Apart from what some commenters already pointed out (about the orientation of the roads there), I'm not sure how it's going in the US, but in Europe, we have a hierarchy, where the sign on a pole takes precedence over the sign painted on the road.
The hierarchy is:
Police officer's hand signs
Traffic lights
Signs on a pole
Signs painted on the road
According to this, you cannot turn left, even though it looks like a left turning lane.
Here in Finland we just wait for snow, then you can't see the painted one.
Which is why it was such a great idea to replace our solid "you can't pass here" lines from their old bright yellow to EU matching white so that that self driving cars understand them correctly. So now during the winter both of us and the machines can't see them equally well.
Lately the trend is for temporary signs to have yellow background instead of white. So if you see road construction you'll see a yellow background sign.