This is an interesting idea. I assume that the 3D zebra crosswalk is intended to integrate the mental effects of a standard crosswalk and a road block on drivers in the sense that if the zebra markings alone aren’t able to convince drivers to slow down for pedestrians, the added illusion that the markings are elevated will be, since now the safety of drivers is directly threatened. Or perhaps I should make a simpler (and less cynical) assumption that the spectacle of the elevated markings is only intended to draw attention to the fact that the area is a crosswalk and one should drive slowly as no driver, even on first encountering them, is expected to believe that the markings are really elevated.
In either case, I’m interested in the actual effect of the illusion on the locals, who will encounter the crosswalk often, perhaps daily. Assuming that it will initially temper driving speeds, will the effect wear off as local drivers are continually exposed? Will the speed at which they approach the 3D crosswalk increase over time and eventually match the speed at which they’d approach a standard one, which presents neither a threat nor a spectacle?