Thank you for your question. I look forward to working with you to provide you the information you are seeking for educational purposes only.
Unfortunately, yes, the police do not have to provide an interpreter on every traffic stop, it would take them forever. Signing a ticket is not an admission of guilt, it is merely an acknowledgment you received the ticket, so no interpreter is legally mandated. Since they were not questioning you about anything and merely issuing a citation, the place to dispute a citation is in court
where you ARE ENTITLED TO A QUALIFIED ASL Interpreter. So, on the street, where they were not questioning you and just were issuing a citation, they did not need to take time to wait for an ASL interpreter to issue the citation, but in court, where you can plead not guilty and contest the citation you are entitled to an interpreter.
It is always best to use a local attorney to represent you in a traffic court case, mainly because even if you are guilty they can get you the best deals (prosecutors tend to give the best deals or even dismissals to attorneys that practice frequently in that court and are known to the court). However, if you feel you can do it yourself with an interpreter it is not mandatory for you to have an attorney. If the officer does not show up in court, then you would ask for a dismissal for lack of a complaining witness.