That's a great question! It really depends on the city and its specific goals, but if I had to name one frontrunner, I'd say various shades of green are arguably the most popular and widespread choice for public trash cans these days.
You'll see green bins everywhere, from parks in Paris to sidewalks in Singapore. The reason is partly psychological and practical. Green is universally associated with nature, cleanliness, and often, recycling (even for general waste, this eco-connotation is beneficial for cities). It's a color that blends reasonably well with urban greenery like trees and grass without completely disappearing. It also doesn't show dirt and minor scuffs as easily as lighter colors.
However, the trend is moving towards functionality and city branding. So you'll also see a lot of:
* Dark Gray/Graphite: Popular for a sleek, modern, and neutral look. It's very business-like and hides stains well.
* Stainless Steel: Common in business districts and upscale areas for a durable, professional, and "clean" aesthetic.
* Color-Coded Systems: Many cities use specific colors to differentiate waste streams. For example, blue for recycling, green for compost, and black or gray for landfill trash. In this system, the "most popular" color might be the one for the most common stream.
* Custom City Colors: Some cities paint bins in their official brand colors or in bright, high-visibility shades like safety yellow or red to ensure they are seen and used.
So, while classic green remains a safe and common bet, the real answer is that cities are increasingly choosing colors based on durability, maintenance, waste sorting programs, and creating a cohesive visual identity for their public spaces. The humble trash can has become part of urban design!