Road Elevation
Segments on the map can be set to different elevations and should represent elevation relative to the ground in the real world. By default, the elevation of a segment is set to Ground ("0").
Purpose 
Setting the Road Elevation currently serves two main purposes:
- Preventing automatically generated map problem reports when segments cross without a junction
- Representing bridges in the real world
Effects on display of segments
Road Elevation is displayed differently when viewed in the Waze app, Waze Map Editor (WME), and Live Map:
- The Waze app displays segment elevation according to its road type only.
From top to bottom: Freeways > Major Highways > Minor Highways > Ramps > Primary Streets > Streets
This is the same order seen when setting the road type in the editor. - The WME and Live Map uses the Road Elevation setting to display the relative elevation of the road. It displays the road with the highest "elevation" number on top. Further, the Live Map displays segments with elevations greater than zero in bold, while elevations less than zero appear lighter in color with dashed outlines.
Although the Road Elevation setting does not affect map display in current release versions of the Waze app, it is recommended to set the Road Elevation relative to the physical mapping of the real world. to enable possible future Client application updates to show the same visual representation as the WME.
How to use
When two segments overlap but do not actually connect in the real world, the value of Elevation for each segment must be different.
Elevation -5 is used for non-drivable roads to help ensure that the routing engine does not try to connect or route drivers from roads onto non-roads by mistake. It acts to prevent false system reporting that the roads should be connected.