Junction boxes can be used over roundabouts, covering them either partially or fully. In addition to providing better timing, using a junction box on a roundabout can accomplish these goals:
- As mentioned above, they may be used to correct routing problems.
- They may be used to provide customized turn instructions where signage for a particular exit is different when coming from different entrances.
- They may also be used to override the default navigation instructions.
- For example, divided roads may meet at a small roundabout, where drivers would expect normal instructions based on signs, lane markings and what's common in the region. Rather than using unnatural geometry to force the normal instructions, draw a junction box to encircle the roundabout and set the voice prompt for each path through the roundabout to Turn left, Turn right, U-turn or Continue.
- Conversely, where non-normal instructions are desired that would otherwise be normal, make a junction box voice prompt of Let Waze count the exit number.
- Where small traffic-calming circles have been mapped as roundabouts, a junction box may be used to suppress unnecessary "at the roundabout, continue straight" instructions. Check with local leadership on how to handle traffic-calming circles.
If the junction box completely contains only nodes on the roundabout, its voice prompts will produce the proper roundabout spoken and visual instructions, such as "at the roundabout, turn right" and "at the roundabout, take the fourth exit". Normal and non-normal instructions can be used in the same roundabout. If nodes outside the roundabout are included in the junction box, the navigation instructions will not work as expected, so be sure to only include roundabout segments when using a junction box to control roundabout instructions.
This paragraph was copied from the USA wiki.