Answer: LIT.
A Walkway is a clearly defined path for pedestrians. A staircase can be defined as a flight of stairs.
It is very important for walkways and staircases to be well LIT in order to avoid/prevent any sort of accident or harm whatsoever.
A properly lit staircase will allow an individual see all the flight of stairs and be able to prevent tripping. A properly lit walkway can prevent crime from happening to pedestrians.