Safety belt reminder systems are ubiquitously present in most, if not alI automobiles sold in the United States. Past research has found that the effectiveness of these reminder systems have shown minimal social benefit in the effort to increase safety belt use. The current investigation was conducted to determine if modified reminder systems could improve safety belt use. This research used an electronically equipped research vehicle sponsored by General Motors Corporation. The vehicle's research equipment allowed for the manipulation of different auditory reminder stimuli (i.e., chime, buzzer, and voice), temporal factors (e.g., presentation delays and second reminders) I and the measurement of the driver's safety belt use. Three modifications were explored: the presentation of a Delayed Reminder, Second Reminder, and comparisons of different auditory stimuli. The vehicle also permitted a single subject repeated measure design and methodology that provided process analysis. The results showed that the Delayed Reminder appeared ineffective at increasing belt use, whereas the Second Reminder was found to increase two out of nine subjects' safety belt response rates. The differential effects between the three auditory stimuli (i.e., Chime, Buzzer, & Voice) were inconclusive, though for two subjects the Buzzer and Voice were associated with safety belt increases. / Master of Science