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Safety benefits of roundabouts

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Re: Safety benefits of roundabouts

#31

Interesting that there are no listed downsides. I saw a more balanced article a while back and recall that it listed cost (especially of the additional real estate, since roundabouts are larger) as being one downside. And in built-up cities, it's basically impossible to convert traditional intersections to roundabouts, because there's simply no room. It is nice to not have to pay for replacement signals, or have to d…

Roundabouts are great (and common where I live), but a downside is they can be difficult for pedestrians to cross. You need crossings that are set back from the exits, but this also makes it a longer path for the pedestrian.

Re: Safety benefits of roundabouts

#32
post #7

I grew up in a town in Australia nicknamed "The City of Roundabouts". Essentially all intersections in the entire town are roundabouts, including two lane ones, etc. It's quite common to drive the entire length of town (~20 blocks) in reasonably heavy traffic without ever stopping. On a good day you do it in 2nd gear, the whole way. At night you can do it in 3rd gear, because it's exceptionally easy to see headlights…

In my two decades of driving I’ve seen one 4-way stop in Australia. The intersection of Dickson Avenue and Clarendon Street, Artarmon NSW.

Haven’t seen one anywhere else.

Re: Safety benefits of roundabouts

#33
post #20

The greatest thing about roundabouts is that they protect against the idiot that goes through an intersection at full speed. He does that either because he is passed out behind the wheel or because he did not notice a stop sign and thought he had the right of way, or maybe because he just does not care. Well with a roundabout if you just go straight ahead you hit the center circle. Good roundabouts always have a slig…

Good roundabouts always have a slight hill and some kind of barrier (a tree or some kind of statue) in the center

Interestingly enough, a new roundabout was installed in my neighborhood. We considered something pretty to look at in the middle, but the city said no way. "Emergency vehicles need to be able to go through the middle at full speed". Meanwhile, busses have zero issues negotiating the circle at normal driving speeds...

Re: Safety benefits of roundabouts

#34

Safety aside, roundabouts lower traffic significantly by never forcing cars to stop. Congestion increases as cars need to stop because of the inevitable latency propagating along the tails, and having more than one traditional intersections along the way can only make things even worse, so any solution to prevent cars from slowing down to a stop would mitigate those effects.

Until you do what Cambridge, MA has done twice near my house: put a traffic light just outside the roundabout, so when the light turns red, traffic inevitably backs up through the roundabout, locking it up entirely. https://www.google.com/maps/@42.3875777,-71.1422076,18z?entr...

They do that in Sweden all the time. I have no idea how a country that has some amazing minds can come up with the worst road infrastructure designs possible. Most of it’s unsafe so they just lower the speed limit.

Re: Safety benefits of roundabouts

#35

Safety aside, roundabouts lower traffic significantly by never forcing cars to stop. Congestion increases as cars need to stop because of the inevitable latency propagating along the tails, and having more than one traditional intersections along the way can only make things even worse, so any solution to prevent cars from slowing down to a stop would mitigate those effects.

Until you do what Cambridge, MA has done twice near my house: put a traffic light just outside the roundabout, so when the light turns red, traffic inevitably backs up through the roundabout, locking it up entirely. https://www.google.com/maps/@42.3875777,-71.1422076,18z?entr...

I used to drive over there quite a bit. Always terrible.

Re: Safety benefits of roundabouts

#36
Here in France they have both types of roundabouts, yield-to-left-on-entry and yield-to-right. They are well signaled, so there is no confusion. The latter type is less common and seems to be mostly in less-busy areas. I'm not sure why they still use them though. Is it because you have better visibility to the right, since you're already in the intersection? It's an interesting design choice.

Re: Safety benefits of roundabouts

#37
post #31

Interesting that there are no listed downsides. I saw a more balanced article a while back and recall that it listed cost (especially of the additional real estate, since roundabouts are larger) as being one downside. And in built-up cities, it's basically impossible to convert traditional intersections to roundabouts, because there's simply no room. It is nice to not have to pay for replacement signals, or have to d…

Roundabouts are great (and common where I live), but a downside is they can be difficult for pedestrians to cross. You need crossings that are set back from the exits, but this also makes it a longer path for the pedestrian.

Tunnels and bridges are used in the UK. And those tunnels are horrible.

Re: Safety benefits of roundabouts

#38

Safety aside, roundabouts lower traffic significantly by never forcing cars to stop. Congestion increases as cars need to stop because of the inevitable latency propagating along the tails, and having more than one traditional intersections along the way can only make things even worse, so any solution to prevent cars from slowing down to a stop would mitigate those effects.

Until you do what Cambridge, MA has done twice near my house: put a traffic light just outside the roundabout, so when the light turns red, traffic inevitably backs up through the roundabout, locking it up entirely. https://www.google.com/maps/@42.3875777,-71.1422076,18z?entr...

I can decisively say anyone advocating for roundabouts has not lived anywhere near Boston.

Re: Safety benefits of roundabouts

#39
post #20

The greatest thing about roundabouts is that they protect against the idiot that goes through an intersection at full speed. He does that either because he is passed out behind the wheel or because he did not notice a stop sign and thought he had the right of way, or maybe because he just does not care. Well with a roundabout if you just go straight ahead you hit the center circle. Good roundabouts always have a slig…

there's a few videos if you look, this one was popular

https://www.youtube.com/watch?v=xTk_kPeA63c

Re: Safety benefits of roundabouts

#40
post #2

Seriously, americans need to learn about these.

As an American, I can assure you that we have loads of these

France has about 30k of them, the UK has about 25k of them and those countries have a fraction of the population of the US.

The us does not have loads of them they are few and far between

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