Hanna's primary research interest centres on the determinants of drink and drug driving. With a specific emphasis on gender dynamics, her research examines how gender, as a social construct, modified the relationship between these factors and substance-impaired driving. Employing both qualitative and quantitative methods, Dr Watling's work captures the complexity and content of gendered drink and drug driving, complemented by a focus on documenting the prevalence and impact of risk factors for substance-impaired driving.