Drivers eligible for individual negligent operator hearings whose records suggested that their inclusion in the program would not constitute an unacceptable traffic risk were randomly assigned to groups receiving the standard hearing and to groups receiving probation-by-mail. Probation was generally for a 1-year period, and drivers were given the option of requesting a hearing rather than participating in the program. Probation-by-mail participants completed a 16-item questionnaire. The subsequent fatal and injury accident rates, convictions, and failure to appear rates of both groups were determined over a 6-month period. These factors were also determined for the 3 years previous to the driver's entry into the program. Probation-by-mail drivers had a higher rate of convictions and failures to appear. There were no differences in the groups' subsequent accident rates or in the number of fatal or injurious accidents. The probation-by-mail participants felt that they received a clear explanation of their driver status in the program. These drivers indicated that the notice which they received caused them concern and that they viewed the option to select a hearing or probation-by-mail favorably. Those drivers screened out of the program because they were considered high risks did not have subsequent accident or conviction rates different from the low-risk drivers who received hearings as part of the program. The effect of probation-by-mail on the subsequent accident rates of high risk drivers was not investigated. Copies of forms and the probation-by-mail questionnaire are included in appendices. (NTIS abstract modified)