Roundabout Intersections are roundabouts with up to four ways and turn
angles which makes the turns obvious, e.g. as in:
```
*
*
* * * *
*
*
```
but not
```
*
*
* * *
* *
* *
```
For Roundabout Intersections we issue instructions such as
"turn <direction>" instead of "take the <nth> exit".
At the moment we have a limit on the radius for these Roundabout
Intersections of 5 meters. Which fails to classify a wide range of
Roundabout Intersections in the US (with the US-wide streets).
This changeset removes the Roundabout Intersection radius limit:
- if the roundabout is larger than a threshold and is named we classify
it as a rotary
- if the roundabout matches our criteria for Roundabout Intersections
we classify it as a Roundabout Intersection
- else fallback to plain old Roundabout
There is a second issue with determining a roundabout's radius.
But that's for another pull request (tracking in #2716).
References:
- https://github.com/Project-OSRM/osrm-backend/issues/2716
