Oral evidence shall be taken only on oath or affirmation. Each party shall have the right to call and examine witnesses; to introduce exhibits; to cross-examine opposing witnesses on any matter relevant to the issue; to impeach any witness; and to rebut evidence. The hearing need not be conducted according to technical rules of evidence, and any relevant evidence may be admitted if it is the type of evidence upon which responsible persons are accustomed to rely in the conduct of serious affairs. The hearing officer shall control the manner in which the hearing is conducted, including the order in which evidence is presented, and the admission and exclusion of evidence. Irrelevant and unduly repetitious evidence may be excluded.