When you are passing a vehicle on the left on a two-lane road, with traffic moving in both directions, you must activate the following signals

On two-lane roads, with traffic moving in both directions, you may pass traffic on the left, if the pass can be completed safely without exceeding the speed limit. In preparing to pass, check the road ahead for sufficient distance and the road behind for other traffic that may be preparing to pass you. Activate left-turn signal before passing and right-turn signal after passing, and before returning to the right lane.