Angela Eichelberger served as the NHTSA Contracting Officer's Technical Representative for the study. The difference in day and night seat belt use among fatally injured passenger vehicle occupants was investigated by personal, environmental, and vehicle characteristics. In each of the 10 years reviewed, seat belt use among fatally injured occupants was lower at night (9 p.m.-3:59 a.m.) than during the day. On average, nighttime use was 18 percentage points lower than daytime belt use. Results indicated that groups with lower seat belt use both day and night were: males; younger occupants; pickup truck occupants; residents of secondary enforcement law States; occupants traveling in rural areas; occupants killed on local roads; occupants killed on weekends; drivers with crashes and violations on their records; drivers likely accountable in the crash; and drivers with high blood alcohol concentrations. Alcohol-impaired drivers comprised more than two-thirds of fatally injured drivers killed at night, and only 26% of these drivers were belted at night. The categories of fatally injured occupants who showed the greatest discrepancy in day and night seat belt use included: occupants 45 and older, those on interstate roads, car occupants, and drivers with clean records.
BACKGROUNDThe disproportionate contribution of nighttime fatalities to the highway death toll has long been recognized. It is becoming increasingly clear that one of the reasons for this situation is that seat belts are less often used during nighttime hours. There are still many gaps in our knowledge about seat belt use at night. The lack of detailed information about nighttime and daytime seat belt use is limiting in two ways: (1) it does not allow identification of specific low-seat-belt-use targets, and (2) it is still unclear why seat belt use is lower at night. A better understanding of night seat belt use compared with daytime use can lead to more focused efforts in targeting relevant populations.
OBJECTIVESCurrently, States only have daytime observational surveys available and do not know the prevailing use rate at night. It is thus of interest to determine the relationship between observed daytime use rates and daytime and nighttime rates of seat belt use in fatally injured occupants. A major part of the study involves investigation of the differential relationship between day and night seat belt use in fatalities by rural/urban location, vehicle types, road type, and occupant age and gender. Also of interest is day and night seat belt use in fatalities by blood alcohol concentration (BAC), driver record, and driver-related factors that indicate the driver was likely accountable for the crash. Differences in day and night use in primary and secondary States were compared, and an analysis was done of States that changed from secondary to primary status in the 1998-2007 period.
METHODSObservational surveys of seat belt use were used to track belt use across years and across States. Data obtained from the Fatality Analysis Reporting System (FARS...
