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by martijn9612 2344 days ago
Having lights there defeats a lot of the roundabout. The turboroundabout definitely does not have traffic lights. Look at this[0] implementation, the one you linked qualifies as a "turboplein".

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

2 comments

> Having lights there defeats a lot of the roundabout.

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.

That satellite view describes it perfectly. Especially how it is differentiated from a standard 2 lane roundabout.

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.