Cost savings from a sustained compulsory breath testing and media campaign in New Zealand

This paper evaluates three approaches to compulsory breath testing (CBT) where all drivers stopped are tested: (1) intensive, moderate-profile CBT (plus zero alcohol tolerance for drivers under age 20, which was implemented simultaneously, remains in effect, and unavoidably is commingled with CBT in the effectiveness estimates); (2) CBT plus an enhanced media campaign; and (3) shifting to aggressively visible booze buses, which also streamlined drunk-driver processing, plus enhanced community campaigns against drunk-driving. Approaches 1 and 2 were implemented throughout New Zealand (NZ) in 1993 and 1995. Booze buses and community programs were added for about one-third of the country in late 1996. ARIMA time series models estimated the impact on serious and fatal injury crashes between 10 p.m. and 3 a.m., a proxy for alcohol-related crashes. A benefit-cost analysis assessed return on investment. Cost savings were analyzed from four perspectives: societal, governmental, drunk-drivers', and people other than drunk-drivers (external cost). CBT plus zero tolerance reduced expected night-time crashes by 22.1% and enhanced media by 13.9%. Booze buses yielded a further 27.4% reduction where implemented. The program and associated crash reduction persisted until at least 2001 (the most recent data available). Estimated societal benefit-cost ratios were 14 for CBT, 19 for CBT plus enhanced media, and 26 for the comprehensive package. Government saved more than it spent on the program, especially with booze buses. Aggressive CBT plus zero alcohol tolerance for youth, media blitzes, and booze buses proved dramatically effective. Together, these four interventions halved late night serious and fatal injury crashes. Sustained effort seems to be critical. Better outcomes may be achieved with staged, increasingly visible and inescapable checkpoints than with an "ideal" initial program. It appears CBT is best implemented in conjunction with broader community-centered efforts to reduce drunk-driving.