Put reflective tape or paint on stairs at less well-lit stations like Navy Yard and Capitol South.
The east end of Navy Yard station has only one escalator and it goes up. So you have to take the stairs done. Due to poor lighting, I have fallen on more than one occasion. The lighting also is poor at Capitol South. I would guess this would also be helpful at some other stations. I don't expect this to be a top idea, but it's a quick win for Metro and does align with the expressed desire for a safety culture, at least on a small scale.