Try to envision this...

There's a weirdly laid out intersection here...coming from one direction, the road is 1-way and the center 2 lanes come to a standard traffic light for straight through traffic.

The left lane makes a gradual curve around and becomes its own lane onto another 1-way street....so if you're turning left you don't have to stop at the light. And the right lane does basically the same thing.

Keep in mind that you are NOT merging into traffic if you turn because as you turn onto the intersecting road, you get your own new lane. There is a GIANT "yield" sign where that right turn is, and about 93% of the time, everybody treats it like a stop sign. They just stop dead in the lane at the turn! Even if the light is green, they do it. I can't tell you how many times I've seen rear-end accidents there when I'm driving by it. What would possess somebody to just STOP there???