You can go green but you must yield to oncoming traffic before turning.
If your driving, stopped at an intersection, and want to go left, can you go on green or do you have to wait for the green arrow?
If there is a green arrow, usually there is a red arrow. If there is no red arrow you must yield till it is safe to turn.
Also
It's a good idea to keep your wheels point straight until you start to make your turn.
That way, if you get hit from behind, you won't be pushed into oncoming traffic.