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
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.