That's a great question, and one I've actually wondered about myself while walking around the city. Yes, they do exist! You can find urban trash bins with built-in ashtrays on top in many cities worldwide. These are specifically designed to address cigarette litter, which is a major problem for sidewalks and drains.
The design is pretty straightforward: it's a standard public litter bin, but the top has one or more specially designed grooves or cups, often made of metal, where smokers can safely extinguish and dispose of their cigarette butts. The main idea is to provide a convenient and dedicated place for this type of waste, keeping the butts contained and away from the general trash, which can sometimes be a fire hazard.
You'll often spot these combo bins in high-traffic areas like outside office buildings, near public transport stops, in entertainment districts, and outside bars and restaurants—places where people are likely to smoke. They are a key part of many "Keep Our City Clean" campaigns. While not every single trash bin has this feature, their presence is definitely growing as cities look for practical solutions to reduce street litter. So next time you're out, take a closer look at the public bins; you might be surprised how many have this useful add-on right on top.