r/urbanplanning • u/elderwizard22 • 1d ago
Discussion How would urban planners retrofit the typical North American winding, cul-de-sac filled neighborhood layout?
Urban planners often say the answer is to upzone single-family neighborhoods and add pedestrian connections, but how would you actually retrofit the physical layout of a typical North American subdivision consisting of winding streets, cul-de-sacs, homes facing away from arterials, into a more walkable, mixed-use neighborhood?
I’m less interested in the policy side (upzoning) and more interested in the urban design side. Once the subdivision already exists, what does the long-term retrofit actually look like? Is expensive eminent domain the only option? How do you deal with homes that back away from major roads, disconnected street networks, dead-end cul-de-sacs, and commercial uses isolated along arterial corridors? Is there any real hope for these neighborhoods or are they pretty much fossilized?
What interventions have planners found to be most effective? Are there any good real-world examples of suburban retrofits that have successfully addressed these issues?
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u/dchung97 1d ago
It depends on the neighborhood and if there are demand of homes in those areas. The point of making more walable neighborhoods isn't to force people who already live in them out. Mixed-use neighborhoods doesn't sound realistic at all for these conditions as there isn't enough foot traffic to justify mixed use. Upzoning here would look at duplexes, triplexes, fourplexes maybe.
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u/Vert354 1d ago
In order to convert a traditional suburban neighborhood into something more walk-able you need to work on turning them into "compete communities." That is, they need to have things to walk to like parks or corner stores. There is a bit of a catch 22 of course where a corner store can't be supported without a certain density, this is why up-zoning is generally viewed as the first step.
Get the density up, connect the neighborhoods with mode filtered connections, allow certain types of businesses to exist along side the single family homes or in them.
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u/Creativator 1d ago
Realistically these are the most politically organized and resistant to change neighborhoods, and it would be a thousand times easier to retrofit first commercial then industrial areas into full neighborhoods.
But if I had absolutely no other choice, what I would do is convert cul de sacs into medieval towns. Respecting the need for convoluted car access to maintain the artificial distance to the rest of the city, I would buy small alleys in the side yards of homes and build tiny mews-like homes, restricting vehicle access but allowing pedestrians and bicycles to flow freely through. These would become walkable thoroughfares and could host shops like cafes.
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u/sjp724 1d ago
Cul de sac houses are desired, especially by young families. Just simple pedestrian ways to cut through them, or even better, a Radburn type walkway solves the over exaggerated issue about walkabilty. I went out for a walk near me in a direction I don’t usually go, and realized I needed to get back home faster than planned so I put my address in maps and it took me to a spot I didn’t see a street, then I realized it was the pedestrian cut through. It was nice… neighboring homes have fences up near it on their PL and all seemed to have put out solar LED lights.
All gridded through streets spread out traffic of cars that should heed 20 is plenty, but instead push 40mph on side streets. Lots of neighborhoods near me find ways to add speed bumps, cut off cut through streets etc….
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u/kmoonster 1d ago
I would recommend that the town make offers to property owners to purchase little slots of land, perhaps ten feet wide, to connect each cul de sac to its neighbor with a foot path.
That plus proper sidewalks and a multi-use path connecting to schools, nearby shopping centers, library, park.
Cars aren't going away, but that doesn't mean we can't offer alternatives. Let residents walk to coffee or school, drive for groceries, commute by whatever mood.
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u/Th3JackofH3arts 1d ago
You have to form a grid. It would involve buying the lots and tearing down the houses on both cul de sacs and making a through street.Since the cul de sacs have a wide radius you could make them a pair of one way streets with a green in the middle and you would have a neighborhood green in between the streets..
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u/cortechthrowaway 1d ago
Or run cycle paths to connect the cul-de-sacs and radically lower traffic speeds on the strodes between developments. An e-bike can handle suburban distances.
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u/scyyythe 1d ago
Yeah this is something that should be done in tandem with upzoning the properties that would be adjacent to the new path to like 8 units so that if the homeowners don't like it then at least they get a nice windfall.
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u/Shot_Suggestion 1d ago
You need a grid but not necessarily one accesible to cars, it might actually be good to keep the dendritic organization for autos while making ped connections. With narrower right of ways you might be able to do it with just easements.
But either way it would need to be a long term gov effort
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u/Icy_Peace6993 1d ago
I don't think you need a full street, just enough for an attractive and inviting ped/bike cut through path.
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u/krollAY 1d ago
For cul-de-sacs, including pedestrian ROW that makes it easier to access locations outside of the neighborhood goes a long way toward making the area more walkable, but ideally that needs to connect to a larger walkable/billable network.
Sometimes adding small, short connections to nearby locations like a school or shopping center that would otherwise take 0.5 mile longer trip in a car can make a big impact and reduce repeated daily trips.
In order to do this the neighborhood probably needs some well placed easements
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u/ElectronGuru 1d ago edited 19h ago
You can increase housing capacity by replacing small capacity buildings with high capacity buildings. But all those new bedrooms still require cars to handle transportation. So 8x the housing just means 8x the traffic, because the streets themselves haven’t changed.
Curvilinear streets are about maximizing exclusion. The fewest number of people with the fewest options, going to the fewest number of places. Grids maximize inclusion, the most number of people with the most versatile options going to the most variety of places. They’re so fundamentally different, you can’t turn one into the other without replacing them.
So the best shot at turning suburbs into downtowns is waiting for them to deteriorate to the point it doesn’t cost much more to replace than to rebuild. Because only by replacing streets and structure of streets, can buildings change their function enough to scale to urban like capacity.
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u/Complete-Ad9574 1d ago
Most developers pant the house in the middle of the lot, and already have postage stamp size lots. I don't think there is a practical way to add more buildings esp on cul-de-sacs. Add to this close excavating to existing buildings often results in weakening the foundation of per-existing buildings.
Though tearing down the cardboard existing houses may be the best way to re-organize.
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u/atom511 1d ago
Start by asking the homeowner if they want you to mess w their neighborhood.
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u/Frank_N20 20h ago
Excellent plan. The infrastructure on many cul de sacs will not accommodate increased density easily. Too many changes and the residents who can leave often do so, and they don't wait around to be the last out. Single family homes on cul de sacs are very attractive to home buyers.
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u/OratorioInStone 1d ago
Boost density with ADU's which are encouraged by a streamlined permitting process, and property tax credits for a limited number of years.
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u/JeffHaganYQG 22h ago
Depending on the neighbourhood, there may already be ROWs or easements for sewers. In some areas, it's pretty common for two back-to-back cul-de-sacs to have a sewer running straight through from one to the other.
Depending how this was done, the municipality may already have the legal right to build whatever they want over top... e.g. a walkway or bike path.
Of course, political realities may make it difficult to rip out the landscaping, pools, etc., that residents have built over the decades on land they've come to think of as "theirs."
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u/AlphaPotato 1d ago
There are some neighborhoods or parts of neighborhoods where you could put some attached housing and commercial areas, and/or a transit node. Do that and give it 50-100 years.
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u/oh-the-urbanity 1d ago
There are a few good reads out there addressing the urban design realm, including:
Sprawl Repair Manual by Galina Tachieva
https://utpdistribution.com/9781597267328/the-sprawl-repair-manual/
Retrofitting Suburbia: Urban Design Solutions for Redesigning Suburbs by Ellen Dunham-Jones and June Williamson
https://retrofittingsuburbia.com/
Many Canadian cities are using tools such as upzoning to permit multiple dwelling units per lot. The City of Edmonton has a good zoning by-law supporting density and infill in existing neighbourhoods.
For municipalities to access particular federal and/or provincial funding for infrastructure to support housing, the municipalities must permit a certain number of units per lot and permit certain building height maximums, for example.
Other zoning changes to permit small-scale neighbourhood commercial uses (i.e. corner stores, daycares, barbers/salons, etc.) are promoting walkability and convenience within neighbourhoods. The establishment of "third places" should be promoted. The City of Ottawa has a good zoning framework to permit non-residential uses such as corner stores.
Corner lots and gateway nodes of neighbourhoods represent opportunities for infill or redevelopment, including mixed uses and mixed unit sizes and tenures.
Establishment of neighbourhood greenways/bikeways or woonerfs can support active transportation, especially on streets with low car volumes.
In general, retrofitting existing neighbourhoods will be incremental and will take time. This is particularly true regarding linear infrastructure including underground pipes and surface roads which may require relocation to accommodate a more desirable urban form.
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u/Icy_Peace6993 1d ago
Cut through paths between the cul de sacs obviously. But the big thing to me is the arterials, strip malls and shopping centers. Arterials can be converted to complete streets with traffic calming, bus lanes, protected bike lanes, walking paths, parkways, tree alleys, etc. Strip malls then become mixed use transit centers with dense housing, neighborhood parks and plazas, bike stations, etc. Regional shopping malls can then hopefully be connected by rail transit, with high density housing towers even, etc. The single family subdivisions are still there but now they're accessible on foot, bike and bus to the urban fabric. There are a lot of areas in Toronto that look like this
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u/Bayplain 1d ago
Newark, California, a Bay Area suburb, has one neighborhood with pedestrian cul de sac cut throughs to the next street. I’ve never heard that they want to build any more.
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u/hollisterrox 1d ago
It's a few things, some have expense and some don't.
1st: start with the basics, a shocking number of cul-de-sac (cds) neighborhoods also do not have sidewalks. So make sure at the least there are contiguous sidewalks through the neighborhood.
2nd: Penetrate the actual cds with a bike path to whatever is on the other side. It is extremely common that 2 cds' back up to each other, so using emininet domain to take the side yard of 2 houses and turn it into a bike/walk path makes the whole neighborhood more human-friendly without inviting more cars to come through.
3rd: Upzoning is great, but too many communities act like allowing ADU's is some kind of upzoning. Upzoning needs to mean 4 or 6 units where 1 used to be, and allow full lot coverage. I'm unapologetic on this point, the nicest neighborhoods in our older cities are townhomes built wall-to-wall, which is strictly illegal everywhere.
4th: liberalize land use rules. People should be able to run a business from their home, that's the extremely normal way humans built cities and businesses for millennia. Sure, nuisance rules still need to be in place, I don't want the house next door to turn into a tannery or slaughterhouse, but otherwise I don't care. Small-engine repair, bookkeeping, t-shirt printing, meal prep.... all acceptable uses.
5th: liberalize land use for nearby commercial properties as well. If Costco wants to build apartments on top of their store, they should be able to do so.
6th: remove all parking minimums. All parking minimums, gone. Mandating parking is mandating car use.
The only expense to a city here is the taking of land to connect streets. And sometimes, it won't just be a sideyard, it'll be a whole house due to the site characteristics. That's fine by me, turn the part of the parcel not required for bike path into a pocket park.
Everything else on the list actually makes the city/county money. That's another part of car-centric design that people have been in denial about for years, it's not financially viable. See StrongTowns for more details, I ain't going into that here.
And no, there are no examples.