Petitioner’s driving privileges were suspended for 90 days by the Motor Vehicles Division, because he was involved in a traffic accident during a 30-day driving record suspension. On appeal, petitioner contends that the hearings officer erred in finding that petitioner was given notice of the 30-day driving record suspension. We agree and reverse.

Petitioner’s driving privileges were initially suspended for 30 days on June 16, 1985. The basis of the suspension was that he had committed two traffic violations within one year of a Driver Improvement Interview.1 On June 20,1985, he was involved in a traffic accident. Thereafter, he received notice of a 90-day suspension. The basis of the suspension was that the accident occurred while the driving record suspension was in effect.2

At the hearing below, petitioner denied receiving notice of the 30-day driving record suspension. The hearings officer concluded that notice had been sent. In his final order he stated:

“In the present case, Exhibit #5 (the driving record) indicates that notice was mailed to Petitioner regarding the June 16 suspension and that a return receipt was received by the Division. The record indicates that Petitioner’s address on the driving record corresponds to the address indicated on *416earlier exhibits dated in 1984 and to the address reported by Petitioner when he testified.

“[T]he record indicates that ‘someone’ signed a receipt at Petitioner’s address. That receipt is not in the record, but is noted on the driving record and no evidence has been submitted to contest that notation.

“The requirements of service as indicated in ORS 482.570 have been met. Petitioner’s first contention is without merit.”3

The hearings officer’s finding that notice was sent was based on coded entries on petitioner’s computerized driving record. The parties contend that the entries on which the hearings officer apparently relied are “RET 6/12/85 RCPT, RET 6/16/85 RCPT” and “RET 6/18/85 RCPT.” The meaning of those entries is not self-evident. No evidence was introduced to establish their meaning. Neither was notice of their meaning properly taken under ORS 183.450(4), which provides:

“Parties shall be notified at any time during the proceeding but in any event prior to the final decision of material officially noticed and they shall be afforded an opportunity to contest the facts so noticed. Agencies may utilize their experience, technical competence and specialized knowledge in the evaluation of the evidence presented to them.”

On appeal, the state submitted as an “additional authority,” The Guide To Oregon Driving Records (July, 1986), which explains the coded computer entries on the division’s records. We disregard the guide, because it is an improper attempt to supplement the record. It is basic to appellate procedure that our review is limited to the record developed below. See ORS 183.482(7) and ORS 809.360(3). The hearings *417officer’s finding that notice of petitioner’s 30-day suspension was properly given is unsupported by this record.4 See Hardt v. Bd. of Naturopathic Examiners, 44 Or App 679, 683, 606 P2d 1169 (1980).

Reversed.