In my 40 years I have never seen a double roundabout and I’m glad of that
If someone from the North does a u-turn, they only obstruct the northern roundabout and never go into the southern one. If someone from the south wants to go 2nd exit of the 2nd roundabout, they only use the southern roundabout where they would go all the way around a normal roundabout.
Milton Keynes?
Hemel Hempstead magic roundabout has entered the chat
Swindon too has a magic roundabout
I’m not a road designer but I would guess there are two main scenarios.
1) In the example you’ve put above imagine traffic tends to go North-West and South-East. A double makes more sense as it would separate the majority of traffic and make for better traffic flow.
2) Imagine east and west were far more minor roads than north and south. Using a double would create more gaps for east and west to pull out
Edit: 3) depending on the position of the roads meeting the roundabout a single roundabout might have to be a very strange shape with tight turns which could be difficult for larger vehicles. So a double makes the turns easier
When five won’t fit.
Maybe lots of traffic comes from the top and bottom, both mostly turning right? This would allow them to do that without getting in each others way… All I can think of
Double roundabout is better if you want to kill people cycling
If you want to cause calamity and cackle in the face of doom and despair, it seems like you could well choose to deploy the double roundabout option
When insurance companies sponsor the roads.
There’s one in St Austell and – sheesh – was that interesting as a first encounter.
Road planners, and highway designers trying to earn their wages and not succeeding
Invariably there’s always enough space for a normal roundabout with filter lanes. But instead they use this monstrosity.
8 > 0
Figure of eight doughnuts
Let’s say you’ve only brought the paint stencil for a mini roundabout. You’ve got the cones up, the tea has been drunk and it’s time to crack on. What are you gonna do? Paint two mini roundabout circles and pretend you meant that from the off.
Yes
Never
As someone who recently passed my test and practiced on these, they should be fresh in my mind. All I can say is I don’t like them.
You can turn right without waiting for (or giving way to) traffic from straight ahead.
You’d typically have a double roundabout where there was a stagger of the arms, though not sure what the advantage would be in this case where there is no stagger and a single central. Island could have been provided. Therefore I can only think it’s due to the balance of flows, possibly high right turner’s from north and south. I’ll check with a modelling colleague on Monday and get back if no one answers before. Agreed, terrible for cyclists tho!
This would cause confusion and fear, thus slowing drivers down to a crawl, and hence a lower chance of accidents… Result!
Didn’t think i’d see the double roundabouts in Warmley on reddit tonight
Lol I actually recognise this one, A420 by Warmley, drive through it fairly regularly to get to the M4 from east Bristol!
It’s not as bad as it looks, not actually the busy a road, but mainly seems to be people going east/west or north/south as that other commenter said.
When the end of year budget review is nearing
Maniac
The two body problem
Is this real? Because I can’t. I just can’t.
No, nobody can
It eliminates one entry into the round about north and south, helping with traffic flow, but is more confusing
I’d avoid Swindon if I were you
They aren’t.
It’s really good for confusing Americans.
Sawbridgeworth U.K. has entered the chat (twinned with French town Bry-sur-Marne)
Can somebody explain to me why a US style crossroads (4 way light signal thing) wouldn’t work in this situation?
When you have in peak hours traffic from both sides that goes right on both with double one like this it wont cross paths and can flow
Man, I miss places where people actually know how to operate cars. Here in Canada that traffic system would be a perfect recipe for gridlock, fender benders and middle aged white ladies in Mercedes having panic attacks.
High Wycombe ones are a joy to behold
That’s rookie numbers, have you been to Swindon?
Ugh, us Americans have almost, almost figured out single roundabouts. Now double ones?
A double roundabout is always better than a single one, if your goal is to make people suffer
It’s telling that nobody here knows the answer. I’ve never encountered a double roundabout that wouldn’t function just as well as a single roundabout. They’re generally rare enough to confuse drivers on the rare occasional they encounter them, and are imho dangerous.
**Traffic Flow Management:** In a complex intersection with multiple entry and exit points, a double roundabout can help manage traffic more efficiently by separating the movement into two distinct phases. Each roundabout serves different parts of the traffic flow, preventing congestion in a single, larger roundabout.
**Increased Safety** By having two smaller roundabouts, vehicles generally move at slower speeds, which reduces the risk of accidents. It also simplifies decisions for drivers, as they only have to deal with one stream of traffic at a time, improving visibility and reaction time.
**Better for Complex Intersections:** Double roundabouts work well in intersections where multiple roads intersect at odd angles. They can allow smoother and more intuitive movements for drivers, minimizing confusion.
**Capacity for High Traffic**: Double roundabouts can handle higher traffic volumes without causing gridlock. By splitting traffic into smaller, manageable flows, vehicles can move more steadily compared to a single large roundabout, which might become overwhelmed at peak times.
Transport planner here
I’ve got no idea
just seems like more opportunities for collision
I would fuck this up so bad as an american. Been staring for like 2 minutes and it still doesn’t make sense.
All dependant on the largest traffic flow. Two minis help when both opposites have heavy inputting traffic. For example the west and east roads have the heaviest input so to help the north and south roads it’s good to segregate the east and west to help the traffic flow smoother. However in most occasions having a long single roundabout is more beneficial as more cars are able to be on the roundabout at the same time. Good example is Ipswich Road roundabout in Colchester (which is one roundabout away from a 5 mini magic roundabout). It used to be two minis but was recently changed to a large long single and traffic now flows quicker through it due to the delay between junctions and being able to have a lot more vehicles on the roundabout at the same time.
47 comments
In my 40 years I have never seen a double roundabout and I’m glad of that
If someone from the North does a u-turn, they only obstruct the northern roundabout and never go into the southern one. If someone from the south wants to go 2nd exit of the 2nd roundabout, they only use the southern roundabout where they would go all the way around a normal roundabout.
Milton Keynes?
Hemel Hempstead magic roundabout has entered the chat
Swindon too has a magic roundabout
I’m not a road designer but I would guess there are two main scenarios.
1) In the example you’ve put above imagine traffic tends to go North-West and South-East. A double makes more sense as it would separate the majority of traffic and make for better traffic flow.
2) Imagine east and west were far more minor roads than north and south. Using a double would create more gaps for east and west to pull out
Edit: 3) depending on the position of the roads meeting the roundabout a single roundabout might have to be a very strange shape with tight turns which could be difficult for larger vehicles. So a double makes the turns easier
When five won’t fit.
Maybe lots of traffic comes from the top and bottom, both mostly turning right? This would allow them to do that without getting in each others way… All I can think of
Double roundabout is better if you want to kill people cycling
If you want to cause calamity and cackle in the face of doom and despair, it seems like you could well choose to deploy the double roundabout option
When insurance companies sponsor the roads.
There’s one in St Austell and – sheesh – was that interesting as a first encounter.
Road planners, and highway designers trying to earn their wages and not succeeding
Invariably there’s always enough space for a normal roundabout with filter lanes. But instead they use this monstrosity.
8 > 0
Figure of eight doughnuts
Let’s say you’ve only brought the paint stencil for a mini roundabout. You’ve got the cones up, the tea has been drunk and it’s time to crack on. What are you gonna do? Paint two mini roundabout circles and pretend you meant that from the off.
Yes
Never
As someone who recently passed my test and practiced on these, they should be fresh in my mind. All I can say is I don’t like them.
You can turn right without waiting for (or giving way to) traffic from straight ahead.
You’d typically have a double roundabout where there was a stagger of the arms, though not sure what the advantage would be in this case where there is no stagger and a single central. Island could have been provided. Therefore I can only think it’s due to the balance of flows, possibly high right turner’s from north and south. I’ll check with a modelling colleague on Monday and get back if no one answers before. Agreed, terrible for cyclists tho!
This would cause confusion and fear, thus slowing drivers down to a crawl, and hence a lower chance of accidents… Result!
Didn’t think i’d see the double roundabouts in Warmley on reddit tonight
Lol I actually recognise this one, A420 by Warmley, drive through it fairly regularly to get to the M4 from east Bristol!
It’s not as bad as it looks, not actually the busy a road, but mainly seems to be people going east/west or north/south as that other commenter said.
When the end of year budget review is nearing
Maniac
The two body problem
Is this real? Because I can’t. I just can’t.
No, nobody can
It eliminates one entry into the round about north and south, helping with traffic flow, but is more confusing
I’d avoid Swindon if I were you
They aren’t.
It’s really good for confusing Americans.
Sawbridgeworth U.K. has entered the chat (twinned with French town Bry-sur-Marne)
Can somebody explain to me why a US style crossroads (4 way light signal thing) wouldn’t work in this situation?
When you have in peak hours traffic from both sides that goes right on both with double one like this it wont cross paths and can flow
Man, I miss places where people actually know how to operate cars. Here in Canada that traffic system would be a perfect recipe for gridlock, fender benders and middle aged white ladies in Mercedes having panic attacks.
High Wycombe ones are a joy to behold
That’s rookie numbers, have you been to Swindon?
Ugh, us Americans have almost, almost figured out single roundabouts. Now double ones?
A double roundabout is always better than a single one, if your goal is to make people suffer
It’s telling that nobody here knows the answer. I’ve never encountered a double roundabout that wouldn’t function just as well as a single roundabout. They’re generally rare enough to confuse drivers on the rare occasional they encounter them, and are imho dangerous.
**Traffic Flow Management:** In a complex intersection with multiple entry and exit points, a double roundabout can help manage traffic more efficiently by separating the movement into two distinct phases. Each roundabout serves different parts of the traffic flow, preventing congestion in a single, larger roundabout.
**Increased Safety** By having two smaller roundabouts, vehicles generally move at slower speeds, which reduces the risk of accidents. It also simplifies decisions for drivers, as they only have to deal with one stream of traffic at a time, improving visibility and reaction time.
**Better for Complex Intersections:** Double roundabouts work well in intersections where multiple roads intersect at odd angles. They can allow smoother and more intuitive movements for drivers, minimizing confusion.
**Capacity for High Traffic**: Double roundabouts can handle higher traffic volumes without causing gridlock. By splitting traffic into smaller, manageable flows, vehicles can move more steadily compared to a single large roundabout, which might become overwhelmed at peak times.
Transport planner here
I’ve got no idea
just seems like more opportunities for collision
I would fuck this up so bad as an american. Been staring for like 2 minutes and it still doesn’t make sense.
All dependant on the largest traffic flow. Two minis help when both opposites have heavy inputting traffic. For example the west and east roads have the heaviest input so to help the north and south roads it’s good to segregate the east and west to help the traffic flow smoother. However in most occasions having a long single roundabout is more beneficial as more cars are able to be on the roundabout at the same time. Good example is Ipswich Road roundabout in Colchester (which is one roundabout away from a 5 mini magic roundabout). It used to be two minis but was recently changed to a large long single and traffic now flows quicker through it due to the delay between junctions and being able to have a lot more vehicles on the roundabout at the same time.