The present study uses statewide seat belt observation data coupled with mail survey and driver history data from 4505 licensed North Carolina drivers to address whether non-users of seat belts are overrepresented in crashes and violations, and whether these crashes differ from the crashes of belt users. It also reports on a more in-depth telephone survey of 204 drivers to learn about reasons for seat belt use and non-use and to identify programs that might bring about a change in behavior. Results show that non-users have 35% more accidents and 69% more violations than users. Drivers most likely to increase their belt wearing as a result of a law include females, non-whites, and those with fewer prior traffic violations. Further characteristics of seat belt users and non-users are examined and the findings used to identify approaches to increase seat belt use including appropriate target populations, public information and education needs, mechanisms for delivering messages, enforcement needs, etc.