There is an increased risk of death or serious injury for occupants who did not wear a seat belt in a crash (Høye 2016). Recent studies have also identified a number of risk factors associated with vehicle occupants who did not wear a seat belt and were killed, which include: vehicle factors; time of day; age; gender; ethnicity; education; and a history of previous offences (see Figure 4 and Appendix A).

In New Zealand, seat-belt wearing rates are high, yet non-seat belt fatalities accounted for 19- 26% of overall motor vehicle occupant road deaths between 2006 and 2016. Over this period, the proportion has fluctuated but in 2015 and 2016 non-seat belt fatalities accounted for 29- 30% of overall motor vehicle occupant road deaths (CAS query 2017). Note that this is likely to be an under-estimate of the true figures as there are a number of “unknown” cases for seat belt wearing.

The fact that these potentially preventable deaths are not decreasing is an issue worthy of investigation. It is important to better understand the contextual factors associated with crashes where seat belts are not worn, so that more relevant and effective road safety interventions can be designed and implemented.

The aim of this research was to determine profiles for seat belt non-users who were killed in motor vehicle crashes, and to better understand trends in seat belt non-use offences. Related to this aim, the following research questions were examined:

• Over the past 5-10 years, how have the levels of people fatally or seriously injured while not wearing a seat belt changed?

• Are there any obvious patterns to crashes including geographic? Seasonal? Temporal?

• Are there any demographic patterns that can be established including age, gender, or any others that the data can reveal?

• What other factors are commonly associated with crashes where seat belts are not being worn such as speed, alcohol or drugs, distraction, vehicle type, drivers vs passengers?