A person arrested and charged with operating a motor vehicle while under the influence of narcotic drugs or intoxicating liquor, whatever its alcoholic content, shall have the right to be examined at his or her own expense immediately after the person's arrest by a physician selected by the person, and the officer so arresting or so charging the person shall immediately inform the person of this right and afford the person a reasonable opportunity to exercise the right, and at the trial of the person the prosecution must prove that he or she was so informed and was afforded that opportunity.
R.I. Gen. Laws § 31-27-3