Outside the elevator one mostly gets these two signs for going up or down.
The idea is if you have to go up, you press the upward pointing arrow. And if you have to go down then you press the downward pointing arrow.
Sorry for explaining the obvious signs but most people do not understand the signs. They end up pressing either different sign from where they want to go (like upward arrow for going down) or both the indicator signs. This leads to confusion and time wastage as people enter the elevator assuming it will go down/up but it is headed for reverse direction.
I just noted on my office elevator that they have added text next to the arrows – “To go up, press this” and “To go down press this”. This is much better and likely to lead people into making the right choice. This is a kind of a nudge with a difference. We usually use images to nudge people as they don’t understand text, here it is the other way round.
Based on this, I would suggest elevator companies to start adopting these arrows instead: