The impact of road safety policies in a deregulated alcohol tax environment in Hong Kong: a 15-year time series analysis

Background and Aims Hong Kong reduced beer and wine tax in 2007, eliminated taxes on beer and wine and strengthened drink-driving legislation in 2008, and increased police traffic enforcement after the 2014 social unrest. This study aimed to measure the effects of implementing road safety policies on road traffic harm in the context of deregulated alcohol control policy in Hong Kong. Design Population-based interrupted time series analysis using seasonal autoregressive integrated moving average (sARIMA) models. Multiple sensitivity analyses were conducted. Setting Hong Kong, China and Singapore from January 2004 to December 2019. Cases A total of 313 728 road traffic injuries in Hong Kong and 163 773 road traffic injuries in Singapore as controls. Measurements Monthly rates of road traffic injuries, non-fatal injuries and serious/fatal injuries from Hong Kong and Singapore Police Force. Findings The elimination of alcohol taxes and the enactment of road safety legislation in 2008 were associated with immediate reductions in total road traffic injuries of 6.71% (95% CI, 1.99%-11.20%), serious/fatal injuries of 13.80% (95% CI, 1.85%-24.30%) and sustained declines in drink-driving and collisions involving drink-driving. The effects of the 2007 tax reduction were inconclusive. Progressively increasing traffic enforcement was associated with continuous reductions in road traffic injuries by 0.21% per month (95% CI, 0.13%-0.30%), and serious/fatal injuries by 1.10% per month (95% CI, 0.85%-1.35%). Effects at the corresponding timepoints in Singapore did not reach statistical significance; the results were inconclusive regarding confounding effects on both regions. Conclusions Despite weakened alcohol control and increased alcohol sales over the same period, road safety policies in Hong Kong are associated with net reductions in road traffic injuries, particularly serious/fatal injuries.