I remember being a kid in the 1960's dog poop, cig butts, pop tops, and broken glass everywhere. Every vacant lot accumulated junk.
More on topic diesel trucks and buses had the tail pipe coming out of the back. I remember carping at my mom for always stopping right behind buses. And she said, oh you're right.
That's very normal in America. But it's also very normal for people to simply ignore this rule, and leave poop all over the sidewalk.
Similarly, many public parks require that dogs be kept on a leash. However, here again dog owners don't think they need to follow rules, and let their dogs run loose. Reminding them of the rule is usually met with hostility, profanity, and physical threats.