That's a really interesting and practical question. From my observation and experience living in a city, the effectiveness of those trash cans with small openings is a bit of a mixed bag. On one hand, the theory is sound. By physically limiting the size of items that can be thrown away, these designs aim to prevent people from disposing of large bags of household garbage, bulky cardboard boxes, or other oversized items in public bins. This is supposed to keep the bins from overflowing instantly, reduce maintenance costs for the city, and encourage people to use proper bulk waste disposal channels. I've definitely seen fewer giant black bags stuffed into street corner cans where these are installed.
However, their effectiveness isn't absolute. A major downside is "sidecar dumping," where people just leave the bulky item on the ground next to or on top of the bin. So, the waste isn't *in* the bin, but it's still littering the public space. The small opening can also discourage proper disposal of regular, smaller trash if the opening is too fussy or the bin is often full. People might just toss their coffee cup on the rim. Furthermore, determined individuals with large waste often just force items into the opening, damaging the bin or creating a mess.
So, are they effective? They are a *deterrent*, not a complete solution. They likely reduce the *volume* of bulk waste entering the bin itself, which helps with operational efficiency. But for truly solving illegal dumping, they need to be part of a broader strategy: clear public communication about bulk waste pickup, convenient alternatives (like drop-off sites), and maybe even enforcement. The small-opening bin is a useful tool in the toolbox, but it can't fix the problem alone.