The common characteristics and behaviors of child occupants in motor vehicle travel.

Child occupant behavior and head position when travelling in child restraint systems (CRS) may have an effect on injury risk in the event of a motor vehicle crash. The current study aimed to describe the common characteristics and behaviors of child occupants during everyday, real-world motor vehicle travel in a sample of Australian families to identify potential safety implications of observed behaviors and head position within the CRS. Two instrumented study vehicles were used by 42 families for approximately two weeks. Continuous video and audio data were collected across 1,651 trips (over 600 hours). An online survey provided additional parent, familial and child occupant data. The characteristics and behaviors of 72 child occupants (aged 14 months to 9 years) who travelled in a forward-facing CRS (FFCRS) or a belt-positioning booster seat (BS) were observed and recorded by manual review of a sample of the video/audio recordings. One quarter of all trips ( = 414) was randomly selected for coding/analysis and, within each trip, one child occupant was selected who was travelling in a FFCRS or BS. Child occupant behaviors, head position within the FFCRS or BS, and other relevant information was coded for each trip during nine discrete five second intervals or 'epochs' (5%, 17%, 25%, 30%, 50%, 53%, 75%, 89% and 95% of trip duration). In the majority of epochs (74%), child occupants' heads were observed to be 'optimally' positioned within the FFCRS or BS. For more than half of the epochs, child occupants were observed to be: correctly restrained (58%) and involved in an interaction with another vehicle occupant (59%). Bivariate analyses revealed that children travelling in a FFCRS were significantly more likely to be observed to have optimal head positions than those travelling in a BS (78% vs. 62%), χ (1) = 86.00, < 0.001. Child occupants who were observed to be 'correctly' restrained were significantly more likely to be observed to have optimal head positions than those who were observed to be 'incorrectly' restrained (80% vs. 20%), χ (1) = 10.33, < 0.01. This is the first naturalistic driving study (NDS) to specifically explore the factors associated with child occupants' head position when travelling in a CRS. Findings from the current study can be used to inform the positioning of anthropometric test dummies (ATD) in CRS testing, guide improvements to CRS/vehicle design, and develop targeted educational strategies to improve child occupant safety.