Dress Codes on Public Streets

I heard about dress codes for public schools, we just implemented a dress code in Lebanon City Schools in PA. But I had never heard of dress codes for public streets.
According to an article from Wave 3, some lawmakers in Louisiana Georgia and New Jersey think sagging pants should be illegal. Since June, sagging pants have against the law in Delcambre, Louisiana. People, who are found wearing them, face a fine of as much as $500 or up to six months in jail. There are similar laws in other parts of the state.
I completely agree that wearing sagging pants which shows underwear should change. Underwear is to be worn UNDER our clothes. The public doesn't need to know what kind of underwear I'm using. I ask myself "What is going to be next?" "Showing our privates?". I do not agree on the way authorities want to handle this problem by making it illegal.
First of all, authorities (or whoever wants to stop people from wearing inappropriate clothes), should ask themselves "Why do people dress like this?" "Where do they get this from?." There is no question that this style comes from hip-hop culture.
If authorities are making this law because they really desire that people should show self respect by the way dress and not because they just want to punish only hip-hop fans, then authorities need to look for other solutions to the problem such as working hand-in-hand with hip-hop singers and working with parents in general discussing about what message we want to send to young people to help them become good citizens rather than punishing young people who are growing up imitating what they think is "cool."