Reduction in Late-Night Violence following the Introduction of National New Zealand Trading Hour Restrictions.

Abstract

This study aimed to assess the early impact of national alcohol trading hour restrictions on nighttime violence in New Zealand. The new national maximum trading hour restrictions prohibited 24-hour trading by reducing hours to between 8 am and 4 am for on-premises and between 7 am and 11 pm for take-away outlets. A telephone survey of alcohol outlets was undertaken to determine actual trading hours before the law change. Interrupted time-series analysis modeled weekly nighttime police calls for service for assault (i.e., between 9 pm and 6 am) and late-night police calls for service for assault (i.e., between 4 am and 6 am) from 2005 to 2015. Daytime police calls for service for assaults were used as the comparison group. Abrupt permanent changes and gradual permanent changes were assessed. The survey found that only 1% of alcohol shops, 9% of supermarkets, and 6% of bars/nightclubs were affected by the hour restrictions because they did not trade as long as their licensed hours permitted in the first place. The time-series analysis found no effect of the national trading hour restrictions on nighttime police calls for service for assaults. However, a significant gradual permanent decrease of 12.4% was found for late-night assaults between 4 am and 6 am (i.e., those likely related to the on-premises hour restriction). This equated to a weekly average decrease of 4.3 police calls for service for assaults between 4 am and 6 am following the law change. The national trading hour restrictions for on-premises and take-away outlets affected only a small proportion of premises, and no change in the overall level of nighttime violence was found following the restrictions. Late-night assaults likely related to on-premises, however, did reduce showing the likely effectiveness of trading hour restrictions even when the impact of the law change on the ground was minimal.