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/dat...

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.

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).

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.

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...

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.

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.

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.

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

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.

https://www.google.com/maps/place/41%C2%B027'58.2%22N+81%C2%...

https://www.google.com/maps/place/Energieweg,+Nijmegen/@51.8...

That said, my recollection is that the default in the UK is that lanes flare out from the center, so that once you get into the lane you don't have to switch to another to exit.

[0] https://www.google.com/maps/place/Energieweg,+Nijmegen/@51.8...

You're not wrong, but roundabouts degraded the busier they get:

> As at other forms of unsignalized intersection, when traffic flows on an approach exceed approximately 85 percent of capacity, delays and queue lengths vary significantly about their mean values (with standard deviations of similar magnitude as the means). For this reason, the analysis procedures in some countries (Australia, Germany, and the United Kingdom), and this guide, recommend that roundabouts be designed to operate at no more than 85 percent of their estimated capacity.

* https://www.fhwa.dot.gov/publications/research/safety/00067/...

1-, 2-, and 3-lane RAs each have different capacities, and it may not be easy to expand one size to the next larger one depending on what else is in the area, so signals can allow for the general architecture of RAs to be extended without major changes besides putting up some poles and wires.

In the UK there are road markings that indicate a similar flow, but this turboroundabout makes it physical.

* Raised curbs force the outside lane to exit.

* After each exit, there are only 2 lanes left.

* After each entry, there are 3 lanes, a new one starts from scratch on the inside.

Although it appears that Dutch traffic design tries to avoid intersections with more than 4 directions. Better merge a couple of them before the intersection.

I grew up by this roundabout; the south exit joins to a village. Note it has 5 exits, and is slightly tweaked: there are two lanes that go off most of the exits, except the village exit has one lane and actually going off is optional. Every major entrance to the roundabout has four lanes so you get in the lane you want for the exit you want. The minor entrances have fewer lanes so you just sort of race into the lane you need.

Oh, and it has traffic lights as well.

I assume that traffic on the loops always has the right of way over traffic trying to enter the loops?

In that case, why can't you keep going around? At the place where the northbound inner loop becomes the southbound outer loop, it crosses the start of the southbound inner loop. The cars coming from the south trying to enter the southbound inner loop have to yield to the cars on the northbound loop, so it should be perfect safe for those cars to turn onto the southbound inner loop.

Note that allowing this maneuver is necessary if you want to allow eastbound or westbound travelers to make U-turns. If it is not allowed, then only northbound or southbound travelers can make a U-turn on this.

I also disagree that it is simple while you're on it although I have to admit that I'm not a very confident driver at the best of times so maybe that's just me.

What makes it confusing is, I think, the overhead signs in the roundabout. It would be easier without them. Because the arrows pointing up also points towards the incorrect exit at the same time due to the round nature of the road :)

In a "traditional" roundabout, all motorists could perform an extra round and thus clear the roundabout fast and easy. This doesn't work that great in these kind of roundabouts, I guess.

[0] https://www.google.com/maps/place/Energieweg,+Nijmegen/@51.8...

[0] https://www.google.com/maps/place/Energieweg,+Nijmegen/@51.8...

Q: Is such a construction grade-separated and/or are the separate flows in controlled by traffic lights? The diagram isn't that clear...

It looks like a roundabout, it feels like a roundabout but the priority rules are reversed so if you treat it like a roundabout it only ends badly..

See also sub-section in the main EN page:

* https://en.wikipedia.org/wiki/Roundabout#Turbo_roundabouts

However, yes, complicated roundabouts that require perfect knowledge of what lane you need in order to take an exit you can't see in advance do suck. If you find yourself installing a roundabout with more than one lane, you probably should be installing a traffic light instead.

Early mergers are the assholes. You're SUPPOSED to merge late. If you see a sign saying "Construction ahead 3 miles, left lane closed" or something, and you immediately start trying to merge, you're the one doing it wrong.

Early merging creates unpredictability in traffic flow. Zipper merges are safer and lead to shorter merge queues. https://en.wikipedia.org/wiki/Merge_(traffic)#Zipper

Starting to go off topic, but I'm starting to feel I'm the only person the never refers to a lane change as a merge when it isn't a part of a lane ending. IMO, a "merge" should only refer to lanes ending. Otherwise, fighting about "late merging" becomes ambiguous.

Folks commenting on this, thanks for the correction but also you should have picked up from the context (of a tornado roundabout) that I was referring to a lane change.