Portland & Detroit comparison is a bit laughable. May be we'll see this one day, but I'll believe it when I see it.
I live in a suburban area in a town of 30k.
A car centric 15 minute city is literally impossible. There will always be too much congestion to get anywhere in 15 minutes since cars take up too much space.
My work is ~13 minutes away. There is a Primary and Secondary School within 5 and 20 minutes walk. A supermarket is a 10 minute bike ride away. A hospital is 10 minutes drive away. A top 50 ranked University is 25 minutes drive away.
There is a good question from w-j-w that has been deleted here. Yes - it's a 15 minute car city at 8:30 AM. My commute goes to about 14 minutes...
This is on the days when I'm not WFH - which should also be factored in.
The guy has been dead for nearly one hundred years and the city still hasn't assigned a replacement urban planner...
Some commutes are more like 30 minutes (by car) or 40 at a bad time. But this is where someone has chosen to live at the opposite end of the city to their workplace, which is largely unnecessary.
I myself walk to and from work (when not WFH) and it takes around 20 minutes.
Can confirm it is a 20 minute city with your own car/motorbike/bicycle-enthusiasm (year round in 35 degree heat or -7 degree cold). The arterial roads are good and the bicycle pathways are pretty good in any area established before self government.
The new suburbs suck, and if you need public transport it is a tram line that services a single area and buses everywhere else. Live in a new suburb and have to rely on public transport? Sucks to be you...
Pretty good if you have a car/motorbike/bicycle-enthusiasm though. s/ Just choose not to be disabled or too old to drive.../s
The downtown in my city is by far the most dense and walkable area of town while still being far more accommodating for car drivers than any of the areas that have been newly revitalized for walkability. The main difference is the existence of ample parking shelters where the main (st)roads hit downtown, unlike the new areas that insist on only having street parking to intentionally limit the number of cars. Both approaches allow the area to be designed for walkability first. But the former does a better job at accommodating people who don't live within 15-minutes by walking or public transit, and does a better job at keeping cars from being a nuisance. Because the motorists have a convenient place to park and walk they do so, while street parking only forces the cars into the walkable streets(and surrounding neighborhoods) to circle endlessly looking for a place to park and increasing congestion.
I really like the strong-towns framing of delineating roads vs streets which are designed for cars and pedestrians respectively. I think too many people are quick to jump on the assumption that roads==bad and streets==good, when having good roads and parking structures can relieve the pressure and allow your streets to be streets. At least in the short-term, and in the long-term you are going to want to keeps some sort of arterial land strips for public transit use (in all but the most dense areas which can support subways). So making them roads now with a mix of buses and cars that gradually becomes more buses, and then possibly dedicated public transit makes for a good growth plan.
I think getting to places by car is often not the hardest part. Instead, the hard part (at least from a user's perspective!) is storing all the cars for all the inhabitants of the city, both at their origin and their destination. This creates ballooning space requirements, including duplication of space (much residential parking will remain largely unused during the day, and much business parking will remain largely unused at night). Then, even after devoting as much space to cars as US cities do, one winds up unable to plan simply to drive to one's destination, but having also to devote significant planning to parking.
The issue is that this will not scale. The space needed for cars scales at a different rate than the space needed for people, so does the infrastructure.
Today I live for a decade in one of the biggest cities in Germany (a still quite car centric nation by European standards). I never owned a car in that city and never missed it. If I need one for the hardware store I can just get a car sharing one. I spent maybe 100 Euros on car and gas every year.
Most of what I need for my daily life is within walking radius (grocery store across the street, hairdresser, 24/7 drinks and cigarettes, some restaurants and bars on the street, the rehearsal space for my band is a 5 min walk where I don't have to cross a single road). It is quite silent in my area and the air is good (no dust/grime on the balcony).
If my area was car centric I'd have to sacrifice all of that. But what would I gain in return? The ability to go to all the places I can already go to by subway, S-Bahn, bus or bicycle? No thanks, I'd rather have my city human-sized than car-sized.
Not when you account for congestion. Let's pretend that the average driver can accept sitting in traffic for one hour daily, or 30 minutes one way. What happens then is that more and more people will take the car until it's just congested enough to take 30 minutes to go somewhere -- even if the distance at full speed is just 15 minutes.
If you increase capacity more people will take the car until the trip takes 30 minutes again.
This just doesn't happen with less massive modes of transport because accommodating practically infinite amounts of foot traffic requires, comparatively speaking, very little area. Distances have to be shorter, yes, but scaling at a lower rate.
If anyone is interested here is great video on [Autoluw](https://www.youtube.com/watch?v=GlXNVnftaNs). This is what US needs, but I dont see this happening due america's car-centric culture.
In a comparatively-suburban "city", it's absolutely possible and probably fairly common. Of course, you'll likely have to leave the city far more frequently, and those trips may take longer than 15 minutes. By contrast, you could easily spend your entire life in New York without ever leaving city limits.
I think it's one of the better options in N/A outside of NYC, Boston and places in Canada (especially Quebec City and Montreal) - Boulder also often comes up in discussion though I've never been.
Comparing these to European cities which weren't leveled in WW2 is insane though - when pedestrians are first class citizens cities are absolutely wonderful to live in.
I imagine they'll drastically reduce parking needs, opening space for traffic lanes (reduce congestion) and commercial/services areas (make things closer to home).
I'm not even sure it is possible to satisfy this demand in a city. Houston has 26-lane highways and they are still building more roads to handle traffic. LA uses 14% of all land for car parking and is still building more parking spots. I suppose there must be a theoretical upper bound past which building more space for cars does not eventually induce more driving, but I know of no city that has reached that limit.
It's not like the south is a lost cause, improvement can still be made.
Heck, there is a subartic city in Finland with 12% cycling share, which is a lot higher than pretty much any city in North America. https://www.euronews.com/my-europe/amp/2021/01/22/meet-the-b...
Once you eliminate the sun you just need to make sure that wind alleys are set up to keep air moving through the city and have regular green spaces with water to help reduce air temperature. This can be done quite sustainably - Las Vegas is actually a great example of (rather) sustainable water use from a city built in the middle of a desert.
- the large amount of bike culture in Minneapolis, people ride all year long (once you're moving you'll stay pretty warm with the right gear) https://gearjunkie.com/biking/minneapolis-bike-capital
- the bike culture in Finland where it's even colder: https://www.theguardian.com/environment/bike-blog/2020/feb/0...
the difference in most of the US that it's not prioritized by local government, bike lanes don't get plowed and fill up with gravel, there's not sufficient bike infrastructure to being with etc
(Yes, it's too hot to enjoy biking during the day. But public transport is great, and has aircon.)