No officer or employee of the department of motor vehicles who has conducted a hearing concerning an owner or operator of a motor vehicle or motorcycle shall be required to appear in any court as a witness in a civil action in which such owner or operator is a party except pursuant to a subpoena signed by a judge of a court of record, or a judge of the court in which the action is pending, issued upon an application to such judge after, at least, one day's notice to the commissioner or a deputy commissioner of motor vehicles.
New York Legal Code