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The Beauty of Roundabouts

31 pointsby ngruhnlast Monday at 5:53 AM40 commentsview on HN

Comments

propter_hoctoday at 2:48 AM

My best friend is a highly experienced civil engineer, specialized in designing intersections. His take on roundabouts:

- They are adored by urban planners because they look nice and you can put a statue or fountain in the middle

- They reduce T-bone collisions

However:

- Small fender benders and sideswipes are much more frequent

- They use way more area

- They work where each direction has an approximately equal amount of traffic. However, usually, one direction (north/south, say) has a larger share of the traffic. In those cases, the bulk of traffic all needs to slow down, downshift, turn a bit in one direction and then turn a bit in the other direction for the minority of traffic that's bleeding on or off the main artery. In those cases, a traffic light is better because the timing can be adjusted to the proportion of traffic from each direction (and more flexible since it can be adjusted over time).

- Finally, they're also (mostly) worse for cyclists and pedestrians.

Essentially, they have use cases, especially in small towns, and they're pretty, but they're usually not the right engineering solution.

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rusty_ricktoday at 1:46 AM

This led me down somewhat of a rabbit hole looking at roundabouts, then to the official roundabout page from the Department of Transportation, where I couldn't believe my eyes to see that National Roundabout Week is next week: https://highways.dot.gov/safety/intersection-safety/nrw

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teddyhtoday at 1:22 AM

> Roundabouts come with this otherwise unused patch of land in the middle. Apparently, it has become common practice around the world to put some random art there, or a little green space, or a fountain, or a "welcome to this town" sign.

Or a dog: <https://en.wikipedia.org/w/index.php?title=Roundabout_dog&ol...>

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brudgerslast Monday at 7:06 PM

[edit: for clarity, I am not against roundabouts]

I don't have real expertise in civil engineering

Traffic lights have a smaller physical footprint and require less construction activity.

Traffic lights fit on a cost spectrum from two stop sighs, to four stop signs, to stop signs plus blinking lights, to non-trivial signaling.

First make it work. Then make it good. Then make it fast.

Engineering is not a one size fits all discipline.

[edit: I have a background in urban planning, architecture, and real-estate development]

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herbstlast Monday at 7:35 AM

The city I grew up in had no roundabouts back then. Today it does have some, some were even made and removed again since. People there hate roundabouts.

The city I live nearby now has so many roundabouts that I can drive for over an hour without seeing a traffic light. It always had those, people are used to using them.

Guess what works better and barely has any traffic issues at all.

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Bimostoday at 2:54 AM

I think here in China we are not super fan of roundabouts. But we got a 4-lane roundabout with traffic lights [1] and a roundabout on elevated roads with traffic lights. [2]

[1] https://maps.app.goo.gl/rY6AH8nUEKvRuk1LA

[2] https://maps.app.goo.gl/Wea6Wt5FwHgKmG4C9

grebctoday at 1:39 AM

I like roundabouts over lights at small intersections. I still prefer simple give way/stop that changes the next intersection over roundabouts.

Lights suck unless there’s sufficient traffic.

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YuechenLitoday at 2:52 AM

The key disadvantage of a roundabout is that it takes up more space and is harder to setup than plopping down a couple of stop signs.

They are awesome otherwise, I do like them better for low traffic intersections though because I don't have to stop and think about if the next car is going to yield or not.

erelongtoday at 2:13 AM

I think I prefer maybe the simplicity of 4 way (or even 2 way) stops

There are some funny intersection videos from idk what country that have no stop signs or lights or roundabouts and somehow lots of people still manage to get through them

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somattoday at 3:42 AM

Reminder that technically a 4-way stop is the smallest possible roundabout.

porneltoday at 1:46 AM

This dreaming about roundabouts is as American as the fantasies about using metric one day.

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pocketmantoday at 2:26 AM

Roundabouts are superior to other intersection types in nearly every case. Two lane roundabouts are a notable exception.

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Bimostoday at 2:41 AM

I was hoping that it was "404 not found"

esafaktoday at 2:18 AM

I was in Aruba recently, and I discovered that they had entirely replaced their traffic lights with roundabouts. Easier to maintain and more efficient in the island's low-traffic regime.

leo_ilandstoday at 3:09 AM

[dead]

elisbcetoday at 2:08 AM

It is so funny to read this because in reality, roundabouts are some of the worst traffic congestion makers :)

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