Junction Box over Roundabout
There are three scenarios where it is necessary to apply a Junction Box over a Roundabout (JuBra):
- Exit options (TRs) must be set to red on the roundabout because the roundabout is built in such a way that driving all the way around is not allowed.
- The roundabout must give appropriate instructions (turn right, straight ahead or left over the roundabout) in order to be able to use the directions from the signs at the roundabout.
- For an exit segment, depending on which side you approach the roundabout, you have to work with different direction names.
The Junction Boxes are drawn all over the Roundabout. Any by-pass segments remain outside the Junction Box.
A Junction Box over a Roundabout (JuBra) is used, among other things, to get the instructions left, straight ahead, right and turn around on roundabouts and to enter RS/TI set per approach direction.
Junction boxes can be used to accomplish these goals:
- They can 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.
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.