albert St south of the intersection has been narrowed down to just one lane southbound with the other five lanes closed off for construction works.
- Albert St north of the intersection only allows for vehicles to travel northbound. The southbound lanes are closed due to the proximity to the under demolition Downtown site.
- Customs St has also been narrowed down to just one lane each way through the intersection. Previously there were three lanes westbound and two eastbound.
While the works are the scale they are for a reason, in many locations AT also appear to have adopted a policy of trying to minimise disruption for motorists resulting in footpaths that have been cut back and pedestrian phases changed to provide as much capacity for cars as they can. Yet for months now Auckland Transport have pushed the message that people need to change how they travel to avoid carmegeddon including through the use of Jerome Kaino to help push the message.
Based on results so far, I think we can say that Auckland Transport’s message has got through and/or that we’re seeing the same result as those examples mentioned earlier. This is because one of the most notable outcomes from the works so far has been a lack of major traffic issues. Peak time congestion doesn’t appear to be any worse than it was before the works started and during the day these roads can still be eerily empty, as this picture from looking South of Wellesley shows.
These works and previous city centre improvements show that the drivers will adapt to changes, that the city doesn’t grind to a halt. It confirms we can shape or city to promote more of the things we want and less of the things we don’t.
Therefore we believe we need to start looking differently at how we approach roads in the city centre. In some cases, plans that even a few years ago were considered visionary or even just “the best we could hope for” are now starting to look tame. We need to completely rethink how we approach space in the city centre and we can start but looking overseas.
Most great cities that we look to have come to realise that right priority for transport in cities is something like below.
We need to start thinking the same way too. And not just on those streets most directly affected by the CRL works. Take Customs St as an example. In places it is currently up to seven lanes wide. The City East-West Transport Study (CEWT) suggested the pedestrian space increase a little bit but that there would still be at least three lanes each way.
Yet the image above shows that at one location at least, Customs St has been reduced to just one lane each way and last time I looked the sky was still well above my head. Perhaps it’s time to go back to the drawing board and rethink what we want for the city. Let’s be bolder and perhaps start by answering questions like:
- Do we really need four general traffic lanes on Customs St?
- Do we need traffic on Quay St at all?
- How soon can we pull down the awful Hobson St flyover?
- Can we be bolder in how we redesign Hobson and Nelson Streets, including returning them to two way streets?
- Why do we still even have cars in Queen St?
- Can we make Fanshawe St less like a motorway sewer?
We obviously can’t do everything at once what the CRL works perfectly show is that drivers will adapt, that the sky won’t fall so we might as well be bold and design a world-class city. And of course until we can deliver that bold design, we can always start by trialling it New York style with some planters and temporary solutions.
Hello, and welcome back to Sunday Reading. Here are a collection of articles, videos and commentary I found interesting over the week. Please add your own links in the comments section.
Here is a good article on the illogic of sprawl from a fiscal standpoint. Nice to see Chuck Marohn and Strongtowns mentioned. Matthew Robare, “Why Sprawl Is Not the Only Choice“, The American Conservative.
Sprawl isn’t really as cheap as it seems. A network of tax breaks, financial guarantees, subsidies, and other chicanery keep parts of suburbia relatively inexpensive. Most notably, transportation costs are often excluded from the discussion of housing affordability, even though it’s hard to live anywhere without a way to get to work. For example, Chuck Marohn at Strong Towns has shown that the low density, car-dependent development that has typified American cities since World War II does not produce enough tax revenue to service the debt that cities took out to build the infrastructure needed for sprawl.
The numbers stuff can be really dull and become a barrier for some to the advantages of urbanism. Sightline recommends the housing and urbanism message can be better communicated by focusing on people, and a shared community challenge. City Observatory says not so fast, here’s a ‘teachable moment’ about supply and demand. Joe Cortright , “Lessons in Supply and Demand: Housing Market Edition“, City Observatory.
The demand for cities and for great urban neighborhoods is exploding. Americans of all ages, but especially well-educated young adults are increasingly choosing to live in cities. And in the face of that demand, our ability to build more such neighborhoods and to expand housing in the ones that we already have is profoundly limited, both by the relative slowness of housing construction (relative to demand changes), and also because of misguided public policies that constrain our ability to build housing in the places where people most want to live, to the point in many communities, we’ve simply made it illegal to build the dense, mixed-use, walkable neighborhoods that widely regarded as the most desirable.
We don’t expect the demand for urban living to abate any time soon–in fact, there’s good reason to believe that it will continue to increase. And it’s still the case that we have a raft of public policies – from restrictions on apartment construction and density, to limits on mixed use development, to onerous parking requirements, and discretionary, hyper-local approval processes – that make it hugely difficult to build new housing in the places where it’s most needed.
Many of the problems we encounter in the housing market are a product of self-inflicted wounds that are based on naive and contradictory ideas about how the world works. We believe that housing should both be affordable and a great investment (which is an impossible contradiction), and we tend to think the laws of supply and demand somehow don’t apply to one of the biggest sectors of the economy (housing). At their root, our housing problems–and their solutions–are about understanding the economics at work here. So in our view, it’s definitely time to talk about supply and demand.
Here’s George Monbiot stating the obvious – “it was a mistake – a monumental, world-class mistake”– “Our roads are choked. We’re on the verge of carmageddon“, The Guardian.
Over half the car journeys people make in this country are less than five miles: this is what policy failure looks like. Why don’t people cycle instead? Perhaps because, though the number of motorists killed or seriously injured has fallen sharply, the number of cyclists killed or hurt on the roads has climbed since 2003. This now accounts for 14% of all casualties, though cycling amounts to only 1% of the distance we travel.
The simplest, cheapest and healthiest solution to congestion is blocked by the failure to provide safe transit. Last year the transport department crowed that it could cut £23m from its budget as a result of an “underspend on the Cycle Cities Ambition budget”. Instead of handing this money back to the Treasury, it should have discovered why it wasn’t spent, and ensured that it doesn’t happen again.
So here’s a novel idea: how about a 21st-century transport system for the 21st century? Helsinki is making public transport as convenient and flexible as private transport. For example, by aggregating people’s requests via a smartphone app, minibus services can collect people from their homes and deliver them close to their destinations while minimising their routes. Hamburg is building a network of cycling and walking paths so safe, pleasant and convenient that no one with the ability to do otherwise would want to take a car.
Here is Lyft founder John Zimmer describing how technology will solve the problem of the car in the city – “The Third Transportation Revolution“, Medium.
Next time you walk outside, pay really close attention to the space around you. Look at how much land is devoted to cars — and nothing else. How much space parked cars take up lining both sides of the street, and how much of our cities go unused covered by parking lots.
It becomes obvious, we’ve built our communities entirely around cars. And for the most part, we’ve built them for cars that aren’t even moving.
…I believe we’re on the cusp of nothing short of a transportation revolution — one that will shape the future of our communities. And it is within our collective responsibility to ensure this is done in a way that improves quality of life for everyone.
By 2025, private car ownership will all-but end in major U.S. cities.
Baffingly, our human habitat remains under examined. What make great places, streets and cities? Here is a comprehensive study that tracks people’s movements to determine the properties that make more healthy and active places. It appears consistent with other studies by Reid Ewing and others. Kaid Benfield, “Four Characteristics of Active, Healthy Neighborhoods“, Placemakers.
- Residential density. It takes a critical mass of homes in a neighborhood to support economically viable shops and amenities within walking distance.
- Intersection density. Well-connected streets tend to shorten travel distances and put more likely destinations within walking distance.
- Public transport density. More transit stops within walking distance make it more likely that residents have transit options and will elect to use them.
- Access to parks. Parks serve not only as places where people exercise but also as destinations people walk to and from, getting exercise as they do.
Here’s a fascinating study on the health value of architectural features that encourage social contact- porches, stoops, etc. This seems so basic, but rarely applied in New Zealand. Brown, SC et al, “Built environment and physical functioning in Hispanic elders: the role of ‘eyes on the street‘”, Pub Med.gov.
After controlling for age, sex, and income, architectural features of the built environment theorized to facilitate visual and social contact had a significant direct relationship with elders’ physical functioning as measured 3 years later, and an indirect relationship through social support and psychological distress. Further binomial regression analyses suggested that elders living on blocks marked by low levels of positive front entrance features were 2.7 times as likely to have subsequent poor levels of physical functioning, compared with elders living on blocks with a greater number of positive front entrance features [b = 0.99; chi(2) (1 df) = 3.71; p = 0.05; 95% confidence interval, 1.0-7.3].
Street party. Balmoral, Auckland, 2015
While many of our streets are designed for social interaction and access to transport services, people seem largely content to live behind stone walls and high hedges. Here’s a neat story from the suburbs of Minnesota that has encouraged people to come back to their front yards. James Walsh, “Project connects St. Paul neighbors by moving them to their front yards“, Star Tribune.
Ross Callahan has lived in his Rondo-area home for 14 years. Yet, he admits, he’d communicated with only a few of his neighbors over that time, usually with a nod or a wave.
Then a funny thing happened. He started spending time in the front yard.
Thanks to a project designed to get people out of their backyards and meeting their neighbors, Callahan started cleaning up the green space at the center of his cul-de-sac, laid a new patio and, yes, started getting to know the people who live in the dozen homes around him.
In a bid to show that it’s possible to transform streets to be more people friendly a Brazilian urban planning group has scoured Google Streetview to put together examples of change. They currently have over 35o examples including a number from Auckland such as the shared spaces and Jellicoe St.
Here are a few examples but of course there are many many more
Ferenciek Tere, Budapest, Hungry
Av. Duque de Ávila, Lisbon, Portugal
Vester Voldgrade, Copenhagen, Denmark
Rue Rt. Hubert, Montreal, Canada
The results show just how much better it is possible to make our streets – and collated shows the work is a fantastic resource.
Several months back, I took a look at the way we’re designing street networks and neighbourhoods in greenfield subdivisions. It’s not a pretty picture. The reigning assumption seems to be that places on the edge of the city are car-dependent now and will be car-dependent forever. As a result, developers and planners build places where it’s difficult to walk, cycle, or take a bus.
In my view, this ignores the reality that today’s fringe suburbs are tomorrow’s urban fabric. That’s nicely illustrated in this map from the Auckland Plan, which shows how the city has expanded since 1840. Suburbs built in the 1950s and 1960s are now firmly in the midst of the city.
In other words, urban growth wouldn’t be a problem if it weren’t for the fact that it is often pathological from a transport perspective – i.e. a developer goes to the edge of town and builds a bunch of cul-de-sacs, single use suburbs, and non-connective street networks, under the assumption that it will be a car-based place forever. Then somebody else comes along and develops the next paddock, and before long you’ve got this unworkable mess in the middle of an urban fabric.
In my previous post on the topic, I took a look at some research into how we can transform car-dependent suburbs into workable urban places. Here’s one such design from Galina Tachieva’s Sprawl Repair Manual. It’s a great idea, but it would require the purchase and demolition of 5-10% of the houses in the neighbourhood. The end result would be a net increase in dwellings as sites are redeveloped, but I can’t imagine it would be easy to implement.
Wouldn’t it be better to simply do it right the first time?
Now, I’m no urban designer, but it seems like there could be a role for strengthened structure planning in greenfield areas. This could entail, for example, local governments establishing (and rigorously enforcing) structure plans for street networks and street designs in new developments. The aim would be to ensure that streets functioned well for all modes of transport, rather than just cars, and that they didn’t create any “holes” in the urban fabric that would be difficult to travel through later on.
There are a number of great examples from the Netherlands, but I figured that it would be good to highlight some local examples where people are taking steps in the right direction. I haven’t comprehensively surveyed new developments, so I can’s say how representative these examples are.
First, here’s the development plan for Hobsonville Point. Hobsonville’s quite interesting as it’s conceived as a mixed-density, mixed-use place with a ferry connection. Here’s the plan for the street network at the Point itself:
The street cross-sections seem to be designed in emulation of the city’s most successful urban/suburban places – with street trees and relatively narrow lanes (by Auckland standards, at least). The two “boulevard” sections (red lines on the above map) are designed with 1.8 metre cycle lanes. It would obviously be better to have safe, separated cycleways, but hey, it’s a start:
A bit further west, at a Special Housing Area site in Whenuapai, they seem to be going one step further and installing separated cycle lanes on two major streets from the get-go. (All images are from the plan change released by Auckland Council the other week.) Although Whenuapai is following the classic “boxes in a paddock” model of suburban development in Auckland, it seems to be aspiring to something a bit different on the transport front. Here’s the map of the development:
It’s a bit difficult to understand how all of this will fit together without knowing more about proposed street networks for surrounding areas. The streets within the SHA seem like they may be quite wide, without consistent cycle provision. But take a look at the street cross-sections for the main arterials, Brigham Creek Rd and Totara Rd. They will have safe separated cycleways from the start:
Of course, a few cycleways in new subdivisions will not compensate for the street design mistakes made in previous developments. If you start riding the Brigham Creek Rd cycleway, you’re probably going to be mixing it up with traffic on some pretty inhospitable roads before long. That will take time to fix. But I’m hopeful that these projects are an indicator that we are in the process of overcoming our pathological approach to street design in new subdivisions.
Lastly, I’m aware that I’ve mainly talked about cycle design here, and omitted public transport. That’s because safe cycle facilities are particularly easy to install in advance, and challenging to retrofit. (Once people have moved in, adding cycle lanes means taking away their essential human right to free on-street parking – cue uproar!) But we also need to ensure that the area is served with good rapid transit choices, as proposed in the Congestion Free Network.
Given the growth out near Hobsonville and Whenuapai, perhaps we should be talking about accelerating the installation of busways on state highways 16 and 18? I honestly can’t see those areas working, long-term, without congestion free transport options:
What do you think about street design in new subdivisions? How could we do things better?
A few weeks back Peter had an interesting post about retrofitting Albany. In his post he suggested that we know that certain neighbourhood street networks lead to better urban outcomes. They are more walkable and easier to serve by public transport, etc. – yet, we continue to churn out dysfunctional neighbourhoods.
Zooming in a bit lower from the neighbourhood structure, I thought it would be useful to consider what we know about residential streets. Here is a list of features of residential streets that are often considered desirable features:
- Narrow widths,
- Short blocks,
- Continuous street trees (between the footpath and kerb),
- On street parking that is often occupied,
- Lots of intersections, preferably X-type.
Lets take a closer look at narrow streets. While outdated road manuals tend to require wider lane dimensions, more sweeping curves, and clear sightlines, we know that that these designs increase vehicle speeds, increase stopping distances, and lead to more crashes as well as more severe crashes.
Narrow streets, in particular ones with parked cars and continuous street trees, slow vehicles. This is something that can be observed by using the street and experiencing how the geometry and complexities require much more attention which in turn slows drivers.
We know that narrow and slower streets lead to safer streets. A study surveying 6000 streets in Longmont, Colorado, (Residential Street Typology and Injury Accident Frequency) found:
“As street widths widen, accidents per mile per year increases exponentially, and the safest residential street width are the narrowest (curb face).”
Specifically they found that a typical 36-foot (11m) wide residential street has a 487 percent increase in accident rates compared to 24-foot (7.3) street.
Regression analysis showing the number of crashes by street width.
Here is an 11 metre wide street in Favona (Mckinstry Ave). It is representative of a 1970s-era neighbourhood street in Auckland. This street type is common across Auckland and New Zealand.
The most dangerous street type – 11m
And below is a 7.3m wide street in Balmoral/Mt Eden.
The safest street – 7.3m
The following is a quick look at the accident data of those particular streets over the last 15 years from the NZTA CAS database. This is a screenshot of crash data in the Mt Eden neighbourhood north of Balmoral Road.
CAS crash data (NZTA) Red= fatal, Yellow= Severe, Blue = minor injury
Looking at the residential streets (not Dominion or Sandringham Roads) there are very few (11) crashes and all are classed minor injury.
Here is the same scale screenshot of the Favona neighbourhood.
CAS crash data (NZTA) Red= fatal, Yellow= Severe, Blue = minor injury
What stands out immediately is the sparse and branching street network. The difficulty in providing public transport and the requirement for car ownership and associated carparking space represents an unfunded liability both for the residents of this area and the rest of the city.
Another liability is the safety issue associated with these types of streets.
Not counting Buckland Road (it’s an arterial), the equivalent study area has about 12 minor injury crashes, but significantly one fatal crash on Mckinstry Ave.
This unscientific snapshot seems to be consistent with the Longmont research. At some point I’ll run a GIS analysis of the crash data to test international research.
Besides confirming what we know, it would be good to start developing solutions to make these wide and curvey streets safer, and of course to stop building them like this in the first place.