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They absolutely are. Even if they don't prevent all collisions, they turn T-bones into glancing hits and so save a lot of lives. The worst roundabout beats the

by lmm 2y ago

They absolutely are. Even if they don't prevent all collisions, they turn T-bones into glancing hits and so save a lot of lives. The worst roundabout beats the best 4-way stop any day of the week. Sometimes there really are easy answers.

WillPostForFood 2y ago
No easy answers, no solutions only trade-offs. Perhaps better for safety, but they makes crossing as a pedestrian longer and harder. And while intersections designed for roundabouts can be pretty smooth, retrofitting undersized roundabouts into intersections designed a 4-way makes for ugly and difficult to navigate messes. I like them, but it is a mistake to blindly install them anywhere possible.
- ndsipa_pomu 2y ago
  What's wrong with mini-roundabouts? We've got lots of them here in the UK, mainly in residential areas and I don't see the issue with replacing a 4-way stop intersection (U.S. style) with a mini-roundabout. All that's needed is to remove the STOP signs and splash a bit of white paint onto the road to mark the mini-roundabout. Optionally, build up the mini-roundabout to make it harder to drive over.
- rjmunro 2y ago
  In most of the world, unless the intersection has pedestrian features (like traffic lights with green men or islands with pedestrian waiting areas), it's better to cross the road away from the intersections. Then you only have 2 directions of traffic to worry about. AFAICT, in the US, crossing away from the intersections is illegal in many cases. When Cycling and approaching a roundabout move to the middle of the lane and follow the same routes as a car. Yes you slow the cars a bit but they are supposed to be going slowly anyway. If you don't want to do that, you can get off your bike and cross as a pedestrian would.
bnralt 2y ago
> The worst roundabout beats the best 4-way stop any day of the week. Sometimes there really are easy answers. Maybe you haven't seen the worst ones, then. For instance, one by my house had traffic lines which gave people the wrong impression about the right of way within the roundabout, leading to every vehicle treating driving like that. I actually drove like that as well for a long time - when you're spending every day driving the exact same way that the hundreds of other cars surrounding you are driving, and the lines on the road suggest that it's correct way to drive, it's easy to mistakenly think this is what you're supposed to be doing. Then it hit me one day - this isn't how right of way works in a roundabout at all. I talked to others in the area, who were surprised when I brought it up. That's what the lines implied, that's what everyone _did_, but that's not how it was supposed to be used. Everyone was driving through this incorrectly. And it was a major roundabout, that had some of the heaviest traffic in the city. Maybe it didn't matter because everyone was driving incorrectly, which worked most (but not all) of the time? But when it wouldn't, the accident would be a T-bone, so we can't say that roundabouts eliminate those. Years later someone in the city seemed to realize it, and changed the design of the roundabout. It's better now, but there are still a few areas they overlooked that have the potential to cause accidents.
- Aeolun 2y ago
  Just because you drove wrong does not make the roundabout bad. That would require you to compare accident numbers from before and after. I’m fairly certain the stats lean in favor of even terribly designed roundabouts.
  - bnralt 2y ago
    > Just because you drove wrong does not make the roundabout bad. You seem to have misread my post. Everyone drove wrong. I seemed to be the only one to notice it, and started avoiding that roundabout, because driving with the correct right of way rules during busy times would lead you to t-boning another car. Other people I talked to said "no, that's just how you're supposed to drive on that roundabout" (it wasn't, and the signage was eventually updated many years later). If _everyone_ is driving through it incorrectly doesn't make it a bad roundabout, than I suppose no roundabout can be bad. If it's always the fault of the drivers and never the design, you can't really say 4 way stops are any worse in this regard either.
ensignavenger 2y ago
In some cases, I see roundabouts used in places a stoplight would be much better. It isn't roundabouts vs 4-way stops, its roundabouts vs a whole bunch of other options.
davidgay 2y ago
You can actually screw them up: by our house (in California) they replaced a 4-way stop with a roundabout with no signaling on 2 of the ways, and a stop on the other 2. An absolute disaster, as the 2 ways without the stop assumed they had the right of way over people already in the roundabout. After the neighbourhood complained, it's now a roundabout with 4 stops (not ideal, but not dangerous either).
- Aeolun 2y ago
  What should I imagine when you say roundabout with 4 stops? Isn’t that just an intersection that looks like a roundabout without functioning like one (entirely negating the point)?
  - lozenge 2y ago
    I guess drivers just don't realise they need to slow down or give way to anybody unless there's a stop sign, traffic light or they're turning into a different road.
    - esskay 2y ago
      Surely drivers know what Yield means though right? I guess the US might need yield signs at a roundabout given not all drivers will get the basics of how they work. There should never be a stop sign on a roundabout, the whole point is you're supposed to be able to keep going without stopping at all if theres nobody coming round it.
- talideon 2y ago
  The right solution would've been to remove all the stops. They defeat almost the whole purpose of the roundabout.
  - Ekaros 2y ago
    I thought the standard for roundabouts is yield sings on all entrances. Not stops, just simple yields...
shiroiushi 2y ago
>Even if they don't prevent all collisions, they turn T-bones into glancing hits No, they don't, at least not in America. When you let American traffic engineers design a roundabout, you get this: https://www.google.com/maps/@38.8643875,-77.2755474,583m/ https://www.google.com/maps/@38.8643875,-77.2755474,583m/
- lozenge 2y ago
  That's... Not a roundabout. It would be funny if it weren't so scary.
- esskay 2y ago
  Nobody in their right mind would ever class that as a roundabout. You dont stick a high speed road directly through a roundabout. An actual roundabout DOES solve the tbone issue.
- offices 2y ago
  This reminds me of this oddity in Nottingham: https://osm.org/go/eu8S4TeKc?way=50459468 https://osm.org/go/eu8S4TeKc?way=50459468 (right-hand drive)
- ndsipa_pomu 2y ago
  That looks like a Hamburger Junction (or roundabout interchange https://www.roads.org.uk/interchanges/roundabout-interchange https://www.roads.org.uk/interchanges/roundabout-interchange). I think they're a bad design as they encourage drivers to go fast with the sweeping corners etc. Ideally, a roundabout should be designed to slow traffic joining it to reduce collisions and their severity. Trying to keep vehicles moving quickly at junctions is just asking for trouble.
- USiBqidmOOkAqRb 2y ago
  It's disheartening to see that much parking place around that spot.
- ColinWright 2y ago
  As others have said ... that's not a roundabout. Here's one of my favourite hybrid "roundabout" junctions: https://www.openstreetmap.org/search?query=Boughton%20Heath%20Junction#map=19/53.187559/-2.854042 https://www.openstreetmap.org/search?query=Boughton%20Heath%...
cameronh90 2y ago
Roundabouts not good for pedestrians and cyclists. In London we’ve been replacing roundabouts with other types of junction to improve pedestrian and cyclist safety. We don’t have four way stops though so instead it’ll be min/maj junction or traffic lights.
- robjwells 2y ago
  This is only true of typical UK-style roundabouts which are designed for motor vehicle throughput. It’s extremely common in the Netherlands to replace crossroads and T-junctions with roundabouts to improve safety, but Dutch urban roundabouts are designed with safety as the main priority. This is achieved through single lanes, sharp entries, limiting forward visibility, and pedestrian and cyclist priority (via what are effective zebras). For more information see eg: https://bicycledutch.wordpress.com/2015/10/13/explaining-the-dutch-roundabout-abroad/ https://bicycledutch.wordpress.com/2015/10/13/explaining-the... (Edit: fixed wrong link)
  - cameronh90 2y ago
    We should absolutely be deploying these where we can, but they do take up a lot of space relative to their traffic throughput, and are only really suitable for a fairly narrow range of traffic volumes. NL seems to quite commonly have this kind of physically large but medium traffic suburban junction, but outside of Milton Keynes and the outskirts of some towns that got heavily developed in the 60s, it's hard to see many places where we could just drop it in.
    - tinodb 2y ago
      I don’t think they do! > That the Dutch roundabout, including the cycle tracks all around it, can be built in almost the same space of a traditional junction is the reason why so many are being converted. From: https://bicycledutch.wordpress.com/2014/02/23/junction-design-in-the-netherlands/ https://bicycledutch.wordpress.com/2014/02/23/junction-desig...

by lmm 2y ago

WillPostForFood 2y ago

No easy answers, no solutions only trade-offs. Perhaps better for safety, but they makes crossing as a pedestrian longer and harder. And while intersections designed for roundabouts can be pretty smooth, retrofitting undersized roundabouts into intersections designed a 4-way makes for ugly and difficult to navigate messes. I like them, but it is a mistake to blindly install them anywhere possible.

ndsipa_pomu 2y ago
What's wrong with mini-roundabouts? We've got lots of them here in the UK, mainly in residential areas and I don't see the issue with replacing a 4-way stop intersection (U.S. style) with a mini-roundabout. All that's needed is to remove the STOP signs and splash a bit of white paint onto the road to mark the mini-roundabout. Optionally, build up the mini-roundabout to make it harder to drive over.
rjmunro 2y ago
In most of the world, unless the intersection has pedestrian features (like traffic lights with green men or islands with pedestrian waiting areas), it's better to cross the road away from the intersections. Then you only have 2 directions of traffic to worry about. AFAICT, in the US, crossing away from the intersections is illegal in many cases. When Cycling and approaching a roundabout move to the middle of the lane and follow the same routes as a car. Yes you slow the cars a bit but they are supposed to be going slowly anyway. If you don't want to do that, you can get off your bike and cross as a pedestrian would.

bnralt 2y ago

> The worst roundabout beats the best 4-way stop any day of the week. Sometimes there really are easy answers. Maybe you haven't seen the worst ones, then. For instance, one by my house had traffic lines which gave people the wrong impression about the right of way within the roundabout, leading to every vehicle treating driving like that. I actually drove like that as well for a long time - when you're spending every day driving the exact same way that the hundreds of other cars surrounding you are driving, and the lines on the road suggest that it's correct way to drive, it's easy to mistakenly think this is what you're supposed to be doing. Then it hit me one day - this isn't how right of way works in a roundabout at all. I talked to others in the area, who were surprised when I brought it up. That's what the lines implied, that's what everyone _did_, but that's not how it was supposed to be used. Everyone was driving through this incorrectly. And it was a major roundabout, that had some of the heaviest traffic in the city. Maybe it didn't matter because everyone was driving incorrectly, which worked most (but not all) of the time? But when it wouldn't, the accident would be a T-bone, so we can't say that roundabouts eliminate those. Years later someone in the city seemed to realize it, and changed the design of the roundabout. It's better now, but there are still a few areas they overlooked that have the potential to cause accidents.

Aeolun 2y ago
Just because you drove wrong does not make the roundabout bad. That would require you to compare accident numbers from before and after. I’m fairly certain the stats lean in favor of even terribly designed roundabouts.
- bnralt 2y ago
  > Just because you drove wrong does not make the roundabout bad. You seem to have misread my post. Everyone drove wrong. I seemed to be the only one to notice it, and started avoiding that roundabout, because driving with the correct right of way rules during busy times would lead you to t-boning another car. Other people I talked to said "no, that's just how you're supposed to drive on that roundabout" (it wasn't, and the signage was eventually updated many years later). If _everyone_ is driving through it incorrectly doesn't make it a bad roundabout, than I suppose no roundabout can be bad. If it's always the fault of the drivers and never the design, you can't really say 4 way stops are any worse in this regard either.

ensignavenger 2y ago

In some cases, I see roundabouts used in places a stoplight would be much better. It isn't roundabouts vs 4-way stops, its roundabouts vs a whole bunch of other options.

davidgay 2y ago

You can actually screw them up: by our house (in California) they replaced a 4-way stop with a roundabout with no signaling on 2 of the ways, and a stop on the other 2. An absolute disaster, as the 2 ways without the stop assumed they had the right of way over people already in the roundabout. After the neighbourhood complained, it's now a roundabout with 4 stops (not ideal, but not dangerous either).

Aeolun 2y ago
What should I imagine when you say roundabout with 4 stops? Isn’t that just an intersection that looks like a roundabout without functioning like one (entirely negating the point)?
- lozenge 2y ago
  I guess drivers just don't realise they need to slow down or give way to anybody unless there's a stop sign, traffic light or they're turning into a different road.
  - esskay 2y ago
    Surely drivers know what Yield means though right? I guess the US might need yield signs at a roundabout given not all drivers will get the basics of how they work. There should never be a stop sign on a roundabout, the whole point is you're supposed to be able to keep going without stopping at all if theres nobody coming round it.
talideon 2y ago
The right solution would've been to remove all the stops. They defeat almost the whole purpose of the roundabout.
- Ekaros 2y ago
  I thought the standard for roundabouts is yield sings on all entrances. Not stops, just simple yields...

shiroiushi 2y ago

>Even if they don't prevent all collisions, they turn T-bones into glancing hits No, they don't, at least not in America. When you let American traffic engineers design a roundabout, you get this: https://www.google.com/maps/@38.8643875,-77.2755474,583m/ https://www.google.com/maps/@38.8643875,-77.2755474,583m/

lozenge 2y ago
That's... Not a roundabout. It would be funny if it weren't so scary.
esskay 2y ago
Nobody in their right mind would ever class that as a roundabout. You dont stick a high speed road directly through a roundabout. An actual roundabout DOES solve the tbone issue.
offices 2y ago
This reminds me of this oddity in Nottingham: https://osm.org/go/eu8S4TeKc?way=50459468 https://osm.org/go/eu8S4TeKc?way=50459468 (right-hand drive)
ndsipa_pomu 2y ago
That looks like a Hamburger Junction (or roundabout interchange https://www.roads.org.uk/interchanges/roundabout-interchange https://www.roads.org.uk/interchanges/roundabout-interchange). I think they're a bad design as they encourage drivers to go fast with the sweeping corners etc. Ideally, a roundabout should be designed to slow traffic joining it to reduce collisions and their severity. Trying to keep vehicles moving quickly at junctions is just asking for trouble.
USiBqidmOOkAqRb 2y ago
It's disheartening to see that much parking place around that spot.
ColinWright 2y ago
As others have said ... that's not a roundabout. Here's one of my favourite hybrid "roundabout" junctions: https://www.openstreetmap.org/search?query=Boughton%20Heath%20Junction#map=19/53.187559/-2.854042 https://www.openstreetmap.org/search?query=Boughton%20Heath%...

cameronh90 2y ago

Roundabouts not good for pedestrians and cyclists. In London we’ve been replacing roundabouts with other types of junction to improve pedestrian and cyclist safety. We don’t have four way stops though so instead it’ll be min/maj junction or traffic lights.

robjwells 2y ago
This is only true of typical UK-style roundabouts which are designed for motor vehicle throughput. It’s extremely common in the Netherlands to replace crossroads and T-junctions with roundabouts to improve safety, but Dutch urban roundabouts are designed with safety as the main priority. This is achieved through single lanes, sharp entries, limiting forward visibility, and pedestrian and cyclist priority (via what are effective zebras). For more information see eg: https://bicycledutch.wordpress.com/2015/10/13/explaining-the-dutch-roundabout-abroad/ https://bicycledutch.wordpress.com/2015/10/13/explaining-the... (Edit: fixed wrong link)
- cameronh90 2y ago
  We should absolutely be deploying these where we can, but they do take up a lot of space relative to their traffic throughput, and are only really suitable for a fairly narrow range of traffic volumes. NL seems to quite commonly have this kind of physically large but medium traffic suburban junction, but outside of Milton Keynes and the outskirts of some towns that got heavily developed in the 60s, it's hard to see many places where we could just drop it in.
  - tinodb 2y ago
    I don’t think they do! > That the Dutch roundabout, including the cycle tracks all around it, can be built in almost the same space of a traditional junction is the reason why so many are being converted. From: https://bicycledutch.wordpress.com/2014/02/23/junction-design-in-the-netherlands/ https://bicycledutch.wordpress.com/2014/02/23/junction-desig...