The Irresistible Urge to Build Cities from Scratch • Hacker News Board

Re: The Irresistible Urge to Build Cities from Scratch

#51

Post by stevekemp » Wed, Nov 07, 2018, 5:59 PM UTC

ElBarto wrote: post #37

close04 wrote: post #35

Earlier quoted context omitted.

> All cities started as a blank slate. Not at all, many cities evolved from towns, that evolved from villages, that evolved settlements, etc. That slow organic growth is different from the very accelerated "add one more tile" or "do it in one go" growth. Imagine the difference between having a baby that grows into an adult, and having an adult from the get go.

At one point there was nothing where every single city now stands. Everywhere it started with a blank slate. The difference is the speed of development and, even more importantly, the level of planning. US cities grew quickly and were planned. Some modern cities that grew very quickly recently are nevertheless messy because they grew without any sort of planning. Some cities are quite old but nevertheless follow a gr…

One interesting city to contrast the differences is Edinburgh, Scotland. The city was established by royal charter in the early 12th century, so it has been around a while, and a lot of the older parts are as you'd expect.

The part which we now call "New Town" was built in stages between 1767 and around 1850 and has an explicit "block-based" design.

More details on Wikipedia, as always:

https://en.wikipedia.org/wiki/New_Town,_Edinburgh

Re: The Irresistible Urge to Build Cities from Scratch

#52

Post by jermaustin1 » Wed, Nov 07, 2018, 6:06 PM UTC

RightMillennial wrote: post #43

oblio wrote: post #36

Earlier quoted context omitted.

Why do you hate them?

No one uses turn signals on them, and you never know when, where, or if someone is going to turn. It's haphazard maneuvering. 4-way stops are far more predictable and functional.

Your first comment is accurate, no one uses turn signals in any of the ones I use on a daily basis either, but that doesn't make them inefficient. In fact I think it keeps everyone on the defensive, and makes them pay more attention before entering.

But as I said in an earlier comment, the reason they kind of suck in the US is we don't seem to do them right.

* A very wide circle (350ft/100m minimum) with 3 lanes

* Each entrance and exit has 2 lanes.

* The outside lane of the circle directly connects the outside entrance with the "first" exit.

* The middle lane of the circle and the inside lane of the entrance allows you to exit at ANY of the exits

* The far inside lane of the circle exits nowhere without a lane change, but allows you to bypass an exit that might be backed up due to traffic.

Re: The Irresistible Urge to Build Cities from Scratch

#53

Post by crwalker » Wed, Nov 07, 2018, 6:30 PM UTC

lou1306 wrote: post #12

Since nobody has cited it yet, see Christopher's Alexander "A city is not a tree" [0] for an architect's take on "natural" vs. plannes cities. [0]: http://worrydream.com/refs/Alexander%20-%20A%20City%20Is%20N...

I thought I was going to hate this essay but it was wonderful.

He discusses the graph structure of a city: it should be a semi-lattice and not a tree, and there we agree entirely.

But a city should be a tree in the sense that it's an organic structure that iteratively improves in response to local knowledge, rather than a centrally planned crystal that assumes perfect foreknowledge of needs.

Re: The Irresistible Urge to Build Cities from Scratch

#54

Post by dukoid » Wed, Nov 07, 2018, 6:33 PM UTC

cylinder wrote: post #5

Are there any cities which are a series of concentric urban rings with parkland between them?

London (for instance) has a green belt: https://en.wikipedia.org/wiki/Metropolitan_Green_Belt

Wouldn't parkland arranged in spokes be better -- with bike lanes for commuting to the center?

Re: The Irresistible Urge to Build Cities from Scratch

#55

Post by jdmichal » Wed, Nov 07, 2018, 6:40 PM UTC

jermaustin1 wrote: post #21

JoeAltmaier wrote: post #14

Earlier quoted context omitted.

We don't do them that way. In my area, roundabouts are put in where traffic occasionally bursts from one direction, and where traffic levels are low. Because they quit working once traffic increases, because it can be impossible to get on if there's continuous flow from another direction. Maybe the lights reported are because the roundabout has outlived its usefulness? A stopgap before ripping it out.

I think that the size of the round about matters. The larger it is, the more opportunity a driver has to get to an internal lane and not destroy on-ramping from other directions. Also the timidness of drivers to enter a circle kills the flow and causes a backup that takes time to clear. I hit 4 different traffic circles on my 40 mile trip home, two of them are 1 lane wide and only about 100 feet wide, the other two a…

Then there's roundabouts that look like this:

https://www.google.com/maps/@27.9775503,-82.8273026,101m/dat...

Multiple two-lane entrances. An inner lane that goes all the way around but cannot exit. An outer lane that has a single break between the incoming and outgoing sides of the same road.

Oh, and cherry on the sundae, it's in a tourist-heavy area, so many drivers have little-to-no familiarity with it. People block the outer lane waiting to move inside when the outer lane disappears. And then block the inner lane waiting to go through the outer lane to exit.

Not all of this is on the drivers...

Re: The Irresistible Urge to Build Cities from Scratch

#56

Post by cimmanom » Wed, Nov 07, 2018, 6:57 PM UTC

jacobush wrote: post #18

eesmith wrote: post #10

Earlier quoted context omitted.

I think it's hard to look at a grid system and say that it's optimized for sales. US urban planning in the late 1800s and early 1900s "emphasized a grid plan, partly out of extensive reliance on foot, horse and streetcars for transportation. In such earlier urban development, alleys were included to allow for deliveries of soiled supplies, such as coal, to the rear of houses which are now heated by electricity, piped…

Cul-de-sacs decrease criminality too. If you go down a cul-de-sacs to do recon, you look out of place.

That doesn't compute for me - at least not in an urban environment. You're safest on the street where there are the most people; and criminals aren't going to try to break into a building if there's an audience. High foot traffic leads to safe cities. Cul-de-sacs discourage foot traffic.

Re: The Irresistible Urge to Build Cities from Scratch

#57

Post by ElBarto » Wed, Nov 07, 2018, 6:57 PM UTC

close04 wrote: post #48

ElBarto wrote: post #37

Earlier quoted context omitted.

At one point there was nothing where every single city now stands. Everywhere it started with a blank slate. The difference is the speed of development and, even more importantly, the level of planning. US cities grew quickly and were planned. Some modern cities that grew very quickly recently are nevertheless messy because they grew without any sort of planning. Some cities are quite old but nevertheless follow a gr…

> At one point there was nothing where every single city now stands. Everywhere it started with a blank slate. Before the city there was a town, or a village. It's not blank slate > city, it's blank slate > something > something else > city. There's some evolution in the middle and that makes the difference. One grows organically over time and goes through different stages until it reaches the "city" stage, one is pl…

It starts with a blank slate...

That's arguing on a distraction, though, as the key is planning, not blank slate.

Re: The Irresistible Urge to Build Cities from Scratch

#58

Post by cimmanom » Wed, Nov 07, 2018, 6:59 PM UTC

tralarpa wrote: post #47

barry0079 wrote: post #3

I'm a huge fan of the winding maze like structure of cities built upon the old. It's nice to be able to wander and explore. I suppose blank slate cities (like most in America) are a lot more convenient to navigate though.

> are a lot more convenient to navigate though It sounds indeed convenient for large cities where millions of people travel daily from one end of the city to the other. But does it matter for smaller cities (<200,000)? I have lived my whole life in "non-grid" cities in various countries and I couldn't imagine to live in a city with straight roads. Where is the fun? Finding an alley that you can use as a short cut, wa…

Even if you're not traveling from one end to another. It's great to be able to figure out where you're going without a map. I may never have been to 90th St. and 3rd Ave in Manhattan, but I know exactly where it is and how to get there from anywhere else in the grid.

Re: The Irresistible Urge to Build Cities from Scratch

#59

Post by jermaustin1 » Wed, Nov 07, 2018, 7:09 PM UTC

jdmichal wrote: post #55

jermaustin1 wrote: post #21

Earlier quoted context omitted.

I think that the size of the round about matters. The larger it is, the more opportunity a driver has to get to an internal lane and not destroy on-ramping from other directions. Also the timidness of drivers to enter a circle kills the flow and causes a backup that takes time to clear. I hit 4 different traffic circles on my 40 mile trip home, two of them are 1 lane wide and only about 100 feet wide, the other two a…

Then there's roundabouts that look like this: https://www.google.com/maps/@27.9775503,-82.8273026,101m/dat... Multiple two-lane entrances. An inner lane that goes all the way around but cannot exit. An outer lane that has a single break between the incoming and outgoing sides of the same road. Oh, and cherry on the sundae, it's in a tourist-heavy area, so many drivers have little-to-no familiarity with it. People blo…

I'd actually say that is close to an optimal traffic circle. I'd add an even inner-er-er lane, make the outside lane a mandatory exit. If you enter in the right lane, you exit. The middle lane connects to the left of each entrance, and is able to exit at ANY of the exits, and the most inner-er lane would allow you to potentially bypass a traffic jam at another exit.

Re: The Irresistible Urge to Build Cities from Scratch

#60

Post by kazen44 » Wed, Nov 07, 2018, 7:26 PM UTC

cimmanom wrote: post #58

tralarpa wrote: post #47

Earlier quoted context omitted.

> are a lot more convenient to navigate though It sounds indeed convenient for large cities where millions of people travel daily from one end of the city to the other. But does it matter for smaller cities (<200,000)? I have lived my whole life in "non-grid" cities in various countries and I couldn't imagine to live in a city with straight roads. Where is the fun? Finding an alley that you can use as a short cut, wa…

Even if you're not traveling from one end to another. It's great to be able to figure out where you're going without a map. I may never have been to 90th St. and 3rd Ave in Manhattan, but I know exactly where it is and how to get there from anywhere else in the grid.

as someone who lives on the other end of the continent, this system was utterly confusing to me because streets are very long in US cities.

Like, alright, ending up at 90th street is relatively easy, except that i ended up at the wrong end of this street, and the walk to the correct house is 2 kilometer...