User:Atrophicshiner/sandbox View history

Turn lanes

Firstly, the majority of junctions do not need turn lanes at all. Waze gives advanced warning of upcoming turns, it is up to the user to pick the relevant lane for the approaching turn. Turn lanes are only really needed if they are really long, or the junction is sufficiently complicated to need clearer navigation instructions.

When not to map turn lanes

• When the turn lane is too short (<200ft)
• When the turn lane is not distinct from the main carriageway
• When the turn lane splits at or near the main carriageway stop line.

Turn lane too short

Turn lane not distinct

When turn lane may need mapping

• When the turn lane splits from the main carriageway with a physical barrier separation
• Complex junctions that benefit from additional instructions.

If turn lanes really are of benefit to the driver, then they should be mapped in the following way:

• The turn lane segments should have no name, so that the instructions read out the name of the next street.
• The Road Type should match the type of the roads they lead to (and never ramps). Only the main carriageway stays as the higher Road Type.
• The angle at the beginning of the turn lane should be shallow, so that Waze says Keep Left / Right at that point.
• The end of the turn lane should have a clear turn instruction near to the give-way point, unless the traffic merges onto the new road with right-of-way.