I’m not sure if I understand what you’re asking, but if I do:
Assume the box is an existing piece of road and you want to make a road going off to ahead and left. If you click the end of the road and move the cursor as on the left, you will end up with a sharp turn at the node and a straight road to the destination. If you move the cursor as on the right (forward until it snaps out and then up and to the left) you will get a curved road:
