Some optional turns don't make sense

Not sure if this qualifies as a bug, but reporting it here. I've been away for a while, so I apologize if this has already been discussed elsewhere.

It seems like it's possible to allow all optional turns at an intersection on every stage of a light cycle. Meaning, if there's a cycle in which left turns have priority, I can still turn on going straight through the intersection in the opposite direction as an "optional turn." This is a recipe for disaster in reality, but not when dealing with perfectly safe automatons in a simulation. The upshot is that it seems like there's no penalty to turning on all kinds of dangerous, unrealistic "optional turns" and "optional straights." In essence, every intersection becomes a strange version of a stop sign where the traffic signals just indicate who has priority and when pedestrians can walk or not. I've been able to increase throughput at some intersections dramatically by collapsing multiple phases of a light cycle into two or three "superphases" with all optional turns enabled and then adding an all-walk stage at the end. This has no basis in reality, as far as I can tell, but it works in the game.