That's a great question! It really comes down to the different jobs they need to do. Think of your backyard bin as a personal tool, while an urban trash can is a piece of public infrastructure.
First, durability is a huge factor. A city bin is built to withstand constant, heavy use and often harsh treatment. You'll see them made from heavy-gauge steel, thick plastic, or concrete. They're designed to be vandal-resistant and weatherproof, standing up to everything from rain and snow to attempted graffiti or kicks. Your home bin just doesn't need that level of armor.
Capacity and access are different, too. Public bins are often larger and have wide openings or specific shapes (like for bottles) to make disposal quick and easy for people on the go. They also need to be serviced efficiently by large collection trucks, so they might have standardized shapes or lifting mechanisms.
Safety and hygiene are critical in public spaces. Many urban cans have features to prevent fires, like enclosed designs or special liners. They also aim to contain odors and discourage pests more effectively than a simple open bin in your yard.
Finally, you're starting to see "smart" city bins with compactors and solar panels. These sensors can alert sanitation crews when they're full, optimizing collection routes. It's all about efficiency and cost-effectiveness on a massive scale, which isn't a concern for a single household.
So, in short, an urban trash can is a heavy-duty, high-capacity, safety-focused workhorse designed for the demanding environment of public life, while your backyard bin is a simpler container for private, controlled use.