Junction boxes (JBs) are used to improve ETA calculations and routing through complicated intersections, and interchanges. Junction boxes are displayed as multiple segments with multiple inputs and outputs. They are basically a hint editors can give the Waze routing services that “although these few segments are cut in a few places, they generally should be treated as a single point which connects traffic from several sources to several destinations”.
Considering a complex intersection as a single point has several beneficial properties:
- Traffic speed data for each path through the junction box can be collected separately.
- Turn restrictions can also be separately controlled for each path through the junction box.
- Turn Instructions can also be separately controlled for each path through the junction box, read more below.
For ETA purposes, the routing server does not consider segments wholly within the junction box, but rather treats the junction box as if all the segments which enter or exit the junction box are connected to at a single junction node.
Junction boxes are considered only by the routing server. Junction boxes have no effect on navigational prompts. Junction boxes have no visibility in the client or on the live map. Junction boxes do not effect the search engine; the origin or destination of route may be contained in a junction box.
A path is a couple defined by (entry point, exit point) of the JB.
The size and complexity of a JB is limited:
- maximum 16 entry/exit points
- maximum size is 1km long and 1km wide
- maximum 16 paths going thru any given node
In BeLux, JB are only manageable by editors of level 4+.
It is possible to configure, for each path, a JBTIO, which becomes the unique instruction for that path.
To configure a JBTIO, simply select the entry point of the JB, and apply a (JB)TIO to the arrow exiting the JB via that path.
JBTIO's disables the default instructions of the arrows along the inside path, and any TIO along the inside path disables the JBTIO's.
Using Far Turns in Lane Guidance of a JB
When applied to a regular segment, Lane Guidance (LG) allows assigning lanes to each turn exiting the segment. When LG is applied to a segment entering a JB, one can also assign lanes depending on the turns exiting the JB. Let us call "immediate turn" a turn exiting the segment, and "far turn" a turn exiting the JB.
For a segment entering a JB, the LG configuration will display two sections:
- The usual "Turns" section, with one row for each immediate turn
- The "Far Turns" section, with one row for each far turn reachable from the segment being configured
Each row allows selecting lanes, setting the image of the arrow, and, for "continue straight", setting the "view and/or hear" options.
For each (immediate) turn in the first section, you must decide if you want to involve the far turns in the selection of lanes, or not. If yes, do not select any lane for that turn in the first section, and, in the second section, select lane(s) for each corresponding far turn. If no, select lane(s) in the first section, and, in the second section, do not select any lane for the corresponding far turn(s).