Most arrows are accompanied by words. When they’re not, the meaning can be open to interpretation. Is this one pointing out water leaks? A schmutzy subway wall?
Arrows on the stairs are optimistic. Stay to the right and you’ll be doing your part to help manage the rushhour crowds. Or just plunge up and down the stairs with everyone else.
Pix and other images 
As one of the teaching profession learned long ago, you must go up the down staircase!