An offense doesn't need to result in imprisonment or custody to be criminal. A citation is an arrest without custody - you are promising to appear at court. This is generally how summary offenses are handled in many states. This includes summary traffic citations. If you look at the rules for judicial proceedings they will fall under the criminal proceedings. They will also show up on your record. That's how my state and neighboring states work.

I guess maybe your state is very different. Which is part of what I was asking about. Any offense, civil or criminal, must be defined in statute or code. So can you point me to that?