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I don't understand how the turbo roundabout is any different than a typical two-lane roundabout. It looks like a regular two-lane roundabout from that picture i

I don't understand how the turbo roundabout is any different than a typical two-lane roundabout. It looks like a regular two-lane roundabout from that picture in your link.

lightbyte 7y ago
I think it just is a regular two-lane roundabout? We have one of these nearby me in Cleveland, it works pretty well. https://www.google.com/maps/place/41%C2%B027'58.2%22N+81%C2%B041'28.1%22W/@41.466166,-81.6916995,188m/data=!3m2!1e3!4b1!4m6!3m5!1s0x0:0x0!7e2!8m2!3d41.4661648!4d-81.6911509 https://www.google.com/maps/place/41%C2%B027'58.2%22N+81%C2%...
- bkor 7y ago
  The inside lane changes into the outside lane. This is usually done by traffic analysis. Meaning: it doesn't always immediately change the inside lane into the outside one. It works quite well for roundabouts with heavy uneven traffic (close to an Ikea :-P).
- martijn9612 7y ago
  This is a very elaborate version of the turbo roundabout, checking out streetview might help. https://www.google.com/maps/place/Energieweg,+Nijmegen/@51.8529601,5.8358998,124m/data=!3m1!1e3!4m5!3m4!1s0x47c707d72afd87d5:0xb6179e521003096b!8m2!3d51.8432321!4d5.8244417 https://www.google.com/maps/place/Energieweg,+Nijmegen/@51.8...
DanTheManPR 7y ago
I'm not seeing the difference between this and two lane roundabouts. We have a bunch of these in the southern suburbs of Minneapolis/St Paul, and they work well even on roads with moderately high traffic. My only issue with them is that I find them somewhat scary as a pedestrian during winter. The first few times I encountered a two lane roundabout, I had some concerns about whether you had to cut across lanes to exit in some cases (especially when going straight across the roundabout). But after using it a bit, it's clear that it works pretty well, and that it's no worse than a 1 lane roundabout.
- zamadatix 7y ago
  https://www.google.com/maps/@39.9561738,-86.1623079,150a,35y,359.17h/data=!3m1!1e3 https://www.google.com/maps/@39.9561738,-86.1623079,150a,35y... is a "standard" two lane roundabout. Roundabouts like https://www.google.com/maps/place/Minneapolis,+MN/@44.8833864,-93.2865412,111m/data=!3m1!1e3!4m5!3m4!1s0x52b333909377bbbd:0x939fc9842f7aee07!8m2!3d44.977753!4d-93.2650108 https://www.google.com/maps/place/Minneapolis,+MN/@44.883386... are more similar to a turbo roundabout but does not force traffic out after 3 exits or less, the inner lane could be followed indefinitely.
  - mcv 7y ago
    On that second link, I don't see any roundabout at all. It looks like a regular intersection to me.
    - Ajedi32 7y ago
      Maybe the aerial imagery is out of date? It looks like a regular intersection on the satellite view, but Google Maps has it marked as a roundabout.
      - zamadatix 7y ago
        This is interesting, I seem to be getting newer aerial imagery than either of you https://i.imgur.com/tC6fsQm.jpg https://i.imgur.com/tC6fsQm.jpg
        bena 7y ago
        If you switch to globe view, the image changes.
        zamadatix 7y ago
        Yep that's it, globe view has the newer image and legacy mode has the older image.
burntoutfire 7y ago
The difference is that, on a turbo roundabout, when you're on it, you're not allowed to go straight when on the right lane. Right lane is only for exiting the roundabout, while left lane is for either exiting or going forward to the next exit. This contrasts with the regular roundabout, where if you try to exit from the left lane, you are risking collision with someone on the right lane who's not exiting.
- dghughes 7y ago
  > This contrasts with the regular roundabout, where if you try to exit from the left lane, you are risking collision with someone on the right lane who's not exiting. That's how the roundabouts are built where I am from. You can be in either lane and exit from the middle of outer lane. The right lane must exit the inner lane can go around or exit. Although some people in the outer lanes try to turn left and crash into the people in the inner lanes. I get the difference now, that's how they should be here there would be fewer accidents.
zamadatix 7y ago
In a traditional 2 lane roundabout you aren't forced out of the roundabout. An example would be https://www.google.com/maps/@39.9561738,-86.1623079,150a,35y,359.17h/data=!3m1!1e3 https://www.google.com/maps/@39.9561738,-86.1623079,150a,35y...
- peeters 7y ago
  Are you just talking about being able to make a lane change within the roundabout? Because the outer lane cannot take the third exit in your example (at least according to the lane markings), they must exit before then. In Ontario anyway, the general rule for roundabouts is that you aren't allowed to make lane changes, though they still use a dotted line so as to not make you think you're prevented from entering the inner lane. Edit: I see it now. Took me a while to see how the inside lane stops at two spots. Interesting design. It ensures that you're only crossing traffic when entering, not when leaving, at the expense of it being less flexible (note how in two directions the right lane cannot be used to go straight through, so signing clearly in advance is much more important).
  - Scarblac 7y ago
    On these "turbo roundabouts" there are also kerbstones between the lanes, not just lines. You can cross them but it'll be obvious that was not the intended use. I hate driving them. Somehow every one I drive on seems massively overengineered, and could have been done with a completely normal single lane roundabout. But it's usually not rush hour when I drive there.
cblades 7y ago
Follow a lane around and you'll find that the inside lane becomes the outside and the outside lane exits.
systemtest 7y ago
On a regular two-lane roundabout some people don't use the inner lane when they want to go left, as they are afraid of not being able to merge to the outer lane. This design makes it easier to use the inner lane to go left.
seanalltogether 7y ago
We have one of these close to where I live. The idea is that the inside lane automatically becomes the outside lane after half way around, and when you are on the outside lane you are automatically forced to exit soon after.
mcv 7y ago
Isn't a two-lane roundabout one that simply has two lanes going round? The thing about the turbo-roundabout is that there are actually no lanes going round. Each lane just takes you to your exit. There's no option to stay on the roundabout at that point: you're forced off. It's very restrictive in that sense, but that also means that traffic flows smoothly: other drivers also have no option to merge wrong or try anything weird.
- nybble41 7y ago
  > other drivers also have no option to merge wrong or try anything weird If they're following the markings, yes. We have a 1.5-lane roundabout in my area[1] (two lanes on the north side of the circle, one lane on the south side) fed on the southwest by a two-lane road; the right lane is supposed to be a bypass for vehicles turning right, and does not actually enter the roundabout. Some vehicles still make the attempt, ignoring road markings, adjacent vehicles legally entering the roundabout from the left lane, and even the impending concrete barrier. [1] https://www.google.com/maps/@42.0332849,-91.6029348,100m/data=!3m1!1e3 https://www.google.com/maps/@42.0332849,-91.6029348,100m/dat...
  - bobthepanda 7y ago
    In turbo roundabouts, the markings are usually delineated by raised curbs. The one you linked should've physically separated the right turn lane from the rest of the roundabout if that was the intention. You don't need all that much curb to do it.
kitd 7y ago
The lanes spiral outwards as they go round.
andrew-v 7y ago
On a plain 2-lane roundabout when you're driving the outside lane you are not forced to leave it at the 2nd exit. Sometimes there are even no signs/arrows on the road that require you to do it. It is expected of you, but if you happen to be one of the drivers that suddenly change their minds or you don't know how to drive on roundabouts you could continue driving around in the outside lane. So a typical situation which makes roundabouts dangerous is when you're driving in the inside lane and you want to take the second exit (on a 4-exit roundabout that's going straight). If a driver next to you (in the outside lane) carries on driving until the third exit, they'll crash into you. If it happens to you in Poland the situation even more stressful, because according to law, you are (partly) the responsible party, because you were the one who changed lanes! IMHO, that's why turbine roundabouts are a great idea. Too bad that there aren't many of those or they are implemented incorrectly. See [0]. The outside lane ends in only 2 of 4 exits. Is it 50% safer though? [0] https://www.google.com/maps/@52.2547072,20.9822988,188m/data=!3m1!1e3 https://www.google.com/maps/@52.2547072,20.9822988,188m/data...
- scoot 7y ago
  > a typical situation which makes roundabouts dangerous is when you're driving in the inside lane and you want to take the second exit If you want to take the second exit, you should be in the outside lane to start with. In the UK, for a standard two-lane roundabout, unless indicated otherwise by road markings and/or signs the outside lane is for taking the first or second exit, and the inside lane is for taking the third and subsequent exits. You move from inside to outside as you pass the second exit. There are also rules for indicating correctly that help smooth the traffic flow, but unfortunately many drivers seem oblivious to (or just ignore) them. Also, on smaller two-lane roundabouts more than a few drivers will cut across the inside lane (taking the shortest path) with no consideration for vehicles beside them.
  - mcv 7y ago
    In a regular two-lane roundabout, this difference is arbitrary. Your second exit is the third exit for cars entering before you and the first exit for cars entering later. If someone is entering from your exit, you may still be in trouble when you try to move to the outside lane after the second exit. Hence the turbo roundabout.
usrusr 7y ago
It's a two lane roundabout with an integrated instruction manual that makes it much easier to use.
throw0101a 7y ago
> I don't understand how the turbo roundabout is any different than a typical two-lane roundabout. See: > These designs require motorists to choose their direction before entering the roundabout, thereby eliminating many conflicting paths and choices on the roundabout itself ... * https://en.wikipedia.org/wiki/Roundabout#Turbo_roundabouts https://en.wikipedia.org/wiki/Roundabout#Turbo_roundabouts Basically you have to pre-choose your lane before entering as you are not allowed to change lanes once you're inside. With regular RAs you can change lanes if you wish.

I don't understand how the turbo roundabout is any different than a typical two-lane roundabout. It looks like a regular two-lane roundabout from that picture in your link.

lightbyte 7y ago

I think it just is a regular two-lane roundabout? We have one of these nearby me in Cleveland, it works pretty well. https://www.google.com/maps/place/41%C2%B027'58.2%22N+81%C2%B041'28.1%22W/@41.466166,-81.6916995,188m/data=!3m2!1e3!4b1!4m6!3m5!1s0x0:0x0!7e2!8m2!3d41.4661648!4d-81.6911509 https://www.google.com/maps/place/41%C2%B027'58.2%22N+81%C2%...

bkor 7y ago
The inside lane changes into the outside lane. This is usually done by traffic analysis. Meaning: it doesn't always immediately change the inside lane into the outside one. It works quite well for roundabouts with heavy uneven traffic (close to an Ikea :-P).
martijn9612 7y ago
This is a very elaborate version of the turbo roundabout, checking out streetview might help. https://www.google.com/maps/place/Energieweg,+Nijmegen/@51.8529601,5.8358998,124m/data=!3m1!1e3!4m5!3m4!1s0x47c707d72afd87d5:0xb6179e521003096b!8m2!3d51.8432321!4d5.8244417 https://www.google.com/maps/place/Energieweg,+Nijmegen/@51.8...

DanTheManPR 7y ago

I'm not seeing the difference between this and two lane roundabouts. We have a bunch of these in the southern suburbs of Minneapolis/St Paul, and they work well even on roads with moderately high traffic. My only issue with them is that I find them somewhat scary as a pedestrian during winter. The first few times I encountered a two lane roundabout, I had some concerns about whether you had to cut across lanes to exit in some cases (especially when going straight across the roundabout). But after using it a bit, it's clear that it works pretty well, and that it's no worse than a 1 lane roundabout.

zamadatix 7y ago
https://www.google.com/maps/@39.9561738,-86.1623079,150a,35y,359.17h/data=!3m1!1e3 https://www.google.com/maps/@39.9561738,-86.1623079,150a,35y... is a "standard" two lane roundabout. Roundabouts like https://www.google.com/maps/place/Minneapolis,+MN/@44.8833864,-93.2865412,111m/data=!3m1!1e3!4m5!3m4!1s0x52b333909377bbbd:0x939fc9842f7aee07!8m2!3d44.977753!4d-93.2650108 https://www.google.com/maps/place/Minneapolis,+MN/@44.883386... are more similar to a turbo roundabout but does not force traffic out after 3 exits or less, the inner lane could be followed indefinitely.
- mcv 7y ago
  On that second link, I don't see any roundabout at all. It looks like a regular intersection to me.
  - Ajedi32 7y ago
    Maybe the aerial imagery is out of date? It looks like a regular intersection on the satellite view, but Google Maps has it marked as a roundabout.
    - zamadatix 7y ago
      This is interesting, I seem to be getting newer aerial imagery than either of you https://i.imgur.com/tC6fsQm.jpg https://i.imgur.com/tC6fsQm.jpg
      - bena 7y ago
        If you switch to globe view, the image changes.
        zamadatix 7y ago
        Yep that's it, globe view has the newer image and legacy mode has the older image.

burntoutfire 7y ago

The difference is that, on a turbo roundabout, when you're on it, you're not allowed to go straight when on the right lane. Right lane is only for exiting the roundabout, while left lane is for either exiting or going forward to the next exit. This contrasts with the regular roundabout, where if you try to exit from the left lane, you are risking collision with someone on the right lane who's not exiting.

dghughes 7y ago
> This contrasts with the regular roundabout, where if you try to exit from the left lane, you are risking collision with someone on the right lane who's not exiting. That's how the roundabouts are built where I am from. You can be in either lane and exit from the middle of outer lane. The right lane must exit the inner lane can go around or exit. Although some people in the outer lanes try to turn left and crash into the people in the inner lanes. I get the difference now, that's how they should be here there would be fewer accidents.

zamadatix 7y ago

In a traditional 2 lane roundabout you aren't forced out of the roundabout. An example would be https://www.google.com/maps/@39.9561738,-86.1623079,150a,35y,359.17h/data=!3m1!1e3 https://www.google.com/maps/@39.9561738,-86.1623079,150a,35y...

peeters 7y ago
Are you just talking about being able to make a lane change within the roundabout? Because the outer lane cannot take the third exit in your example (at least according to the lane markings), they must exit before then. In Ontario anyway, the general rule for roundabouts is that you aren't allowed to make lane changes, though they still use a dotted line so as to not make you think you're prevented from entering the inner lane. Edit: I see it now. Took me a while to see how the inside lane stops at two spots. Interesting design. It ensures that you're only crossing traffic when entering, not when leaving, at the expense of it being less flexible (note how in two directions the right lane cannot be used to go straight through, so signing clearly in advance is much more important).
- Scarblac 7y ago
  On these "turbo roundabouts" there are also kerbstones between the lanes, not just lines. You can cross them but it'll be obvious that was not the intended use. I hate driving them. Somehow every one I drive on seems massively overengineered, and could have been done with a completely normal single lane roundabout. But it's usually not rush hour when I drive there.

cblades 7y ago

Follow a lane around and you'll find that the inside lane becomes the outside and the outside lane exits.

systemtest 7y ago

On a regular two-lane roundabout some people don't use the inner lane when they want to go left, as they are afraid of not being able to merge to the outer lane. This design makes it easier to use the inner lane to go left.

seanalltogether 7y ago

We have one of these close to where I live. The idea is that the inside lane automatically becomes the outside lane after half way around, and when you are on the outside lane you are automatically forced to exit soon after.

mcv 7y ago

Isn't a two-lane roundabout one that simply has two lanes going round? The thing about the turbo-roundabout is that there are actually no lanes going round. Each lane just takes you to your exit. There's no option to stay on the roundabout at that point: you're forced off. It's very restrictive in that sense, but that also means that traffic flows smoothly: other drivers also have no option to merge wrong or try anything weird.

nybble41 7y ago
> other drivers also have no option to merge wrong or try anything weird If they're following the markings, yes. We have a 1.5-lane roundabout in my area[1] (two lanes on the north side of the circle, one lane on the south side) fed on the southwest by a two-lane road; the right lane is supposed to be a bypass for vehicles turning right, and does not actually enter the roundabout. Some vehicles still make the attempt, ignoring road markings, adjacent vehicles legally entering the roundabout from the left lane, and even the impending concrete barrier. [1] https://www.google.com/maps/@42.0332849,-91.6029348,100m/data=!3m1!1e3 https://www.google.com/maps/@42.0332849,-91.6029348,100m/dat...
- bobthepanda 7y ago
  In turbo roundabouts, the markings are usually delineated by raised curbs. The one you linked should've physically separated the right turn lane from the rest of the roundabout if that was the intention. You don't need all that much curb to do it.

kitd 7y ago

The lanes spiral outwards as they go round.

andrew-v 7y ago

On a plain 2-lane roundabout when you're driving the outside lane you are not forced to leave it at the 2nd exit. Sometimes there are even no signs/arrows on the road that require you to do it. It is expected of you, but if you happen to be one of the drivers that suddenly change their minds or you don't know how to drive on roundabouts you could continue driving around in the outside lane. So a typical situation which makes roundabouts dangerous is when you're driving in the inside lane and you want to take the second exit (on a 4-exit roundabout that's going straight). If a driver next to you (in the outside lane) carries on driving until the third exit, they'll crash into you. If it happens to you in Poland the situation even more stressful, because according to law, you are (partly) the responsible party, because you were the one who changed lanes! IMHO, that's why turbine roundabouts are a great idea. Too bad that there aren't many of those or they are implemented incorrectly. See [0]. The outside lane ends in only 2 of 4 exits. Is it 50% safer though? [0] https://www.google.com/maps/@52.2547072,20.9822988,188m/data=!3m1!1e3 https://www.google.com/maps/@52.2547072,20.9822988,188m/data...

scoot 7y ago
> a typical situation which makes roundabouts dangerous is when you're driving in the inside lane and you want to take the second exit If you want to take the second exit, you should be in the outside lane to start with. In the UK, for a standard two-lane roundabout, unless indicated otherwise by road markings and/or signs the outside lane is for taking the first or second exit, and the inside lane is for taking the third and subsequent exits. You move from inside to outside as you pass the second exit. There are also rules for indicating correctly that help smooth the traffic flow, but unfortunately many drivers seem oblivious to (or just ignore) them. Also, on smaller two-lane roundabouts more than a few drivers will cut across the inside lane (taking the shortest path) with no consideration for vehicles beside them.
- mcv 7y ago
  In a regular two-lane roundabout, this difference is arbitrary. Your second exit is the third exit for cars entering before you and the first exit for cars entering later. If someone is entering from your exit, you may still be in trouble when you try to move to the outside lane after the second exit. Hence the turbo roundabout.

usrusr 7y ago

It's a two lane roundabout with an integrated instruction manual that makes it much easier to use.

throw0101a 7y ago

> I don't understand how the turbo roundabout is any different than a typical two-lane roundabout. See: > These designs require motorists to choose their direction before entering the roundabout, thereby eliminating many conflicting paths and choices on the roundabout itself ... * https://en.wikipedia.org/wiki/Roundabout#Turbo_roundabouts https://en.wikipedia.org/wiki/Roundabout#Turbo_roundabouts Basically you have to pre-choose your lane before entering as you are not allowed to change lanes once you're inside. With regular RAs you can change lanes if you wish.