That's a great question about a piece of city infrastructure we see every day! Standard urban trash cans, the kind you find on sidewalks, in parks, and near commercial buildings, typically come in a few common sizes. The most frequent capacities you'll encounter are 32 gallons, 64 gallons, and 96 gallons.
The 32-gallon can is often used in lower-traffic pedestrian areas or for specialized recycling streams. The 64-gallon model is a very common workhorse for general public use on busy streets. For high-traffic locations like transit hubs or large public events, the larger 96-gallon containers are standard. Some heavy-duty commercial or industrial areas might use even larger wheeled carts, but the 32-96 gallon range covers most public "urban trash can" designs.
The specific size deployed in a location depends on factors like foot traffic, collection frequency, and the type of waste (general trash vs. recycling). So, while there's variation, you can generally expect a standard public trash can to hold between 32 and 96 gallons.