That's a great question for urban planners and business owners alike! While there's no single universal size, the most commonly specified and popular trash receptacle for dense downtown areas is a 32-gallon (120-liter) to 45-gallon (170-liter) commercial-grade bin.
This size range strikes the perfect balance. It's large enough to handle the high foot traffic and frequent use of a downtown sidewalk without overflowing too quickly. A 32-gallon can might be emptied 2-3 times daily, while a 45-gallon one could potentially last a full business day in a busy spot. Crucially, these bins are still compact enough to not obstruct pedestrian flow on crowded sidewalks.
You'll typically see these as sturdy, rectangular stainless steel or coated metal bins, often with a swinging lid to contain odors and litter. They are part of a coordinated street furniture system. For very high-traffic locations like transit stops or public squares, larger 65-gallon wheeled carts or even solar-powered compactors are becoming more popular. The key is matching the bin's capacity to the specific location's usage patterns and collection frequency to keep the area clean and welcoming.