I know of some huge intersections where that simply wouldn't work. Even with constantly moving traffic, practically every person going straight-through would need to come to a near stop to assess the other side. People in the oncoming turn lane would see that as an opportunity to turn through and the person going straight would end up having to stop completely...at a green light...with lots of people behind. Then, the stream of turning cars from the oncoming lane would never stop until the light changes or you DRIVE INTO THE INTERSECTION.
Roundabouts are awesome. They solve all of these problems and drastically reduce congestion.
If following the law, no. Left turn yields to straight when there is no arrow; right turn on red also yields to people with a green light. Not saying this is what happens, but it's how it is SUPPOSED to happen. Just like no one obeys the rules at a 4 way stop. And people treat yield signs like stop signs.
I guess what I'm saying is that 80% of all people on the road shouldn't be allowed to fucking drive. If cops would stop being useless lazy fucks and try ticketing for infractions other than speed, people might have better awareness of the rules on the road. But instead they sit on the side of the road doing the lazy thing - waiting for the radar gun to beep at them. (I mean, jesus. I have seen a dump truck carrying gravel, piled up over to the top of the sides of the truck without the load covered drive RIGHT PAST a state patrol car without even a second glance. It is unlawful to drive without a covered load in WA, and it should be REALLY fucking easy to enforce it. I-405 up here in the Seattle area is COVERED in rocks. I just don't drive it anymore, after having to replace my windshield twice in 4 months.)
tl;dr: I fucking hate traffic cops. They're lazy assholes.