Abstract
Results of 1.579 observations of cars entering or exiting campus parking lots showed direct relationships between seat belt wearing and the intrusiveness of the engineering device designed to induce belt usage, and between device instrusiveness and system defeat. F.e.all drivers with working interlocks or unlimited buzzer reminders were wearing a seat belt; but 62% of the systems with interlocks or unlimited buzzers had been defeated, and only 15.9% of the drivers in these cars were wearing a seat belt.