Four were academic buildings on the campus of North Carolina State University and two were office buildings in
downtown Raleigh.
Each building had six to eight floors.
Buildings were chosen partly based on the location of the stairwell relative to a single elevator in the area; the location of stairs had to be conspicuous (usually immediately adjacent to the elevator) in order to minimize the cost of complying to the sign.
In other words, finding and using the stairs was relatively easy
(Wogalter et al, 1989).