Above, outside a university building in Amsterdam, note what fits, and what almost fits.

This device appears to be attempting to nudge the undesirable behavior of littering by tossing used cigarette butts on the ground. This simple move lowers the threshold of effort required to seek out a “proper receptacle” into which to discard one’s cigarette, replacing it instead with a “sanctioned” piece of ground on to which to toss them. While apathy, indifference, or poor aim may have prevailed over a few smokers above, it appears as if for the most part this building’s nicotine aficionados are a conscientious bunch.

For each specialized waste receptacle, consider the amount of time needed to invest in discerning where people are generating and discarding that waste (hint: oftentimes where people tend to wait is a good start for cigarettes). For each behavior your city hopes to nudge, the requisite investment of time needed to understand how that behavior unfolds in-context, and what motivates people to behave in that way in that particular place.