You have it exactly backwards. Players 1 and 2 are facing each other. So Player 1's Left lane is Player 2's Right lane. If Player 1 chooses left while Player 2 chooses right, they will end up in the same lane and crash. That is why the problem states "If players follow the same convention" (i.e., both drive on the left, or both drive on the right) "they'll drive safely".