: [[Image:Jct_3_45_ex1.png]] [[Image:Jct_3_45.png]]
But there are issues with this method. Depending on the angle, the client may give a "Keep Right" instruction to the driver when a "Turn Right" instruction is more appropriate. If Minor Highways or above are involved, you will actually get an "''Exit'' Right" which can be confusing in many situations. In some cases, no instruction will be given at all. In the worst case, the routing engine may determine that it isn't possible to make a very sharp turn angle and not suggest the turn at all. (In the example image, heading south, then turning left, to head east.) Finally, automatic map errors may appear with turns from one direction as the path of the turing traffic is "too far" away from the actual junction node (in this example, traveling south, then
turing left to head east).
To eliminate ambiguity, we need to map the junction from a logical point of view. Since we want to be given basic "Turn Left" and "Turn Right" instructions, we have to tweak it so it resembles a basic 90 degree intersection. But how do we do that when the roads don't actually diverge at 90 degrees? We add some geometry nodes to make the branch road leave the main road at close to 90 degrees, then we gradually curve the road to match the true departure angle.