That's a really interesting and practical question. It's something many cities grapple with. The short answer is yes, strategically reducing the size of openings on public trash cans can be an effective physical deterrent against people dumping large items like household bags, boxes, or even small pieces of furniture.
The logic is straightforward. A standard, large-opening bin essentially invites misuse. By designing an opening that only accommodates typical street litter—like coffee cups, food wrappers, and small bottles—you create a psychological and physical barrier. Someone with a large bag of home trash would find it impossible to dispose of it easily, forcing them to reconsider. This "nudge" is a key concept in urban design, guiding behavior through subtle environmental cues.
However, it's not a perfect, standalone solution. A major potential downside is increased littering around the bin if the can becomes full more quickly with regular small items. Therefore, this approach must be part of a broader strategy. This includes more frequent collection schedules to prevent overflow, clear signage directing residents to proper bulk item disposal sites or scheduled pickups, and robust public education about the costs and problems of illegal dumping.
In practice, many municipalities use a combination of bin designs: smaller openings in high-litter pedestrian zones and larger, specialized bins in designated areas for predictable bulk waste. Ultimately, while smaller openings can discourage opportunistic large-item dumping, they work best when supported by convenient legal alternatives and consistent public messaging. It's a tool, not a magic fix, but a smart one in the toolkit for cleaner cities.