Understanding incorrect seatbelt usage in Queensland, Australia: A multifaceted investigation drawing from deterrence theory and the theory of planned behaviour

Incorrect seatbelt use is a new and emerging safety concern, largely undetected until the recent introduction of seatbelt cameras. While existing literature has predominantly examined seatbelt “non-use”, this self-report survey explored the psychosocial factors underpinning incorrect use (e.g., improper positioning) and perceptions of the effectiveness of deterrence measures such as fines and demerit points. Because few participants reported engaging in incorrect seatbelt use, the study focused on predictors of future intention , a construct known to precede behaviour. Drawing on the Theory of Planned Behaviour (TPB) and Deterrence Theory, the study measured attitudes, subjective norms, perceived behavioural control (PBC), behavioural and normative beliefs, and perceptions of punishment severity, swiftness, and certainty. An online self-report survey assessed intention to wear a seatbelt incorrectly across both driver and passenger contexts. Hierarchical regressions showed that the TPB variables significantly predicted intention. For drivers, subjective norms (positive) and PBC control (negative) emerged as significant predictors, whereas for passengers, attitudes and subjective norms (both positive) predicted intention. Deterrence variables did not explain additional variance over and above the TPB constructs. MANOVAs further revealed that high intenders differed significantly from low intenders, endorsing more favourable behavioural beliefs and stronger normative approval than low intenders. No significant differences emerged in control beliefs. Participants also demonstrated limited awareness of actual penalties, and low perceived certainty of punishment, likely reflecting punishment avoidance. Overall, incorrect seatbelt use remains underreported and under-researched. These findings provide initial insight into its psychosocial drivers and can inform the development of targeted road-safety interventions. • Investigated motivations for incorrect seatbelt use as both a driver and passenger. • Applied TPB and deterrence theory to examine direct and indirect belief influences. • TPB variables predicted intention with differences between drivers and passengers. • Deterrence theory constructs did not explain additional variance in intentions. • Camera-based detection highlights incorrect seatbelt use as an emerging safety issue.