What you need to understand is that if you are going to contest the citation, neither the clerk nor the judge can grant traffic school until you are convicted after a trial, whether it be a TBD or a court trial. Vehicle Code 41501(a) is very specific regarding this issue stating:
"After a deposit of bail and bail forfeiture, a plea of guilty or no contest, or a conviction, the court may order a continuance of a proceeding against a person, who receives a notice to appear in court for a violation of a statute relating to the safe operation of a vehicle, in consideration for successful completion of a course of instruction at a licensed school for traffic violators…"
California Rules of Court, Rule 4.104(b)(1) gives the clerk the authority to grant traffic school under the provisions of VC 41501(a) stating:
"a court clerk is authorized to grant a request to attend traffic violator school when a defendant with a valid driver's license requests to attend an 8-hour traffic violator school under Vehicle Code sections 41501(a)…"
Neither the Vehicle Code nor the CRC allow either the clerk or the judge (Commissioner) the authority to grant traffic school if you enter a not guilty plea, thus, before a conviction is entered.