From Wazeopedia


1 byte added, 2 years ago
Elevation of tunnel segments
==Elevation of tunnel segments==
To indicate to the waze servers that a segment is a tunnel in which GPS reception will be absent, tunnel segment segments are marked with an elevation lower than 0. No segments other than tunnels should have an elevation lower than 0.
Roads passing into or out of tunnels should be split into multiple segments at the point where GPS reception is lost or acquired (that is the entrance or exit of the tunnel) such that the segment in the tunnel has a negative elevation and the segments with GPS reception have positive or ground elevation. If a tunnel segment would otherwise end at a junction node within 200 meters of the point where GPS reception is lost the segment need not be split to indicate the entrance or exit precisely.