Turn instructions are set at the location where the turn is made. So turn right on the entrance segment, and left on the intermediate segment. See below for straight ahead instructions.
The instructions are linked to the first junction node of the intersection.
LG can simply be set at intersections that have a Junction Box (JB) over them. This can simply be done by L3 editors, as long as the segments are locked at that level.
At an H intersection, the divided road has no intermediate segment. There, LG can be fully set to the input segment. Depending on the angles, this can also apply to parts of a ⛛ intersection.
Forced straight arrows on the input segment do not work for heuristics.
If there is one lane on the entrance segment for turning left (and possibly straight ahead), the intermediate segment will also only have one lane. This is the only exception to the rule that LG is not set for a single lane, otherwise the heuristic will not work.
