2 ms·

Roundabouts do not need more space. You can draw a circle on the road and have “roundabout rules” without the need for any car to even turn their wheels.

Lvl999Noob 18d ago
Not a civil engineer but as far as I know, the space is part of the point. If you keep the roads straight but just draw a circle in the middle, you don't have a roundabout. It only works properly if the drivers have to curve in and out of it. You could keep the same space I guess by pinching the roads tighter near the entries/exits but I don't think anyone is talking about that.
- scrlk 18d ago
  The UK has mini roundabouts, which are just a painted white circle on the road: https://upload.wikimedia.org/wikipedia/commons/b/b0/Mini-roundabout.jpg https://upload.wikimedia.org/wikipedia/commons/b/b0/Mini-rou... Drivers treat them as a normal roundabout by giving way to traffic on the right.
  - leni536 18d ago
    I contest that drivers always treat it the same. They often go through the circle/cut th corner when there is low traffic, and I know at least one mini roundabout where traffic is way less frequent in one direction and the other direction is treated as the "main road" without slowing down. I mostly like them though.
embedding-shape 18d ago
> You can draw a circle on the road and have “roundabout rules” without the need for any car to even turn their wheels. If it's physically possible to "skip the roundabout", if it's just a drawing rather than hard barriers, people here (Spain) will just skip it straight up, unless there is a ton of traffic. I think lots of these driving rules and infrastructure has to take local culture into account, as it differs from "We follow laws like our collective lives depend on it" to "We see laws more like suggestions" depending on the country.
yxhuvud 18d ago
That approach fall down flat on nontrivial traffic amounts. Also it requires an actual hindrance in the middle to enforce compliance, and then bigger vehicles won't be able to turn left.
paulnpace 18d ago
Drive a school bus through there. Let me know how that goes.
- crote 17d ago
  Perfectly fine, actually. For example, the one at [0] regularly sees bendy buses[1] traverse it without any issues. The trick is that there's an outer ring of asphalt and an inner layer of paving stones: cars the asphalt as it is far more comfortable to drive, but longer vehicles like buses and trucks can let their rear wheels ride over the raised paved area as well. And yes, it works the same when they are completely round instead of oval - this just happened to be the first clear example I came across. [0]: https://www.google.com/maps/@52.0660752,5.1198197,3a,75y,21.09h,71.52t/ https://www.google.com/maps/@52.0660752,5.1198197,3a,75y,21.... [1]: https://busposities.nl/voertuig/cxx_SolarisUrbino18E_9686 https://busposities.nl/voertuig/cxx_SolarisUrbino18E_9686

Lvl999Noob 18d ago

Not a civil engineer but as far as I know, the space is part of the point. If you keep the roads straight but just draw a circle in the middle, you don't have a roundabout. It only works properly if the drivers have to curve in and out of it. You could keep the same space I guess by pinching the roads tighter near the entries/exits but I don't think anyone is talking about that.

scrlk 18d ago
The UK has mini roundabouts, which are just a painted white circle on the road: https://upload.wikimedia.org/wikipedia/commons/b/b0/Mini-roundabout.jpg https://upload.wikimedia.org/wikipedia/commons/b/b0/Mini-rou... Drivers treat them as a normal roundabout by giving way to traffic on the right.
- leni536 18d ago
  I contest that drivers always treat it the same. They often go through the circle/cut th corner when there is low traffic, and I know at least one mini roundabout where traffic is way less frequent in one direction and the other direction is treated as the "main road" without slowing down. I mostly like them though.

embedding-shape 18d ago

> You can draw a circle on the road and have “roundabout rules” without the need for any car to even turn their wheels. If it's physically possible to "skip the roundabout", if it's just a drawing rather than hard barriers, people here (Spain) will just skip it straight up, unless there is a ton of traffic. I think lots of these driving rules and infrastructure has to take local culture into account, as it differs from "We follow laws like our collective lives depend on it" to "We see laws more like suggestions" depending on the country.

yxhuvud 18d ago

That approach fall down flat on nontrivial traffic amounts. Also it requires an actual hindrance in the middle to enforce compliance, and then bigger vehicles won't be able to turn left.

paulnpace 18d ago

Drive a school bus through there. Let me know how that goes.

crote 17d ago
Perfectly fine, actually. For example, the one at [0] regularly sees bendy buses[1] traverse it without any issues. The trick is that there's an outer ring of asphalt and an inner layer of paving stones: cars the asphalt as it is far more comfortable to drive, but longer vehicles like buses and trucks can let their rear wheels ride over the raised paved area as well. And yes, it works the same when they are completely round instead of oval - this just happened to be the first clear example I came across. [0]: https://www.google.com/maps/@52.0660752,5.1198197,3a,75y,21.09h,71.52t/ https://www.google.com/maps/@52.0660752,5.1198197,3a,75y,21.... [1]: https://busposities.nl/voertuig/cxx_SolarisUrbino18E_9686 https://busposities.nl/voertuig/cxx_SolarisUrbino18E_9686