Don't quote me, but i remember being taught that if you arrive roughly at the same time, or within a second or two, the car going straight or right would have the ROW.
However if the car turning left is already stopped and the other car is still moving, the car turning left would have the ROW. Problem is too many people take forever and think the car going straight always has the ROW, I have sat behind people who will let 2-3 people go before they finally take initiative to get moving.
"Speed has never killed anyone, suddenly becoming stationary… That’s what gets you."