That's an excellent question that many people responsible for maintaining public spaces eventually ask. The liners for urban trash cans aren't typically standard kitchen trash bags you'd find at any grocery store. Most municipal and commercial trash receptacles require specially sized liners that fit their particular dimensions.
These liners are generally thicker and more durable than residential bags since they need to withstand heavier use and various weather conditions. While you can't purchase them from regular retail stores, they're available through janitorial supply companies, restaurant supply stores, or directly from manufacturers specializing in commercial sanitation products.
Some cities even have specific contracts with suppliers for standardized liners across all public spaces. The key is knowing the exact dimensions of your trash cans and the required thickness (measured in mils) for your specific application. Many suppliers offer customizable options if you need liners for unique or unusually shaped receptacles.
Before making a purchase, check with your local municipal sanitation department or property management company, as they often have preferred vendors or bulk purchasing programs that can save money while ensuring you get the right product for your needs.